type BJ-30 main control element

projection mounting

INDIRECT ACTING GENERATOR VOLT­AGE REGULATORS-TYPE OJ-3D provide automatic voltage control of medium

and large size a-c generators such as those in electric utilities and large municipal and industrial generating stations. They are also used with syn­chronous condensers and synchro­nous motors.

The basic equipment consists of a control element mounted on a switch­board panel with necessary control devices, a motor-operated rheostat through which the exciter field cur­

rent is varied, and a contactor panel for either "normal" or "quick"

change in the excitation current.

These regulators provide dependable

ope r a t i o n w i t h m i n i m u m m a in­

tenance, at the same time meeting

the demand for control of quick-re­sponse excitation necessary for im­

proving stability of interconnected

systems under fault conditions and large load changes.

Supersedes DescriptiYe Bulletin 31-270 dated May, 1953 Mailed to: E/259/DB; D64-5A; C/458/DB; C26-5L

flush mounting

WESTINGHOUSE SPECIAL FEATURES

.... HIGH SPEED OPERATION-Regulator operates within three cycles after a volt.

age change. Voltage is settled after a disturbance in minimum time.

.... FIELD FORCING-The regulator has the ability to force the exciter field quickly

to the limit and hold it there indefinitely, if necessary.

.... REGULATOR ElEMENT RESPONSIVE TO AVERAGE THREE-PHASE VOLTAGE, e l i m i ­

nating the danger of false regulator operation upon the occurrence of a n un­

balanced system fault.

.... LOW MAINTENANCE-Since there are no continuously rotating parts and no

moving parts when voltage is normal, wear of moving parts is kept to a minimum

and long life without readjustment or replacement is assured.

.... UNIQUE ANTI-HUNTING ACTION provides for corrective effect proportional to

deviation from normal voltage, yet leaves the light weight moving element

free at all times to respond to voltage changes.

.... INHERENT COMPENSATION FOR TEMPERATURE OF REGULATOR maintains the reg­

ulated voltage within the normal sensitivity band whether the regulator is hot

or cold.

.... SIMPLE ELECTRICAL CIRCUITS make operation easy to understand.

.... VERSATILITY-Regulator can be adjusted readily to match the individual char­

acteristics of various a-c machines, such as slow speed water-wheel driven

a-c generators, high speed turbine driven a-c generators, synchronous motors,

and synchronous condensers. No modification of the standard regulator is

necessary to make such adjustments.

NOVEMBER, 1959 www . El

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Construction

SIal Ion bus

2--------------------------------+-�-------------------------------- 2 3 3

® CD

Current transformer 1,.------1-*--("" "'_.(Required when

Type BJ-30 regulator main control element

® Currenl limiting device_

(When used)

® Cross -currenl compensator (Required when application

involves parallel operation)

1] (---" I

I I I

r----' .-1 l I I L ____ .-J

o Indicating lamps

/Name plate

® Voltage adjusling rheasta t

o E<ciler rheaslal conlrol swilch

Cul out switch

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

I I

3

application involves parallel operation)

L@��Genera,or field

/� ... Moi n exciter

/ Shunl field

Pilol exciter

l-:::�===t Differenlial � field

(When used)

o Motor operated rhe ostat

Pilot e<ciler shunt field

o Contaclor panel

\

�l

, - -- ' , / "\ I \ I \ I I \ I \ I

" " ....... _--/

14 Wires 10 conlactor panel and rheostat assembly

I <> Conduil J L ___ C��u� __ J I � ___ ��- - __ -_-��= ______ .£o�d.!!!t _____________________ J

Layout of a typical type BI-30 regulator installation showing conduit runs and external wiring required to inter_ connect the various units of equipment. Where there are paralleled a-c generators, current transformer connections are also required as shown.

The Type BJ·30 regulator is of the indirect·acting exciter rheo·

static type; that is, it controls the voltage of an a·c machine by

varying the resistance in the field circuit of the exciter that ex·

cites the a-c machine. The exciter should be separately excited

from a pilot exciter or other source. When the a-c voltage is

normal all parts of the regulator are at rest.

For small deviations from normal voltage, the regulator operates

a motor·operated rheostat in the main exciter field circuit to

effect the required change in exciter field current to bring the

a-c voltage back to normal. For large changes from normal

voltage the regulator operates high speed contaclors to insert

or short circuit suitable blocks of resistance in the main exciter

field circuit, to effecl quickly a relatively large change in the

exciter field current, at the same time operating the motor·

operated exciter field rheostat to a corresponding new position.

It is to be particularly noted that the restoration of normal a·c

voltage after a change in load is not determined by the time reo

quired for the rheostat to move from one position to another,

except for voltage changes which are relatively small. For

large changes in voltage, the high speed contaclors cut in or

short out resistance in the main exciter field circuit to obtain

maximum voltage response of the exciter, while the rheostat is turning at maximum speed to its new position. www .

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o MAIN CONTROL ELEMENT

Test term,in'als .. ______________________ ___ Control element main coil _____________ _

Lever arm ________________________ �� Control element core __________________ "" Quick response contacts _____________ """

Normal response contacts _____________ _ Anti-hunt device electromagnets _ __ __ __ _

Dashpots ____________________________ _

The main coil 01 the control element consists of a voltage wind­ing which is energized by a doc voltage, rectified from the three phase a-c source being regulated. A movable iron core is located in the main coil and is supported at its lower end by an aluminum alloy lever arm which carries the normal response and quick response contacts. The pull of the voltage winding on the core is balanced by an adjustable calibrating spring attached to the lever arm. The lever arm is made of aluminum alloy so that relatively little energy to move it through its range of travel is required.

There are two groups of contacts in the main element assembly: the normal response R-L contacts mounted near the right hand end of the lever arm and the quick response AR-AL contacts mounted near the center of the lever arm. The lever arm is so mounted that its movement prcduces a sufficient wiping action of the contacts to insure reliable contact. The contacts are made of a precious metal alloy, designed to stand severe duty and long service with a relatively little maintenance. Tests involving one-half million operations of these contacts have been made and their excellent condition after such tests indicated that several times as many operations could be made without maintenance being required.

ANTI-HUNTING DEVICES-Each group of contact assemblies in· cludes an anti-hunt device. Each anti-hunt device consists of a small electro-magnet, the armature of which is connected by a link to support the stationary parts of one group of contacts. Whenever one of these electro-magnets is energized, the move­ment of its armature causes the gap distance between the upper and lower stationary contact faces to be increased. With this arrangement the anti-hunt devices prevent hunting or over­shooting by means of this contact spreading action, which sep· arates stationary contacts from the moving contacts on the lever

arm without disturbing the position or balance of the lever arm.

Thus, the moving lever arm is free at all times to follow the voltage.

The anti-hunt devices operate with a time delay action which is provided by a dashpot coupled to both the armature of each anti-hunt device and to the main element lever arm. The dash­pot uses a piston having rounded edges which eliminates the problem of alignment. With this design the piston does not

have to be a particularly close fit in the dashpot and wear is minimized, since the liquid used acts as a lubricant. This special liquid is relatively non-evaporating and non-gumming, and reo tains approximately the same viscosity over wide ranges of temperature. Such dashpots need to be inspected only at reg­ular intervals and it is seldom necessary to replace the liquid except after long periods of time. The dashpot's position is fixed by doweling and it can be easily removed and replaced with a screw-driver, without dismantling any other parts.

MOUNTING-The main control element is designed for switch­board panel mounting in either projection or flush mounting case. The control element in projection type case is mounted on a base and protected by a removable glass cover. On the back of the base there is a sub-base which supports the Rectox rectifier and a terminal board. The sub-panel assembly projects to the rear of a switchboard mounting panel and is covered by a protective metal screen. The terminal board and its connecting studs for outgoing leads is exposed at the rear. The front of the flush type case is provided with a removable cover having a glass insert. When the cover is removed, the element may be drawn forward by removing the holding thumb nuts, which per­mits the element to slide out on supporting rods. Suitable stops prevent withdrawing the element entirely away from the case. This construction permits an easy inspection of the element and provides for unhampered maintenance and adjustment when necessary. With the flush type case design the Rectox recti­fier is mounted as a separate unit apart from the regulator on the rear of the switchboard. www .

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o VOLTAGE ADJUSTING RHEOSTAT

The voltage adjusting rheostat provides a means of setting the

regulator to regulate the voltage at the value at which it is to be

maintained. A plate type rheostat of type He or LK design is

normally used, with the rheostat connected in series with the

regulator coil. The standard rheostat is manually operated and

normally mounted on the switchboard panel below the main

control element. The rheostat provides a range of regulated

voltage control of approximately plus or minus 10 per cent from

normal.

The voltage adjusting rheostat can also be supplied with a

motor-operated mechanism, where desired. This makes pos­

sible remote control of this rheostat from a control room, or in

the case of unattended stations remotely controlled by super­

visory control it can be readily operated through the medium

of the supervisory control.

o RHEOSTAT CONTROL SWITCH

The rheostat control switch provides for manual control of the

motor-operated main exciter field rheostat. This switch is of the

type W design and arranged for panel mounting. It has a pistol

grip handle which is normally in the "off" position. The handle

is spring return either from the "lower" or the "raise" position.

o CUTOUT SWITCH

The cutout switch provides for changing from manual to regula­

tor control and vice versa. The Type W switch is designed

for panel mounting and has a round notched handle that stays

in whichever position it is set. The switch has three positions:

"manual," "indicating" and "regulating." In the "manual"

position the regulator is removed from control. In order to

change machine excitation with the cutout switch in this posi­

tion, the rheostat control switch must be turned manually to

either its "lower" or "raise" position. When the cutout switch

is in the "indicating" position only the regulator element is

energized with the motor-operated main exciter field rheostat

still under manual control of the rheostat control switch. In

this position it is possible to balance the control element by means

of the voltage adjusting rheostat, thereby insuring no disturbance

to the system voltage when the cutout switch is turned to the

"regulating" position. With the cutout switch in the "regulat­

ing" position the regulator has complete control of the motor­

operated main exciter field rheostat and its associated field

forcing up and field forcing down contactors.

o INDICATING LAMPS

Two standard, switchboard type indicating lamps enable the

operator to adjust the regulator control element so that the trans­

fer in and out of service may be made only when the excitation

is correct, and not during periods of excitation change. When

the a-c voltage is normal both lights burn brightly. When the

regulator is changing the position of the motor-operated ex­

citer field rheostat, either the raise or lower lamp is short-cir-

cuited, which indicates not only that a change is taking place

but also the direction of the change.

o CONTACTOR PANEL

The contactor panel mounts the contactors that control the op

eration of the motor-operated main exciter field rheostat. This

panel also mounts the high-speed, heavy-duty, field.forcing and

field-reducing contactors which are used to insert and short­

circuit resistance in the exciter field.

Two rheostat motor-control contactors are located on the lower

part of the contactor panel. An adjustable capacity condenser

is connected in parallel with the coil on each of these contactors

and this arrangement causes them to operate as definite time

delay devices. The time setting may be changed to suit the in­

dividual installation by changing the amount of condenser ca­

pacity.

Two high·speed, field forcing contactors are mounted on the

upper part of the contactor panel. One of these contactors is

used to insert resistance in the exciter field circuit and the other

to short circuit resistance. These contactors are designed to be

capable of handling the maximum exciter field current and at

the same time are very high speed in operation. They are de­

signed to stand severe service and silver contacts and effective

blowout coils make them capable of handling high exciter field

currents, such as encountered in applications involving the

slow-speed, water-wheel driven a-c generators. A single-pole,

double-throw knife switch is provided on the contactor panel

for cutting out of service the main contacts of the field forcing

contactors for inspection or maintenance. A small single-pole

knife switch is also provided to render inoperative the contacts

of the high speed "field forcing up" contactor in the exciter

differential field circuit, when such a field circuit is used.

The contactor panel is usually located on the frame of the motor­

operated main exciter field rheostat, since this minimizes the

wiring and decreases the number of conduit runs that would be

required if it were mounted at some other point. If Westing­

house furnishes the exciter rheostat with the regulator the con­

tactor panel is mounted integral with the rheostat assembly and

all interconnecting wiring is installed in the factory.

FIELD FORCING AND FIELD REDUCING RESISTORS-The field forcing

and field reducing resistors, are usually mounted in the motor­

operated exciter field rheostat assembly. This resistor limits the

maximum exciter field current under manual control, and to­

gether with a portion of the main exciter rheostat, provides for

field forcing when it is short circuited by the field forcing con­

tactor under control of the regulator.

The field reducing resistor is provided with slider or taps for

adjustment. By varying the connections, either to different taps,

or by slider adjustment, any required value of resistance may

be secured. This resistor is introduced into the circuit of the

exciter field by the opening of the normally closed field re

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Cuhicle type combination contactor panel and plate ..

type m.otor-operated m.ain exciter field rheostat for

medium. size exciters.

Faceplate type motor�operated main exciter field

rheostat and contactor panel for large size exciters.

o MOTOR-OPERATED MAIN EXCITER FIELD RHEOSTAT

The Type BJ-30 regulator controls the a-c voltage by operating a motor-operated

main exciter field rheosta!. This rheostat must necessarily be 01 special design

for regulator service with its moving parts designed to withstand frequent

operation. The motor mechanism is quiet in operation and has practically no

over-travel after the motor is de-energized. This aids in quickly settling the

voltage, in that the regulator anti-hunt device need not compensate for other

than the electrical inertia 01 the exciter and its a-c machine.

A doc motor 01 the split-field series-wound type is used to operate the rheostat.

This type of motor permits adjustment of speed to meel different operating

conditions and requires minimum control apparatus. Tapped resistors for use

in the motor field circuits are included in the exciter rheostat frame.

The faceplate of the rheostat is usually provided with approximately 200 but­

tons in circular arrangement which connect to the necessary resistance. The

rheostat assembly, in addition to the necessary regulating resistance, also in­

cludes the exciter field permanent resistance, the field forcing and field re­

ducing resistors, and where required the differential field resistance. Pro­

vision is made for those sections 01 resistance which are subject to adjustment

so thai the proper values 01 resistance may be selected with minimum effort

to insure the best performance under any given set of field conditions.

Two general forms of construction are used for the motor-operated exciter

field rheostat:

FOR MEDIUM SIZE EXCITERS a cubicle type assembly is used. The rheostat

resistance is of the plate type with the resistance element completely embedded

in vitreous enamel which provides rigid mechanical support, good heat con­

duction, and complete protection against moisture and corrosion. The rheo­

stat and its motor mechanism are mounted in the lower portion of the cubicle.

The upper portion of the cubicle is used for mounting the contactor panel,

which gives a compact, factory assembled and tested unit.

FOR LARGE SIZE EXCITERS where relatively heavy field current has to be han­

dled, a rheostat having large current capacity is required. A heavy-duly molar

operated faceplate is used and Ihe faceplate buttons or contact segments are

connected on the rear to suitable resistance units. The resistance units are

mounted in a frame on the rear of the faceplate. The rheostat frame is designed

so that the contactor panel may be mounted on the front upper portion.

TYPES OF RESISTANCE-�The connections of the rheostat vary according to the

requirements of the exciter and the a-c machine with which it is used. A

"series" type rheostat is used with an exciter having a standard shunt field

where it is not necessary to reduce the exciter voltage below "residual" volt­

age. A "series" type rheostat is also used with an exciter having shunt field

and differential field where it is necessary to reduce the exciter voltage to zero

or to reverse the field current momentarily. Where Ihe application would

normally require an exciter with a differential field and when the exciter can

not be equipped with such a winding, other types of rheostats, such as the

potentiometer or Wheatstone bridge types are used.

PERMANENT EXCITER FIELD RESISTANCE-For quick-response excitation the ex­

citer field circuit is usually made to have relatively low resistance. For this

reason a block of resistance, called the "permanent" resistance, is sometimes

required lor use in series with the exciter field to limit the current when full

pilot exciter voltage is applied. This resistance is mounted in the assembly

01 the molar-operated excitel' field rheostat, where it is readily accessible.

DIFFERENTIAL FIELD RESISTOR -The differential field resistor, when supplied,

is usually mounted in Ihe assembly of the motor-operated exciler field rheostat. www . El

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Accessories

Cross�current compensator for use with Type BJ .. 30 regulator. (The line drop compensator is 5im�

ilar in appearance.)

Current�Brniting device in projection type caS0

for use with Type BJ-30 regulator. (Flush type

case to :rn.atch main control elernent as shown on

page I is also available.)

� COMPENSATORS

When two or more regulators are operated in parallel, a means must be provided to keep the reactive kva properly proportioned between the paralleled a-c machines controlled by the regula­tors. If suitable reactance for this purpose is not available in the form of an existing tranSlormer bank, it is obtained by providing each regulator with a cross-current compensator operated from a current transformer.

In the case of line drop compensation, line drop compensators energized from current transformers are used, the number re­quired depending on the individual requirements of each partic­ular application. Line drop compensation involves the drop in the line and transformers between the station bus and distrib· uting center. With suitable current transformers and line drop compensators, a voltage component may be introduced into the potential circuits which feed the regulating element to properly compensate for the line drop.

The cross-current and line-drop compensators are of similar con­struction and each is housed in an adequately ventilated case. The amount of compensation may be adjusted by means of the

dial switches, the contacts of which are connected to taps on an auto-current transformer. The movable arm of each dial switch can be solidly fastened to the desired contact point by means of a machine screw. This provides a reliable contact, which is an

important factor in a current transformer circuit. Insulating trans· formers are also mounted in the compensator case and are used to eliminate all electrical connections between the potential and current circuits. With this arrangement the usual grounding of

potential and current transformers may be made in accordance

with standard practice.

Two dial switches are provided on each compensator. One of these switches gives a coarse adjustment and the other a fine ad­justment of the compensation. A total of 24 steps are available on the two switches, which in the case of the standard 12 % com­

pensator gives a V2% change in compensation per step. Each

compensator imposes a burden of 94 volt-amperes at 80% power factor on the current transformer to which it is connected at 4 amperes secondary current, when set at 12 % compensation. The burden is 17 volt-amperes at 80% power factor when set at 5% compensation, which is ample for the usual application.

o CURRENT LIMITING DEVICE

WITH DELAYED ACTION

The current limiting device with delayed action is used with the

Type BJ regulator to limit the load current carried by the a-c ma­

chine by taking control away from the regulator main control

element when the desired load limit is reached. This equipment

is usually used on synchronous-condenser applications.

The current limiting device is essentially a current regulating

element mounted in a suitable case. This device imposes a bur­

den of 60 volt-amperes at 20% power factor on the current trans­

former to which it is connected, at 4 amperes secondary current. In addition, three auxiliary relays are used consisting of a type

SC relay, a type MG relay and a type CV relay. The type SC relay is a current relay which functions to distinguish between a

slowly increasing overload and sudden overload. The type CV relay is a timing relay and controls taking the regulator in and

out of control by means of the type MG auxiliary relay. These

relays function only on sudden overloads and delay cutting out

the regulator for a period that may be adjusted from one to sev·

eral seconds. www . El

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® POTENTIAL TRANSFORMERS

Each regulator requires two potential transformers connected

in open delta to supply energy to the regulator. This provides

a source of energy to operate the regulator control element from

the average three phase voltage of the system and insures a

positive raise impulse with resultant increase in machine ex­

citation on the occurrence of any type of fault.

The volt-ampere burden of the regulator is relatively low, (ap­

proximately 75 volt-amperes at 86.6% power factor on each

potential transformer.) For this reason standard potential trans­

formers with a ratio to give 115 secondary volts at normal pri·

mary volts may be used as a source of potential for the regulator.

High tension fuses, with current limiting resistances where sys·

tem requirements indicate they are needed, are recommended

for use in the primary side of the transformers. This is desirable

in order to isolate the transformers from the bus in case of high

tension winding faults. No secondary fuses should be used.

There should not be any other load on the potential transformers

used with the regulator, unless as shown on the speCific diagram

furnished with the equipment. With regard to the a-c volt-meter

usually supplied as a part of the switchboard control equipment

for voltage indication purposes, this may be connected normally

to any one of the a-c machine phases. In cases of appreciable

phase load unbalance it should be remembered that the usual

single phase voltmeter does not indicate the average a-c three

phase voltage to which the regulator responds.

@ CURRENT TRANSFORMERS

Current transformers are required for cross-current compen·

sation purposes in connection with the parallel operation of

regulators or when it is desired to provide for line drop com­

pensation. These transformers may be used with indicating in­

struments in addition to the regulator but their use with walthour

meters is not recommended as the regulator load may introduce

some error in the readings.

For cross-current compensation on three-phase, three-wire sys­

tems, one current transformer is required for each a·c machine

and its regulator. The primary rating is determined by the full·

load current of the generator multiplied by the factor 1.25.

For line·drop compensation the number of current transformers

required is dependent upon the individual requirements of each

particular application. The primary rating of each transformer

should be selected equal to the normal full·load current of the

circuit to be compensated, multiplied by the factor 1.25 and the

nearest standard ratio selected.

Where the current limiting device is used one standard current

transformer is required and selected according to the normal

full load current of the machine to be protected, multiplied by

the factor 1.25.

In all cases current transformers of sufficient capacity should

be supplied so that the volt·ampere burden of the devices con·

nected to them does not exceed their rating as specified by

their manufacturer.

Sensitivity

The rated sensitivity of the Type BJ·30 regulator is plus or

minus one·half of one per cent of normal voltage. The

rated sensitivity represents the band or zone of voltage,

expressed in terms of percentage of the normal value of

regulated voltage, within which the regulator will nor­

mally hold the voltage under steady load conditions. When

the regulated voltage varies more than the percentage sen·

sitivity from the regulator setting, due to sudden changes in

load or other conditions, the regulator will immediately

apply corrective action to restore the voltage to the sen­

sitivity zone.

Regulator sensitivity should not be confused with overall

regulation, which involves not only regulator sensitivity but

also the time constants of the machines, and the character

and magnitude of load changes. The magnitude and rate

of load change determines how far the voltage will vary

outside of the regulator sensitivity zone and the time con·

stant of the machines chiefly determine the time required to

restore the voltage to the sensitivity zone of the regulator.

For these reasons, only sensitivity can be specified insofar

as the regulator is concerned, rather than over·all regula·

tion which involves factors over which the regulator has no

control.

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Operation

I +_4>-,C_u _rr_e_ n_1 _Ir_o_o_s-" 2�--��----��� 3�'---+--r-�--�-4� HI. fuses

Grd,

cs CS RI RI

Rectox recli fiers

Test link

on contoctor

panel

NOTE*-Current Transformer and

Cross .. Current Compensator Re ...

quired When Application Involves

P arallel Operation.

Symbols 1 Open contact

Closed contact Ope rating coil of device Indicating lamp

Resistor

Rheostat

Conde nser Rectax rectifier

K oi Ie switch

A-C gen field

rheo ,

Pilot exc,

Diff fld res,

Pilot exciter field rheostol

shunt field

Pilot exciter field series field �eg'COil

Te�nk I

Knife switch

QH

I I

I I

I ------ �

BJ -30 Regulator e lement (Front view)

Main exc rheo, motor

Res,

Rheo, limit switches

CS RI

Res ,

CS CS ReI} MI

Device Nomenclature

DEVICE

R·L AR-AL NR·NL QR-QL QH-NH CS-R � CS-L j CS-Reg. CS-RI CS-MI RL-LL CP MG

DESCRIPTION

Regulator Element Raise and Lower Normal Response Contacts. Regulator Element Raise and Lower Quick Response Contacts. Raise and Lower Rheostat Motor Control Contactors. Raise and Lower High Speed Field Forcing Contactors. Anti-Hunt Devices for Regulator Quick and Normal Response Contacts.

Rheostat Control Switch (Manual) Raise and Lower Contacts.

Regulator Cutout Contacts Closed in "Reg." Position Only. Regulator Cutout Contacts Closed in "Reg." and "Ind." Positions. Regulator Cutout Contacts Closed in "Man." and "Ind.'t Positions,; Raise and Lower Indicating Lamps. A-C Undervoltage Relay Auxiliary Relay

(+l

CP D-C

contro l bus

CP

(-)

Fig. I-Schematic wiring diaqrarn of Type BJ -30 generator voltage regulator for oontrol of an a-c generator excited by a main exciter which is

separately excited from a pilot exciter. Current transformer and cross .. current compensator shown are required only when two or more a-c gen­

erators, under control of individual regulators. operate in parallel, Lines in red are added to provide "Loss of Potential" protection.

The main control element of the regulator is energized from two

single phase potential transformers connected to the a-c machine

leads. There are two sets of contacts on the movincg lever arm

of the regulator element: the "normal response" contacts R·L

and the "quick response" contacts AR·AL. The normal response

R-L contacts control the rheostat motor contactoTs NR and NL,

to raise or lower a-c machine voltage. The quick response AR

and AL contacts control the high speed contactors QR and QL,

which are the field forcing and field reducing contactors re­

spectively. When OR is closed all external resistance is shorted

out of the main exciter field circuit and when OL is energized

a block of resistance is inserted in the field circuit. www . El

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NORMAL RESPONSE

When the a-c voltage is normal, the regulator lever arm will be balanced and in this position neither the normal response con­tacts R-L nor the quick response contacts AR-AL will be closed. Both indicating lamps LL and RL will be brightly lighted.

Should the a-c voltage fall below normal by a small amount, depending upon the sensitivity setting of the regulator, the nor­mal response contacts R will close, energizing the rheostat motor control contactor NR. The contacts on contactor NR complete the circuit to the motor of the main exciter field rheostat. The motor then turns the rheostat in a direction to cut resistance out of the exciter field circuit which increases the voltage applied to the exciter field circuit.

The rheostat motor control contactor NR has three contacts which close in independent circuits simultaneously. The one circuit is that just described which operates the rheostat motor. The second is the circuit of the anti-hunting winding NH of the regulator main control element and the third set of contacts on contactor NR complete the timing condenser circuit. The anti­hunt device operates to increase the gap distance between the contact faces of the regulator contacts R and L, thereby opening the circuit at the R contacts. This change in position of the R contact is equivalent to changing the regulator setting to a lower voltage, so far as the R (raise) contacts are concerned (and to a higher voltage so far as the L (lower) contacts are concerned.) This change in regulator setting or calibration is the anti-hunting effect and it can be varied to suit the individual characteristics of different types of a-c machines.

Where the deviation from normal voltage is small and within the recalibration effect of the anti-hunt device, the immediate re­sults of the closing of the contacts on contactor NR is to cause the opening of the regulator R contacts, which in turn opens the circuit to the coil of contactor NR, to stop the motor of the ex­citer field rhEostat and thus stop the rheostat moving arm. How­ever, contactor NR does not immediately open due to a time delay circuit around its coil. Thus, the rheostat arm is permitted to move a definite distance, for example, from one button to the next on the rhEostat faceplate. At the end of its time delay, contactor NR opens to stop the rheostat motor and de-energize the anti-hunt device.

After the rheostat motor stops, it is desirable to provide some time delay to allow the a-c machine voltage to reach its final normal value. Such delay is obtained by means of a dashpot on the anti-hunt device, which prevents the regulator contacts from immediately returning to their normal position. After this time delay has passed and the contacts have returned to their normal position, the normal response contacts R will again close if the a-c voltage has not returned to normal. This will start another cycle of operation such as just described and these cycles will continue until normal a-c voltage is established.

Where the original voltage deviation is large enough the reg­ulator contacts will make continuously even though the anti­hunt device changes the contact setting. In this case the reg­ulator lever arm is caused to follow up the change in contact position made by the anti-hunt device, and the R contacts and contactor NR will remain closed. This causes the rheostat motor to run continuously until the a-c voltage gets within the zone for which the anti-hunt device is set, at which time notching action as previously described will take place to bring the volt­age to normal.

By means of the continuous or notching action of the rheostat, dependent lIlp!Jn the magnitude of the voltage change, time is allowed as the voltage approaches normal, for the machine to settle betwekn each voltage correction. The action of the dash­pot is also such that the time required for contacts to remake is

longer as the lever arm approaches the normal voltage position. In other words, the time that the motor is de-energized, is an increasing ratio as normal voltage is approached. This results in a decreased motor speed as the rheostat arm moves nearer to its new position. Thus overshooting of the rheostat position is prevented and the voltage is brought to normal in a minimum length of time.

The foregoing discussion covers deviations in voltage lower than normal. Where the voltage rises above normal the regulator normal response contacts L will close, energizing the rheostat motor control contactor NL, which in turn operates the rheostat motor to increase the resistance in the exciter field circuit. At the same time, contacts on contactor NL energize the anti-hunt device NH to spread the contacts and de-energize the rheostat motor contactor as previously described.

QUICK RESPONSE

When a large drop in voltage occurs, such as might be caused by a large block of load being thrown on the system or by a fault, the normal response contacts R on the regulator close, followed by the closing of the quick response contacts AR. Con­tacts AR close the circuit to the high speed field forcing con­tactor OR, which short circuits all of the external resistance in the exciter field circuit, thus applying full exciter voltage to the field circuit. This causes the a-c machine voltage to start to return to normal very rapidly.

When the field forcing contactor OR closes, an auxiliary con­tact on this contactor closes at the same time in the circuit of the anti-hunt device OH. This device operates to spread the AR and AL contacts, in the same manner as described for the NH device and the R and L contacts. Therefore, if the deviation from normal voltage is within the recalibration effect of the OH anti-hunt device, the field forcing contactor will close and open rapidly while the rheostat arm approaches the required new position. If the deviation from normal voltage is greater than the recalibrating setting of the OH anti-hunt device, the field forcing contactor will close and remain closed until the volt­age is brought within the setting the anti-hunt device.

When the a-c voltage gets within the setting of the AR contacts, the normal response contacts R take control and by notching the rheostat, return the a-c voltage to normal. Since the rheostat turns at maximum speed while the quick response contacts are closed it takes only a minimum of additional movement after the normal response contacts take controL to return the volt­age to normal.

In a similar manner, when a large block of load is removed from the system, thus causing a large increase in voltage, the quick response contacts AL will close and energize the high speed field reducing contactor OL, whose main contacts are normally closed. This contactor then opens its main contacts and inserts a block of resistance in the exciter field circuit, causing the exciter voltage to fall with extreme rapidity and in turn the a-c machine voltage falls very rapidly. When the a-c voltage gets within the setting of the quick response contacts AL, the normal response contacts L take control and settle the voltage by notching action of the rheostat.

LOSS-Of-POTENTIAL PROTECTIVE EQUIPMENT

To insure against over voltage on the generating system, should the potential to the regulator be interrupted, a type CP a-c under­voltage relay may be used to actuate a type MG doc relay to block the BJ-30 _ regulator "raise" circuits. The connections of such a set of loss-of-potential protective equipment, consisting of two relays and a resistor, is shown in red on Fig. I. This equipment can be furnished with the regulator, and is applicable specifically to turbogenerator installations. www .

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Cur I��-�----���-�--�

24-+-�--------���-1 34-+-��-------+-+-/

Step· up current aula t ransformer

Rectox reclifiers

CS RI

Motor oper. main�

exc. rheo. C ndsr.

Pilol exc. series fld.

(+)

D-C control

bus

cs CoZ�Clor I C d

NR

panel n sr. � __ + __ --l L-__ -+ ____ -. L

Symbols

1 Open contact

Closed contac!

Operating coi 1 of device

Indicating lamp

Resistor

Rheostat

Condenser

RecIo. rectifier

Knife switch

CS Rl

CS Ml

Device Nomenclature DEVICE DESCRIPTION

R·L AR-AL RI-LI ARI NR-NL QR-QL QH-NH RH-LH

CS-R 1 CS-L f CS·Reg. CS-RI

CS-MI

RL-LL RC-LC SC CV MG

Regulator Element Raise and Lower Normal Response Contacts. Regulator Element Raise and Lower Quick Response Contacts. Current Limiting Element Raise and Lower Normal Response Contacts. Current Limiting Element Quiclr Response Contacts. Raise and Lower Rheostat Motor Control Contactors. Raise and Lower High Speed Field Forcing Contactors. Anti-Hunt Devices for Regulator Quick and Normal Response Contacts. Anti-Hunt Devices for Current Limiting Element Quick and Normal Response

Contacts.

Rheostat Control Switch (Manual) Raise and Lower Contacts.

Cutout and Indicating Switch Contacts Closed in "Reg." Position Only. Cutout and Indicating Switch Contacts Closed in "Reg." and "Ind." Positions

Only. Cutout and Indicating Switch Contacts Closed in "Man." and "Ind." Positions

Only. Raise and Lower Indicating Lamps. Raise and Lower Anti-Hunt Auxiliary Relays on Current Limiting Element. Overcurrent Relay. Timing Relay. Auxiliary Timing Relay.

Fig. 2�Schernatic wiring diagrarn of Type EJ .. 30 generator voltage regulator for control of a synchronous condenser excited by a m.ain exciter

which is separately excited £rom a pilot exciter. Diagrarn shows the current liITliting device and associated auxiliary relays recommended for

this type of application. www . El

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OPERATION WITH SYNCHRONOUS CONDENSERS

The Type BJ-30 regulator may be used with a synchronous con­

denser to maintain constant voltage on a transmission line by

varying the condenser field excitation. When the excitation of

a synchronous condenser is increased above normal it fur­

nishes a leading current to the line, thereby causing the volt­

age to rise. In a similar manner, decreasing the excitation

lowers the voltage. Thus, when a generator voltage regulator

is applied, it will hold the line voltage constant by varying the

excitation of the synchronous condenser, provided there is suf­

ficient corrective kva capacity in the synchronous condenser.

When a synchronous condenser is used for transmission line

voltage regulation, it is ollen necessary that it furnish not only

leading kva but also at times lagging kva. In order to supply

lagging kva the excitation of the condenser must be reduced to

an extremely low value. In fact it is sometimes necessary to reo

duce the exciter field excitation almost to zero. In such cases,

where it is necessary for the exciter to operate at less than 30%

CURRENT LIMITING DEVICE WITH DELAYED ACTION

In the operation of a synchronous condenser under abnormal

conditions a situation may occur where the condenser does not

have sufficient corrective kva capacity to handle all, or the

most severe, system requirements. At such a Hme, the regulator

in trying to hold up line voltage, would so over excite the con·

denser that it would draw excessive current and become over·

heated. To protect against this condition, a current limiting de·

vice has been designed for use in such cases. This same device

may also be employed where the regulator is used with an a-c

generator, with a·c generator being subject to over-current

which might result in damage to the a-c machine if maximum

excitation was maintained too long.

The current limiting equipment consists of a current limiting

element and three auxiliary relays, which consist of a type SC,

type CV and type MG relay, connected as shown in Fig. 2. The

current element has its contacts connected in series with the

main control contacts of the voltage regulator so that when the

load current increases, the current element takes control to pre·

vent a further increase in excitation. When the load conditions

change and the current drops below the setting of the current

element, control is restored to the voltage regulator.

The current limiting equipment has been designed to recognize

two conditions; first, the case of slowly rising load current to a

predetermined limiting or unsafe value, and second, a sudden

increase in load current such as might be caused by a fault or

short-circui!. The distinction between a slowly increasing over·

load and a sudden overload is made by a type SC curren! relay,

which is set to pick up at a current somewhat above the regulat.

ing point of the current limiting elemen!.

In the first case, for slowly rising load current, where the current

limiting element takes control from the voltage regulating el.

ement during the period of overload and returns control to the

voltage regulating element when the overload has passed, the

following sequence of operation takes place. Referring to Fig.

2, the current limiting contacts Rl open the circuit to and take

the control away from the R contacts of the voltage regulator

of its rated voltage, this requires that it be separately excited

from a pilot exciter or other source.

In order to seCure low or reversed field excitation, the exciter

must be equipped with a suitable differential field winding. The

differential field is energized in the opposite direction to the

main shunt field and has enough effect to reverse the exciter

voltage a small amount. Where the differential field scheme is

used the simple series type of motor operated main exciter field

rheostat is recommended. If the differential field scheme is not

used it is possible to use an alternate arrangement consisting of

some special form of exciter rheostat such as a potentiometer

type, or Wheatstone bridge design. In the latter rheostat, two

opposite arms of the bridge are fixed and the other two are va­

riable, the variable arms having sufficient resistance to balance

the bridge and reduce to zero the voltage applied to the exciter

field.

element. Contacts Ll of the current limiting element then close

to energize the circuit to the rheostat motor control contactor

NL, which in turn causes the excitation to be reduced until the

load carried is the desired value. In this sequence of operation

only the "normal response" circuits of the voltage regulator are

used.

In the second case, where a sudden overload occurs, quick re­

sponse excitation may be required. Contacts ARI of the cur·

rent limiting element operate in conjunction with the quick reo

sponse contacts AR of the voltage regulator in the same manner

as described for contacts Rl of the current limiting element with

the normal response contacts R of the voltage regulator. The

sequence of operation is initiated by the type SC current relay

opening its contacts. One set of these contacts de-energizes the

type CV timing relay and the other set de-energizes the type

MG auxiliary relay. With the type MG relay in the de·energized

position this permits the contacts of the voltage regulating ele­

ment to remain in control for the time setting of the type CV

timing relay, thus providing the use of both the normal and quick

response excitation for stability purposes under fault conditions.

The time element may be varied from about one second to sev·

eral seconds. At the end of the time setting, the timing CV relay

contacts energize the type MG auxiliary relay, which in turn

removes control from the voltage regulator and transfers the

control to the current limiting element.

When the sudden overload is past, the type SC current relay

resets, in turn closing the circuit which maintains the type MG

auxiliary relay energized and at the same time closing the cir­

cuit which resets the type CV timing relay. Should the decreas·

ing overload remain for a time at a value below the pickup of

the SC relay but within the setting of the current limiting ele­

ment, the lalter will maintain control to prevent increase in ex·

citation. When the overload falls below this value, the contacts

RI and ARI cf the curren! limiting element return to their normal

closed position thus returning complete control of the voltage

to the voltage regulator. www . El

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PARALLEL OPERATION

Slation bus I�--------------------�----------------

2 -4�------------------4-�--------------3 �-+�----------------�-+�-------------

A - C Generator No.1

'/ Voltage regul alor No. I

A-C Generator No.2

Voltoge regulator No.2

Veclor Diagram

I2 O"loP.F.

C

!

�Y2 i Compensator Int ernal Diagram

Fig. 3-Diagram of connections for cross-current compensation when awe generators operate in parallel, each under control of an individual

regulator. Vector diagrarn and internal wiring diagram of compensator show compensating voltages supplied by compensator to regulator.

The Type BJ-30 regulator can control only one exciter at a time.

Where two or more a-c machines are operated in parallel, each

provided with an individual exciter, it is necessary that each one

be provided with its own individual regulator. With this scheme

of operation the exciters must be operated non· parallel.

The division of the kw load among paralleled a-c generators is

dependent upon the power supply to each generator and is

controlled by the governor of its prime mover. Thus the divi.

sion of the kw load is practically independent of the excitation.

However, changes in the field excitation of paralleled a-c mao

chines does affect the reactive kva or waltless component of

the output. Since the voltage regulator acts directly on the field

excitation, it will be seen that although the division of kw load

between machines is unaffected by the voltage regulator, the

division of wattless current is directly affected by the operation of the regulator.

Thus, when a-c machines are operated in parallel, each under

control of an individual regulator, this will cause circulating

wattless current between the a·c machines unless some pro·

vision is made to cause each machine to shirk wattless current.

To secure stability in parallel operation it is, therefore, necessary

to give the regulated voltage a droop with increase in the walt·

less component of the machine current. In general, a satisfac.

tory droop in the regulated voltage will be obtained if there is

from four to six per cent reactive drop between two a·c machines.

This reactive drop may be either in the form of a power trans·

former bank or where the station layout does not provide such

an arrangement, it may be obtained artificially by giving the reg·

ulator a drooping characteristic from a cross-current compen·

sator energized from a current transformer.

Where the cross current compensator scheme is used, one com·

pensator and one current transformer is required for each a·c

machine and its regulator as shown in Fig. 3. The compensator

is designed to supply compensating voltages in two legs of the

three·phase regulator potential circuit. This insures applying

a balanced three-phase voltage to the regulator element, which

would not be the case if only one leg was compensated.

In the vector diagram, Fig. 3, the potential transformer secondary

voltages on the regulator are represented by vectors E1.2, E2.3 and E3-1. The current applied to the auto·transformer in the

compensator is taken from the secondary of a current trans­

former located in phase 2. Two compensating voltages are pro­

duced, one between terminals XI-X2 designated as Ez on the

vector diagram and the other between terminals Yl-Y2, desig­

nated as ER on the vector diagram. Voltages ER and Ez are 1200

apart in time phase and, therefore, can be added to another

three-phase voltage without unbalancing it.

By referring to the vector diagram it will be noted that Ez and

ER are shown for zero power factor at which condition maximum

compensation is obtained. As the power factor approaches

unity these vectors swing through an arc of 90° and give zero

compensation at 100% power factor. At zero power factor vee·

tors Ez and ER add directly to vectors EI-2 and E3-1 respec·

tively. For power factors greater than zero only a proportionate

component of these voltages Ez and ER add directly to voltages

El.2 and E3-1. The addition of these compensating voltages to

line voltages EI.2 and E3_1 as the load increases or the power

factor changes gives the regulator element a high voltage indi­

cation, resulting in a reduction or droop in regulated voltage.

Usually the compensator should cause from 4% to 6% droop in

voltage at zero power factor full load. The compensator is de·

signed to give 12% of 115 volts compensation, on the maximum

dial setting, when 4 amperes are flowing in the current trans·

former secondary. It is not necessary to use all of the 12 % com·

pensation, however, the 4% to 6% values mentioned above

usually being sufficient for good parallel operation. www . El

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LINE DROP COMPENSATION

Phase rota lion 1 - 2 - 3 .

� __ '

_

Ja

_

Od

_

{di� 3 -I---��-+-+_+-----./

o I 2

CROSS CURRENT

CO G REACTANCE LINE DROP

XI X2 VI

Ex ....

REACTANCE L I N E DROP

Y2

Ev -

co c RESI STANCE LINE DROP

XI X2 YI Y2

Ex �

R ESISTANCE LINE DROP

12 E coil' -Ex +E23 - Ev

Fig .. 4-External connection diagram. for Type BJ compensators�

Outgoing line 10 load center

Current transformer

Voltoge regulator

Vector d iagram

Fig. 5-Line drop compensation diagraln for one a-a generator and

single outgoing line.

The wide use of interconnecting power systems has eliminated to a large extent the need for line drop compensation. How­ever, it is sometimes desirable 10 regulate for a conslant voltage 10 he maintained at some point on the system external to or dis·

lant from the station where Ihe a-c machine and its regulator are located. The principle by which this is accomplished is shown by the vector diagram of line drop shown in Fig. S.

EI is the station voltage, E2 the feeder terminal voltage or the voltage at the load center, HI is the ohmic drop of the line and Xl the reactive drop. If it were possible to supply the regulator with pilot wires running back from the end of the line, it would receive the voltage E2 and could adjust the excitation of the generator to maintain E2 constant. Since in actual practice it is impractical to run pilot wires, the regulator potential winding is energized from the generator bus voltage, that is, by EI, and the two components Xl and HI are subtracted from it artifi. cially by the compensation, so as to supply the regulator with a resultant voltage E2. In this manner the regulator acts the same as if it were energized by pilot wires from the end of the trans­mission line, provided the components HI and Xl are actually proportioned to and in phase with the corresponding values in the line.

In general, since the reactance component Xl of the transmission line predominates, it is necessary to compensate mainly for this component of the line drop, the resistance component HI having a relatively small effect. In the following typical examples the compensation for the reactance component only is discussed. However, for those applications where compensation for the re­sistance component is also desired, such compensation can be included.

For those cases where system operating requirements will per­mit or favor the use of line drop compensation, the scheme of compensation to be used can be selected only alter a careful analysis is made. The following information is required and should be supplied in connection with any given application in order that recommendations covering proper equipment may be made.

1. The approximate regulation of transmission line, at its rated capacity and zero power factor.

2. Length of transmission lines. 3. Wire spacing. 4. Size of wire. S. Frequency of system. 6. Total capacity of transformer banks at each station that oper-

ates on the line.

For the first example, refer to Fig. 5, which shows the connec­tions for line drop compensation when used with a single a·c generator which feeds a single transmission line. By means of one current transformer and a suitable line drop compensator, a voltage component is introduced into the regulator element potential circuit which is in proportion to the reactance drop to the load center at the far end of the transmission line. The com­pensator functions to lower the voltage impressed on the regu­lator main control element as the station load is increased, thus causing the regulator to maintain normal voltage at the load center at the end of the transmission line.

The next example is shown in Fig. 6. In this case it is desired to make several a-c machines, each controlled by an individual regulator, operate in parallel and yet have the station bus volt­age increase with both kw and reactive load. It is in this phase of line drop compensation that many different schemes are avail· able. However, whatever scheme is used must include pro· vision to prevent interference from the cross-current compen­sation. For example, where a slightly rising bus voltage is de· sired, line drop compensation can be used in conjunction with the cross-current compensation required for parallel operation, provided all the individual line drop compensators are operated

continued on page 14 • www . El

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LINE DROP COMPENSATION­Continued

from the totalized secondary current of

current transformers, so connected that

they carry the entire load of the station.

The example shown in Fig. 6 is pre­

sented as a typical case and requires

the use of one current transformer, one

cross-current compensator and one line

drop compensator with each a-c ma­

chine and its regulator. No changes

in line drop compensator setting or cur­

rent transformer secondary connections

are necessary when an a-c machine is

removed from the system, providing the

number of outgoing feeders remains

unchanged. Any change in the num­

ber of outgoing feeders changes the

system impedance and thus requires

readjustment of the setting of the line

drop compensators.

� ____ �----__ ----------------_S�t a�r�io�n�B�u�s--�------------------------------ 1 2 2 3 3

C u r re n t Iran sformer

Gener a tor No. 1

Cross currenl leom pensa tor I

2

L i n e drop 'compens a to r

Vol l a g e regu l ator No. 1

Current tran sfor m e r

/

Cross c u r r e nt c o m p e n s a t o r

/

2

L i ne drop compensator

transform ers Vol t a g e r e gulator N o . 2

Generator No. 2

Fig. G-Line drop and cross�current compensation diagram for paralleled a-c generators.

PILOT �EXCITER OVER-VOLTAGE PROTECTIVE EQUIPMENT

A- C Generator

Generator f ie ld

Motor operated rheostat

On applications involving water-wheel driven a-c generators with the main exciter separately excited from a direct connected pilot exciter,

there is danger of excessively high pilot exciter voltage if runaway con·

ditions should be encountered in operation of the unit.

Main excit e r

f Main exciter shunt field

Pilot exciter

Pi lot exciter shunt field

p __ �C�o�nt�r�o�l �b�us� __ �_ N ---_--+_

I I

Voltage � ';:--6...!--+6-t�)r-o-+, sensit ive I relay

To alarm

circu i t Protective resistance

Pilot exciter

field rheostat

Fig. 7-Pilot-exciter over-voltage protective equipment diagram .

CONTROL VOLTAGE

The protective equipment consists of a voltage sensitive relay, an auxil­

iary contactor and a protective resistance, as shown in Fig. 7. The con· tacts of the voltage sensitive relay are normally open and are adjustable so that they may be set to close when the pilot exciter voltage reaches a

predetermined value above normal. Operation of the voltage sensitive relay on over-voltage energizes the auxiliary contactor, causing it to open its normally closed main contacts and insert the protective resist­ance in series with the pilot-exciter field. This limits the voltage to a safe value while runaway speed conditions exist on the unit.

When the auxiliary contactor is energized it electrically locks in that

position through one of its auxiliary contacts_ When the speed returns to normal and the voltage drops, the voltage sensitive relay contacts

return to their normal position and in so doing cause the auxiliary con­

tactor to be de-energized by means of a shunting down circuit. In this

manner the protective equipment is automatically reset to normal. This

scheme of protection is independent of the voltage regulator, which op­

erates automatically to protect the a-c generator and its main exciter

from over-voltage.

A separate source of doc power is required for operation of the

exciter rheostat motor and certain parts of the regulating equip­

ment, as shown in Figs. 1 and 2. This doc power may be obtained

from the station battery or other reliable doc source. Where the

main exciter is separately excited from a pilot exciter it is prefer-

able to obtain the doc power from the pilot exciter, since the

pilot exciter is independent of any load except the field of the main exciter. The rheostat motor and regulating equipment

draws approximately 3 amperes intermittently and are designed

for operation from 125 or 250 volts doc. www . El

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Dimensions in inches

Approximate only. Do not use for construction purposes.

Typical Steel Panel Layouts

II j

18

4tJ t -90 /1

51 7 2 ,

I 35

I I

_ _ _ -.1

r-2

[if � . ! . I I I • '

'-ll

7 .J..J-J I - �

l$J ... -t

� 8 � ro- 16

Steel panel ( E bony asbestos or slate

panel may also be u sed )

Type BJ - 30 moin control e lement in proje c t ion type case

Indicating

Nome p l a t e

VOltage adjusting r h eo stat �.,. {Manua l l y operotedl

�/:;�

/> 'if Transf e r switch / 2 16 /

/ Exciter rheostat control switch

Cross c u rrent compensator (Required when appl ication

involves par a l l e l operat ionl

// Terminal block I

/ Channe I iron bose

Rectox unit

43 84

3 - -+ 7iS I"'� 9

.. i y! �91 �t�

8

Type BJ-30 regulator equipment on steel panel. Main control ele­

ment is shown with projection case.

Typical Motor-Operated Rheostat Assemblies

High speed f i e l d forc ing contactors

F i e l d forcing res istors

J,

NOle : Top, back S bottom of f ronl are of perforated metal screen

Cubicle type assem.bly of regulator contactor panel and plate-type

m.otor-operated rheostat for medium size exciters.

T 12

�f 16

t

2

Steel pan e l (Ebony asbestos o r

slate pa net m a y a l so be used)

Vollage adjusting r h eostat (Man ually operated)

Channel iron base 8 Type BJ ... 30 regulator equiprn.ent as used with synchronous condens�

ers. Main control and current limiting elements are shown in flush

type case.

High speed f ie ld forcing contactors

Combined assembly of regulator contactoL" panel and faceplate type

motor .. operated rheostat for large size exciters. www . El

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Data Sheets for Generator Voltage Regulators

Complete data on generator, excitation, load, etc. must be sup·

plied to determine the size and type of motor· operated main· exciter field rheostat and other apparatus required. This infor·

mation should be supplied on Westinghouse Form 1046, copies

of which are available through your Westinghouse office or

representative.

D AT A SHEET F O R V O LTAGE REGULATOR (I NFORMATION REaUIRED I N A D O I T I ON T O MACHr",r:: OAtAJ

P1JReHASEA� ___ � __ ... __________ 'OIlOER HO.

MACHINES

1, Indicate aaiure oj the load on d'C generator: Lighting . Motor,.

(Ii is important 10 note the charader of any load causing serious voltage *2. Will the a-c generator operate in paraUel with any othet a·c

generator? . . . . . . . . . . . . . . . , . , (U SO, cross curren! compensalion and a current IransIormer may be {Excilers must operate non-paralleL)

3, If speed variahon is greater than ± 5%, range. *4, Is the d·c generator sell or separately

5. Wlll the d,c generator operate shunt, or compound? .

(When controlled by a voltage regulator, Ihe exciter shou'd be shunt or

REGULATOR

6. Is regulator 10 be dupncale of, or 10 match up wilh a previous order':--.-� i Ii so, give order number. . '

{Avoid ordering "dupllca!e" regula lor unless machines have the same �7. Is regulafor required for projection or semi·llush mounting?

(The SRA�D·Jr and SRA·D· 1 are not ava.lable for flush mounting,) 8. Is bracket moun�ing required? .

Ii so, give type 01 !rame: steel, 9. Indicate if installalion will De

a lroplea' 10.

1 1 . panel on H..->gulalor order? If so, slale Pdnel; height .

12. I s compensation for line drop required?

thk:kness. beveL . ' hame .

% Reactive? (:� Resistive?

13, Is the voltage rheos131 required for separate mounting? .. give panel !hickness,

14, Give range in vcllage ad;usting rheostat, i:! 15. Give d::J.y spccidl requirements [or sellsil:vlly

from published values . (Nole that s3nsitivily b:Her than the value publtshed in lhe Ga:r.erator Dala lor machine rating: and conespond .ng class 0.1 regulator, may regulator)

Hi U oil cut·out or lrans!er switch is included in the order give panel ihickness . .

• Minimum requirements.

WHTIHCMOU5E 1'0rtM Hue a­li. SHEETS�$HE.ET l

Literature Reference

• PRICES-Refer to Price List 56·320

DATA S H E ET F O R V O LT AGE R E G U L AT O R S

PI.HtCItASER ..

A. C. MACHINE

1. Manufaclurer .. ___ .. �� ___ .. �_

Serial No. or 2. Mfgr's Order No.

3. Shop Order No, ,

4. Kva Capacity , , .

Rated Volts, S. Ph.ase-lo·Phase . .

6. Raled Speed

7. 1, 2 or 3 pr.as,�

B. Frequency

fIeld 9. Resistance at 75"'C.

Generator or condenser hek1 excilalion at no load and nor­mal A·C operallng voltage;

10. Field Volts

1 1 . Field Amps, .

Generalor o r condenser held el!::citallon under mdl(lmum con­dItions;

12. Field Volts

1 3 F1C!d Amps.

14. Xva Load .

15 Type of Drive . .

Regulation 16. Movers .

17.

Give any special condition such held ampere, and vol!:! on

or Conden�r which under-excited:

Field Volts . . " .

Field Amps . . . . . . . ______ _

Wlt$TIN(;HOUS£ FOAM IOU I" r SHEETS-SHEET I

EXCITER OR O. C. GENERATOR

18. Mdnulactu,e, __ _ .. . __ . __ ...

19.

20.

2 l .

22.

23.

24.

25.

26.

27.

No. or Order No

Shop Order No. ,

Type .

Kw Capacity .

Hated Voltage

Rated Speed ,

excIter wllhoul

SATURATION CURVE OATA

NO lO�O ON UC!TfR

Shunt Field Amps. at-

28. rated exclter volfs . 29. faled exciter valls . 30. rated excifer volts . . _______ .

3 1 , exciler volts ��_& Amps,

32.

fULL lOAD ON ElClTER

taken at constant cur� cons!anl resislance

Data taken shun! or compound? .

Shullt Field Amps. at--

34. 100% raled volts , 35. Max. e:xciter vO"' � _ __ .• "'mp" . __ .�_

EXCITE. fiElD RH,[OSTi\.T

36. Variable Resistance . • . . _____ _

37. fi%:ed Resistance.

Type of 38. Drive for £x:dter . . . ,

Speed Regulation 01 39. Exciter Prime Mover

• SILVERSTAT Dl RECT·ACTlNG REGU LATORS-Small size a-c and d·c generators-refer to Descriptive Bulletin 56-350

Medium size a-c and d·c generators-refer to D�scriptive Bulletin 56·351

W E S T I N G H O U S E E L E C T R I C C O R P O R A T I O N EAST PITTSBURGH PLANT • POWER CONTROL AND COMM. DEPT. • EAST PITTSBURGH, PA.

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