41-102.1b com overcurrent relay · 2018-05-10 · 41-102.1b com overcurrent relay 6 the tap screw...

41-102.1B COM Overcurrent Relay

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COM Overcurrent Relay 41-102.1B

3

Figure 3 :Time Overcurrent Unit (Front View) 1. Tap Block 2. Tap Screw3. Time Dial 4. Control Spring Assembly & Moving Contact5. Disc 6. Stationary Contact Assembly7. Magnetic Plugs 8. Permanent Magnet

Figure 4 :Indicating Instantaneous Trip Unit (IIT)1. Tap Block2. Tap Screw

Photo needed here

Sub 19664A31Photo

Sub 19664A36Photo

1 7 2

3

6

4 5

8

1

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Figure 5: Indicating Contactor Switch (ICS).

2.2 INDICATING CONTACTOR SWITCH UNIT(ICS)

The dc indicating contactor switch is a small clappertype device. A magnetic armature, to which leaf-springmounted contacts are attached, is attracted to themagnetic core upon energization of the switch. Whenthe switch closes the moving contacts bridge two sta-tionary contacts, completing the trip circuit. Also dur-ing this operation two fingers on the armature deflect aspring located on the front of the switch, which allowsthe operation indicator target to drop.

The front spring, in addition to holding the target, pro-vides restraint for the armature and thus controls thepickup value of the switch.

2.3 INDICATING INSTANTANEOUS TRIP UNIT(IIT)

The instantaneous trip unit is a small ac operated clap-per type device with tapped coil. A magnetic armature,to which leaf-spring mounted contacts are attached, isattracted to the magnetic core upon energization of theswitch. When the switch closes, the moving contactsbridge two stationary contacts completing the trip cir-cuit. Also, during the operation, two fingers on the arma-ture deflect a spring located on the front of the switchwhich allows the operation indicator target to drop.

A core screw accessible from the top of the switchprovides the adjustable pickup for each tap range.The minimum and maximum pick-up points are indi-cated on the scale which is located to the rear of thecore screw. The setting range for the IIT unit is 6-144amperes.

2.4 SSC-T

The SSC-T unit consists of a small input transformer,printed circuit module, and output relay. The printedcircuit module (refer to figure 22, page 29), containsrectifying and filtering components for level sensingand for a power supply to operate the sensing circuitand the telephone type output relay. (See locationdrawing figure 21, page 29.)

For overcurrent detection, transistor Q2 is normallynot conducting and the telephone relay is deener-gized. Transistor Q1 is used as an emitter follower.When ac current is applied to the primary of thetransformer, a voltage is produced on the secondaryside that is proportional to the input. Rheostat (R2) isfor the pick-up setting. When voltage from rectifiersZ1, Z2, and capacitor C2 exceeds the breakdownvoltage of Zener diode Z5, the Zener diode conductsto turn on transistor Q2 and operate the telephonerelay (SSC-T Relay) per schematic of figure 17, page25.

Sub 19664A45Photo


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2.5 AUXILIARY TIME-DELAY UNIT (T)

This slugged telephone type unit, in conjunction witha tapped resistor, provides a 5-6 cycle delay onpickup. The resistor in the front of the relay is tappedfor use with 24, 48, 125 or 250 volt dc supply, asshown in the internal schematics of figures 15 & 16,page 23 and page 24.

3.0 CHARACTERISTICS

3.1 TIME-OVERCURRENT UNIT (CO)

The relays are generally available with CO units inthe following current ranges:

The time vs. current characteristics are shown in fig-ures 6 to 12 (beginning on page 14). These charac-teristics give the contact closing time for the varioustime dial settings when the indicated multiples of tapvalue current are applied to the relay.

3.2 IIT UNIT

Time of operation of the IIT unit at twice pickup is 35milliseconds or less.

3.3 OVERCURRENT RELAY SSC-T

3.4 TRIP CIRCUIT

The main contacts will safely close 30 amperes at250 volts dc and the seal-in contacts of the indicatingcontactor switch will safely carry this current longenough to trip a circuit breaker.

The IIT and SSC-T contacts will safely close 30amperes at 250 volts dc, and will carry this currentlong enough to trip a breaker.

Three different operate level ratings for the ICS areavailable.

Trip Circuit ConstantsIndicating Contactor Switch Coil

4.0 SETTINGS

CAUTION!In order to avoid opening current transformer cir-cuits when changing taps under load, the relaymust first be removed from the case. Chassisoperating shorting switches on the case willshort the secondary of the current transformer.The taps should then be changed with the relayoutside of the case and then reinserted into thecase. Since the tap block connector screwcarries operating current, be sure that the screwis turned tight.

4.1 CO UNIT

The overcurrent unit settings can be defined either bytap setting and time dial position or by tap setting anda specific time of operation at some current multipleof the tap setting (e.g. 4 tap setting, 2 time dial posi-tion or 4 tap setting, 0.6 seconds at 6 times tap valuecurrent for the COM-7. See figure 9 page 17).

To provide selective circuit breaker operation, a mini-mum coordinating time of 0.3 seconds plus circuitbreaker time is recommended between the relaybeing set and the relays with which coordination is tobe effected.

Range Taps

0.5 – 2.52 – 64 – 12

0.5 0.6 0.8 1.0 1.5 2.0 2.52 2.5 3 3.5 4 5 64 5 6 7 8 10 12

Range:

Continuous Rating:

1 Second Rating:

Temperature Error:

Dropout Ratio:

Response Time:

Transient Overreach:

Frequency Response:

0.5 - 2 Amps2.0 - 8 Amps4.0 - 16 Amps10 - 40 Amps

Highest Current of rangesetting or 10 Amps whicheveris lower

20 Times the continuousrating

2% between -20°C and +65°C

90% to 98%

Pickup Time = (10-13) msDropout Time = (10-26) ms

For 2 to 15 times pickupsetting value, see curve 619507 (figure 23, page 30)

5% of setting

Curve No. 619505 (figure 24)

Ampere Pickup Ohms dc Resistance

0.2 8.5

1.0 0.37

2.0 0.10


6

The tap screw on the tap block above the time dial,figure 3, page 2, makes connections to various turnson the operating coil. By placing this screw in the var-ious terminal plate holes, the relay will respond tomultiples of tap value currents in accordance with thevarious typical time-current curves.

4.2 INSTANTANEOUS RECLOSING

The factory adjustment of the CO unit contact pro-vides a contact follow. Where instantaneous circuitbreaker reclosing will be initiated upon the closure ofthe CO contact, this contact follow must be elimi-nated by loosening the stationary contact mountingscrew, removing the contact plate and then replacingthe plate with the bent end resting against the con-tact spring. With this change and the contact mount-ing screw tightened, the stationary contact will restsolidly against its backstop.

4.3 INDICATING CONTACTOR SWITCH (ICS)

No setting is required on the ICS unit.

4.4 INDICATING INSTANTANEOUS TRIP (IIT)

CAUTION!Since the tap block connector screw on the IITunit carries operating current, be sure that thescrew is turned tight. To avoid opening the cur-rent circuits under load, do not change tap posi-tion without first opening all the case mountedtest switches starting with the RED handle switchfirst. Close the RED handle switch last, after alltap changes have been completed, to put therelay back into service

The proper tap must be selected (figure 4, page 3)and the core screw must be adjusted to the value ofpick-up current desired.

The nameplate data will furnish the actual currentrange that may be obtained from the IIT unit. It is rec-ommended that the IIT be set on the higher tapwhere there is a choice of tap settings. For example,for a 20 ampere setting use the 20 to 50 tap ratherthan the 6 to 20 tap.

4.5 SSC-T UNIT

The pickup setting is a screw driver adjustment madeby adjusting rheostat R2 for the desired level of cur-rent. Refer to figure 22, page 29, for the location ofR2 on the printed circuit module. A clockwise rotation

increases the trip level while a counterclockwise rota-tion decreases the tripping level.

4.6 TAPPED RESISTOR (WHEN USED)

The relay is shipped with the resistor tapped for 125volt dc service. See Figure 15 or 16, page 23 andpage 24 for the proper positions for other dc ratings.When viewed from the front of the relay the red doton terminal 1 of the resistor is next to the sub-base.

5.0 INSTALLATION

These relays have been specially designed andtested to establish their suitability for Class 1E appli-cations in accordance with the ABB Power T&DCompany program for Class 1E Qualification Testingas detailed in bulletin STR-1.

The relays should be mounted on switchboard pan-els or their equivalent in a location free from dirt,moisture, excessive vibration and heat. Mount therelay vertically by means of the four mounting holeson the flange for the semi-flush type FT case. Themounting screws may be utilized for grounding therelay. External toothed washers are provided for usein the locations shown on the outline and drilling planto facilitate making a good electrical connectionbetween the relay case, its mounting screws and therelay panel. Ground wires should be affixed to themounting screws as required for poorly grounded orinsulated panels. Other electrical connections maybe made directly to the terminals by means of screwsfor steel panel mounting.

For detail information on the FT case see figure 25.Refer to I.L. 41-076 for additional information.

6.0 ADJUSTMENTS ANDMAINTENANCE

The proper adjustments to insure correct operation ofthis relay have been made at the factory. Uponreceipt of the relay no customer adjustments, otherthan those covered under “SETTINGS” should berequired.

6.1 ACCEPTANCE CHECK

The following check is recommended to insure thatthe relay is in proper working order:

1. Contacts – For relays identified with a “T”, located at lower left of stationary contact block,


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CO Unit of Type COM-2 Relay

AMPERERANGE TAP

CONTINUOUSRATING

(AMPERES)

ONE SECOND

RATINGa

(AMPERES)

a Thermal capacities for short times other than one second may be calculated on the basis of time being inversely proportionalto the square of the current.

POWERFACTOR

ANGLEb

b Degrees current lags voltage at tap value current.

VOLT AMPERESc

c Voltages taken with high impedance type voltmeter.

ATTAP VALUECURRENT

AT 3 TIMESTAP VALUECURRENT



0.5/2.5

0.50.60.81.01.52.02.5

0.910.961.181.371.952.242.50

28282828282828

58575350403629

4.84.95.05.36.27.27.9

39.639.842.745.454.465.473.6

256270308348435580700

79085110241220174022802850

2/6

2.02.530.3.54.05.06.0

3.14.04.44.85.25.66.0

110110110110110110110

59555147454137

5.045.135.375.535.725.906.54

38.739.842.842.846.050.354.9

262280312329360420474

80092010081120121615001800

4/12

4.05.06.07.08.0

10.012.0

7.38.08.89.610.411.212.0

230230230230230230230

65504746433734

4.925.205.345.355.866.67.00

39.142.044.145.849.955.562.3

268305330364400470528

848102011281260140817202064

ENERGY REQUIREMENTSIIT Unit (60 Hz)

Rangeof IIT

TapSetting

Ohms atMinimum Pickup

Min.Pickup

Volt Amps@

5 ampsContinuous

Current1 Sec.Rating

6-144 Amps6-20 Amps

20-50 Amps50-144 Amps

0.18 ∠ 37°.026 ∠ 27°.009 ∠ 13°

62050

4.5.65.225

6 Amp13 Amp20 Amp

100 Amp230 Amp370 Amp

SSC-T Unit(60 Hz)

Range (Amps)

Pickup Current Setting

Lowest Setting Highest Setting

VA P.F. Angle Ø VA P.F. Angle Ø

0.5 - 2.02.0 - 8.04.0 - 16.0

10.0 - 40.0

0.50.50.50.8

8.5°8.5°8.5°10.0°

4.05.05.08.0

12.5°12.5°15.5°10.7°


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CO UNIT OF TYPE COM-5 AND TYPE COM-6

AMPERERANGE TAP

CONTINUOUSRATING

(AMPERES)

ONE SECOND

RATINGa

(AMPERES)

POWERFACTOR

ANGLEb

VOLT AMPERESc

ATTAP VALUECURRENT




0.5/2.5

0.50.60.81.01.52.02.5

22.22.52.83.44.04.4

56565656565656

69686766626058

3.923.963.964.074.194.304.37

20.620.721

21.423.224.926.2

103106114122147168180

270288325360462548630

2/6

2.02.530.3.54.05.06.0

88.89.710.411.212.513.7

230230230230230230230

67666463625957

3.883.873.934.094.084.204.38

2121.622.123.123.524.826.5

110118126136144162183

308342381417448540624

4/12

4.05.06.07.08.010.012.0

1618.819.320.822.52528

460460460460460460460

65636159565347

4.004.154.324.274.404.604.92

22.423.725.326.427.830.135.6

126143162183204247288

3764505316116998801056

CO UNIT OF TYPE COM-7

AMPERERANGE TAP

CONTINUOUSRATING

(AMPERES)

ONE SECOND

RATINGa

(AMPERES)

POWERFACTOR

ANGLEb

VOLT AMPERESc

ATTAP VALUECURRENT




0.5/2.5

0.50.60.81.01.52.02.5

22.22.52.83.44.04.4

56565656565656

68676664615856

3.883.933.934.004.084.244.38

20.720.921.121.622.924.825.9

103107114122148174185

278288320356459552640

2/6

2.02.530.3.54.05.06.0

88.89.710.411.212.513.7

230230230230230230230

66636362615958

4.064.074.144.344.344.404.62

21.321.822.523.423.825.227

111120129141149163183

306342366413448530624

4/12

4.05.06.07.08.010.012.0

1618.819.320.822.52528

460460460460460460460

64616058555146

4.244.304.624.694.805.205.40

22.824.225.927.329.833

37.5

129149168187211260308

3924605406266888601032


b Degrees current lags voltage at tap value current.c Voltages taken with high impedance type voltmeters.


9

CO UNIT OF TYPE COM-8 AND TYPE COM-9

AMPERERANGE TAP

CONTINUOUSRATING

(AMPERES)

ONE SECOND

RATINGa

(AMPERES)

POWERFACTOR

ANGLEb

VOLT AMPERESc

ATTAP VALUECURRENT




0.5/2.5

0.50.60.81.01.52.02.5

22.22.52.83.44.04.4

56565656565656

72716967625753

2.382.382.402.422.512.652.74

2121

21.121.222

23.524.8

132134142150170200228

350365400440530675800

2/6

2.02.530.3.54.05.06.0

88.89.710.411.212.513.7

230230230230230230230

70666462605856

2.382.402.422.482.532.642.75

2121.121.522

22.724

25.2

136142149157164180198

360395430470500580660

4/12

4.05.06.07.08.0

10.012.0

1618.819.320.822.52528

460460460460460460460

68636057544845

2.382.462.542.622.733.003.46

21.321.822.623.624.827.831.4

146158172190207248292

4204805506207008501020

CO UNIT OF TYPE COM-11 RELAY

AMPERERANGE TAP

CONTINUOUSRATING

(AMPERES)

ONE SECOND

RATINGa

(AMPERES)

POWERFACTOR

ANGLEb

VOLT AMPERESc

ATTAP VALUECURRENT




0.5/2.5

0.50.60.81.01.52.02.5

22.22.52.83.44.04.4

56565656565656

36343027221716

0.720.750.810.891.131.301.48

6.546.807.468.3010.0411.9513.95

71.875.084.093.1115.5136.3160.0

250267298330411502610

2/6

2.02.530.3.54.05.06.0

88.89.710.411.212.513.7

230230230230230230230

32302724232020

0.730.780.830.880.961.071.23

6.307.007.748.209.129.8011.34

74.078.584.089.0102.0109.0129.0

264285309340372430504

4/12

4.05.06.07.08.0

10.012.0

1618.819.320.822.52528

460460460460460460460

29252220181716

0.790.891.021.101.231.321.8

7.088.009.1810.0011.114.916.3

78.490.0101.4110.0124.8131.6180.0

296340378454480600720


b Degrees current lags voltage at tap value current.c Voltages taken with high impedance type voltmeter.


10

the index mark on the movement frame will coin-cide with the “0” mark on the time dial when the stationary contact has moved through approxi-mately one-half of its normal deflection. There-fore, with the stationary contact resting against the backstop, the index mark is offset to the right of the “0” mark by approximately.020”. The place-ment of the various time dial positions in line with the index mark will give operating times as shown on the respective time-current curves. For double trip relays, the follow on the stationary contacts should be approximately 1/32”.

2. Minimum Trip Current – Set the time dial to posi-tion 6. Using lowest tap setting, alternately applytap value current plus 3% and tap value currentminus 3%. The moving contact should leave thebackstop at tap value plus 3% and should returnto the backstop at tap value current minus 3%.

3. Time Curve – Table 1 shows the time curve cali-bration points for the various types of relays. Withthe time dial set to the indicated position and onthe lowest tap setting, apply the current specifiedby Table 1, (e.g. for the COM-2, 3 and 20 timestap value current) and measure the operatingtime of the relay. The operating times shouldequal those of Table 1 plus or minus 5%. For typeCOM-11 relay only, the 1.30 times tap valueoperating time from the number 6 time dial posi-tion is 54.9 ± 5% seconds. It is important that the1.30 times tap value current be maintained accu-rately. The maintaining of this current accuratelyis necessary because of the steepness of theslope of the time-current characteristic (figure 12,page 20). A 1% variation in the 1.30 times tap

value current (including measuring instrumentdeviation) will change the nominal operating timeby approximately 4%.

4. Indicating Instantaneous Trip Unit (IIT) – Thecore screw which is adjustable from the top of thetrip unit and the tap located on the top of the IITdetermine the pickup value. The trip unit has anominal ratio of adjustment of 1 to 24.

The indication should occur within 1/16” before,or at the same time, the contacts make.

The moving contact should provide 1/64” to 3/64”wipe of the stationary contact. This should pro-vide a minimum of 3 grms contact pressure withthe armature held against the core.

Apply sufficient current to operate the IIT. Theoperation indicator target should drop freely.

5. Indicating Contactor Switch (ICS) – Close themain relay contacts and pass sufficient dc cur-rent through the trip circuit to close the contactsof the ICS. This value of current should not begreater than the particular nameplate ratings.The operation indicator target should drop freely.

Repeat the above except pass 85% of ICSnameplate rating current. Contacts should notpick up and target should not drop.

6. SSC-T – Check to see that the SSC-T circuit canbe adjusted to trip for values of current within itsrated range. Apply the low current level of therated current range to see that the SSC-T outputrelay will operate. Reduce the current to a levelwhere the relay drops out. The drop-out currentshould be between 90% and 99% of the trip

.

PERMANENT MAGNET ADJUSTMENT ELECTROMAGNET PLUGS

RELAYTYPE

TIMEDIAL

POSITION

CURRENT(MULTIPLES

OFTAP VALUE)

OPERATINGTIME

SECONDS

CURRENT(MULTIPLES

OFTAP VALUE)

OPERATINGTIME

SECONDS

COM-2COM-5COM-6COM-7COM-8COM-9COM-11

6666666

3222222

0.5737.80

2.464.27

13.358.87

11.27

20102020202020

0.2214.30

1.191.111.110.65

0.24a

a For 50 cycle CO-11 relay 20 times operating time limits are 0.24 + 10%, - 5%.


11

value. Apply the high current value of the rangeand rotate the R2 adjustment clockwise until theoutput relay just resets, then counterclockwise sothat it just picks up. Reduce the current andcheck to see that the dropout level is between90% and 99% of the trip value. NOTE: Values oftest current greater than 10 amperes should beleft only momentarily to avoid overheating.

7. Auxiliary Time-Delay Unit (T) – For relays wiredper figure 15 or 16, (page 23 and page 24) apply100 volts dc to terminals 5 and 7. Manually closethe contacts of the telephone relay in the top left-hand corner of the relay (front view). The T unitshould operate.

6.2 ROUTINE MAINTENANCE

All relays should be inspected and checked periodi-cally to assure proper operation. Generally a visualinspection should call attention to any noticeablechanges. A minimum suggested check on the relaysystem is to close the contacts manually to assurethat the breaker trips and the target drops. Thenrelease the contacts and observe that the reset issmooth and positive.

If an additional time check is desired, pass second-ary current through the relay and check the time ofoperation. It is preferable to make this at severaltimes pick-up current at an expected operating pointfor that particular application.

Phantom loads should not be used in testing induc-tion-type relays because of the resulting distortedcurrent waveform which produces an error in timing.

All contacts should be periodically cleaned. A contactburnisher style number 182A836H01 is recom-mended for this purpose. The use of abrasive mate-rial for cleaning contacts is not recommended,because of the danger of embedding small particlesin the face of the soft silver and thus impairing thecontact.

7.0 CALIBRATION

Use the following procedure for calibrating therelay if the relay has been taken apart for repairs orthe adjustments disturbed. This procedure shouldnot be used until it is apparent that the relay is notin proper working order. (See “Acceptance Check”on p a g e6. and 11)

NOTE: A spring shield covers the reset spring of theCO Relay. To remove the spring shield, requires that

the damping magnet be removed first. The screwconnection holding the lead to the moving contactshould be removed next. The second screw holdingthe lead to the moving contact assembly should thenbe loosened but not removed.

CAUTION: This screw terminates into a nutheld captive beneath the molded block. If screwis removed, difficulty will be experienced in there-assembly of the moving contact assembly.)Slide the spring shield outward and remove fromrelay. Tighten the screw holding the moving con-tact assembly to the molded block.

7.1 CO UNIT

1. Contact – The index mark on the movement frame will coincide with the “0” mark on the time dial when the stationary contact has moved through approximately one-half of its normal deflection. Therefore, with the stationary contact resting against the backstop, the index mark is offset to the right of the “0” mark by approxi-mately .020”.

2. Minimum Trip Current – The adjustment of thespring tension in setting the minimum trip currentvalue of the relay is most conveniently made withthe damping magnet removed.

With the time dial set on “0”, wind up the spiralspring by means of the spring adjuster untilapproximately 6-3/4 convolutions show.

The spiral spring can be adjusted with the springshield in place as follows. One slot of the springadjuster will be available for a screwdriver in onewindow of the front barrier of the spring shield.By adjusting this slot until a barrier of the springshield prevents further adjustment, a second slotof the spring adjustment will appear in the win-dow on the other side of the spring shield barrier.Adjusting the second slot in a similar manner willreveal a third slot in the opposite window of thespring shield.

Set the relay on the lowest tap setting, the timedial to position 6.

Adjust the control spring tension so that the mov-ing contact will leave the backstop at tap valuecurrent +1.0% and will return to the backstop attap value current - 1.0%.

3. Time Curve Calibration – Install the permanentmagnet.

Apply the indicated current per Table 1 for per-


12

manent magnet adjustment (e.g. COM-8, 2 timestap value) and measure the operating time.Adjust the permanent magnet keeper until theoperating time corresponds to the value of Table1.

For Type COM-11 Relay only, the 1.3 times tapvalue operating time from the number 6 time dialposition is 54.9 ±5% seconds. It is important thatthe 1.30 times tap value current be maintainedaccurately. The maintaining of this current accu-rately is necessary because of the steepness ofthe slope of the time-current characteristic (figure12, page 20). A 1% variation in the 1.30 times tapvalue current (including measuring instrumentdeviation) will change the nominal operating timeby approximately 4%. If the operating time at 1.3times tap value is not within these limits, a minoradjustment of the control spring will give the cor-rect operating time without any undue effect onthe minimum pick-up of the relay. This check is tobe made after the 2 times tap value adjustmenthas been completed.

Apply the indicated current per Table 1 for theelectromagnet plug adjustment (e.g. COM-8, 20times tap value) and measure the operating time.Adjust the proper plug until the operating timecorresponds to the value in Table 1. (Withdrawingthe left-hand plug, front view, increases the oper-ating time and withdrawing the right-hand plug,front view, decreases the time.) In adjusting theplugs, one plug should be screwed in completelyand the other plug run in or out until the properoperating time has been obtained.

Recheck the permanent magnet adjustment. Ifthe operating time for this calibration point haschanged, readjust the permanent magnet andthen recheck the electromagnet plug adjustment.

4. Indicating Contactor Switch (ICS) – Use the fol-lowing procedure for calibrating the relay if therelay has been taken apart for repairs or theadjustments have been disturbed. This proce-dure should not be used unless it is apparent thatthe relay is not in proper working order. (See“Acceptance Check” on page 6. and 11.)

Initially adjust unit on the pedestal so that arma-ture fingers do not touch the yoke in the resetposition. This can be done by loosening themounting screw in the molded pedestal and mov-ing the ICS in the downward position.

a) Contact Wipe: Adjust the stationary contactsso that both stationary contacts make with

the moving contacts simultaneously andwipe 1/64” to 3/64” when the armature isagainst the core.

For double trip type units, adjust the thirdcontact so that it makes with its stationarycontacts at the same time as the two maincontacts or up to 1/64” ahead.

b) Target: Manually raise the moving contactsand check to see that the target drops at thesame time the contacts make or up to 1/16”ahead. The cover may be removed and thetab holding the target reformed slightly if nec-essary. However, care should be exercisedso that the target will not drop due to a slightjar.

c) Pickup: Unit should pickup at 98% of ratingand not pickup at 85% of rating. If necessarythe cover leaf springs may be adjusted. Tolower the pickup current, use a tweezer orsimilar tool and squeeze each leaf springapproximately equally by applying the twee-zer between the leaf spring and the front sur-face of the cover at the bottom of the lowerwindow.

If the pickup is low the front cover must beremoved and the leaf springs bent outwardequally.

5. Indicating Instantaneous Trip Unit (IIT) –Use thefollowing procedure for calibrating the relay if therelay has been taken apart for repairs or theadjustments disturbed. This procedure shouldnot be used until it is apparent that the relay isnot in proper working order. (See “AcceptanceCheck” on page 6. and 11).

Initially adjust unit on the pedestal so that thearmature fingers do not touch the yoke in thereset position. This can be done by loosening themounting screw in the molded pedestal and mov-ing the IIT in the downward direction.

a) Contact Wipe: Adjust the stationary contactsso that both stationary contacts make withthe moving contacts simultaneously andwipe 1/64” to 3/64” when the armature isheld against the core. This can be accom-plished by inserting a .0125 thickness gaugebetween the armature and core and adjust-ing the stationary contacts until they justtouch the moving contacts.


13

For double trip types adjust the third contactuntil it makes with its stationary contact atthe same time as the two main contacts orup to 1/64” ahead.

b) Target: Manually raise the moving contactsand check to see that the target drops at thesame time the contacts make or up to 1/16”ahead. If necessary, the cover may beremoved and the tab holding the targetreformed slightly. However, care should beexercised so that the target will not drop dueto a slight jar.

c) Pickup: Place tap screw in the 6 to 20 tapand turn the core screw all the way in. Con-tacts should pickup between 5.1 and 5.7amperes. If pickup is above this range it maybe reduced by using a tweezer or similar tooland squeezing each leaf spring approxi-mately equally by applying the tweezerbetween the leaf spring and the front surfaceof the cover at the bottom of the lower win-dow. If the pickup is below this range it maybe increased by removing the front cover andbending the leaf springs outward equally. Anapproximate adjustment would be where theend of the leaf spring is in line with the edgeof the molded cover.

The desired pickup is obtained by setting thetap screw in the proper range and adjustingthe core screw.

6. High Drop-out Instantaneous Unit (SSC-T) –Check to see that the SSC-T circuit can beadjusted to trip for values of current within itsrated range. Apply the low current level of therated current range to see that the SSC-T outputrelay will operate. Reduce the current to a levelwhere the relay drops out. The drop-out currentshould be between 90% and 99% of the tripvalue. Apply the high current value of the rangeand rotate the R2 adjustment clockwise until theoutput relay just resets, then counterclockwise sothat it just picks up. Reduce the current andcheck to see that the dropout level is between90% and 99% of the trip value. NOTE: Values oftest current greater than 10 amperes should beleft on only momentarily to avoid overheating.

8.0 RENEWAL PARTS

Repair work can be done most satisfactorily at thefactory. However, interchangeable parts can be fur-nished to the customers who are equipped for doingrepair work. When ordering parts, always give thecomplete nameplate data.

9.0 OBSOLETE UNIT INFORMATION

9.1 IITH

Any information needed as to the characteristics, set-tings, adjustments, maintenance, calibration, or energyrequirements may be found in L-Spec L-914526.


14

Figure 6 :Typical time curves of the type COM-2 relay.

Sub 1Curve 619509


15


Curve 619510

Sub 1


16

Figure 8: Typical time curves of the type COM-6 relay.

Curve 519511

Sub 1


17


Curve 619512

Sub 2


18

Figure 1 0 :Typical time curves of the type COM-8 relay.

Curve 619513

Sub 1


19


Curve 619514

Sub 1


20


Curve 619515

Sub 1


21

Figure 13: External schematic of COM relays without auxiliary time-delay unit and SSC-T unit.

Sub 11616C27

Sub 11616C27


22

Fig

ure

14:

Ext

erna

l sch

emat

ic o

f CO

M r

elay

s w

ith a

uxili

ary

time-

dela

y un

it an

d S

SC

-T u

nit.

Sub

115

05B

40


23

LOW SET

LOW SET

Figure 15: Internal schematic of type COM-5 relay with auxiliary time-delay unit and SSC-T unit in FT-21 case.

Sub 63518A47


24

Figure 16 :Internal schematic of type COM-9 with auxiliary time delay unit and SSC-T unit in FT-21 case.

Sub 23532A61


25

Figure 1 7 :Internal schematic of type COM-5 relay with SSC-T unit and without auxiliary time-delay unit in FT-21 case.

Sub 13531A05

LOW SET

LOW SET


26

Figure 1 8 : Internal schematic of type COM-5 with SSC-T unit and IIT Contacts out to separate terminals in Type FT-21 case.

Sub 13531A07


27

Figure 1 9 :Setting example of motor protection without auxiliary time-delay unit.

Sub 19663A38


28

Figure 2 0 :Setting example for motor protection with auxiliary time-delay unit.

Sub 19663A39


29

Fig

ure

21:

SS

C-T

mod

ule

inte

rnal

sch

emat

ic fo

r C

OM

-5 C

lass

1E

.

Fig

ure

22:

SS

C-T

mod

ule.

Sub

235

18A

43

Sub

277

5B80

1


30

Figure 23: Time Curve for SSC-T Unit.

Sub 1619507


31

Fig

ure

24:

Freq

uenc

y re

spon

se fo

r S

SC

-T u

nit.

Su

b 1

6195

05

41-102.1b com overcurrent relay · 2018-05-10 · 41-102.1b com overcurrent relay 6 the tap screw...

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