alternator problems
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April 2001 Aircraft Maintenance Technology www.AMTonline.com
If you've ever had an out-of-box failure of a replacement alternatorthen you need no description of the frustration you felt when that hap-pened. If you havent had that experience then no description will do itjustice. Technical Reps and Warranty Administrators develop this same
sense of frustration when a returned out-of-box failure unit tests to spec-
ifications.
Aircraft charging systems occasionally present a real troubleshootingchallenge. As Tech Service Reps, we would like to minimize your frustra-
tion and ours by offering the following insights for solving commonly
encountered problems. Given the complexity of the charging system, the
information presented in this article will be necessarily brief. We will focus on
the high spots of alternator troubleshooting. Other related components
and some of their effects will also be addressed.
Throughout the years, weve received numerous calls requesting tech-
nical assistance with charging system problems. About the time we think
we have heard it all something new comes along. The old adage that
You can never know it all certainly applies to alternators! The only
consistent factor is that two basic scenarios exist. The first scenario is
It was working OK and now it isnt, and the second scenario is I just
installed it and it doesnt work. This second scenario can be muchmore insidious and difficult to troubleshoot, especially if you are
uncertain as to the failure mode that caused you to change the
component in the first place.
At a risk of pointing out the obvious, your first step should always
be to verify that the alternator was correctly installed. Is everything
properly routed and secure? With belt-driven units, is the belt tension
proper? These questions and others equally apply to units that fail soon
after installation.
If all else fails, read the directionsManufacturers frequently include installation instructions and some even
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1
By Winston Greer & Mike McC luskey of Kelly Aerospace Powe r Systems.
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February 2001Aircraft Maintenance Technology www.AMTonline.com2
include a test report packaged with the unit. Occasionally,
parts dispatchers remove this information so as to include
them in the customers file. Sometimes these papers actually
end up being discarded with the thought of helping the
mechanic by removing extraneous tags, etc. If you deal with a
dispatcher in your organization, ask if you can look over any
information that came with the unit. If a manufacturers bench
test report shows that the unit came off their production lineoperating properly, then its not likely any fault lies with the
replacement unit. If you are the one who actually opened the
box and you are sure there are no directions or test reports
included, look for other contact information such as the man-
ufacturers telephone or fax number on the box or data plate,
even a web site or email address. In many cases, the manufac-
turer has a toll-free number to call for technical assistance.
Spend a few moments reviewing installation instructions
and performance criteria (see Figure 1). This exercise may pre-
vent you from removing a good replacement unit and
installing yet another potentially misdiagnosed out-of-box
failure. Confirming how the installation is to be performed
correctly,either through written instructions or with coachingby a Technical Service Representative, can likely save you that
out-of-box failureexperience and get your customer back in
the air sooner.
Systemsimilarities & differencesThere are three basic types of alternators used on general
aviation aircraft: the Ford style, the Chrysler style, and the
Prestolite style. The basic principle remains the same for all
three models: the alternators job is to produce AC and con-
vert it to direct electrical current before leaving the device. In
so doing, the alternator provides the direct current required by
the aircraft instrumentation and equipment.
Distinctions between these models are minor. The great-
est difference lies in the wiring configuration of the voltage
regulator and the alternator. In some installations, the current-
controlling element of the voltage regulator is in series
between the A/C bus (direct current) and the alternator field
(F1). Only one field terminal will appear on the back of the
alternator, with another being internally grounded.
Alternators with single-lead brush racks will always be wired in
this manner. In other installations, the current-controlling ele-
ment is located between the alternator field (F2) and ground.
In these installations, the alternator will have two field termi-
nal connections available. Alternators with two-lead brushracks can be wired either way.
Grounding of field terminalsOne common technical assistance request is diagnosing a
newly installed alternator that doesnt work. Most Prestolite-
style alternators have two field terminals: one must be
grounded directly or through the regulator. Some airframe
manufacturers install a very small metal tab going from the F2
terminal to the brush holder screw. Better look close, though;
given a well-used alternator, if you dont know its there, youll
never see it (see Figure 2).
Identifying the failure mode/isolating the causeNow back to the first scenario: The alternator was work-
ing OK and now it isnt.Presuming that an alternator bearing
failure is not involved, that connections all check OK, and cor-
rect belt tension has been confirmed for those belt-driven
Its w ell know n that charging system components can affect radio com-
munication in the form of noise. Failing diodes or a bad stator w ill normal-
ly generate a whine i n the headset that w ill vary in pitch w ith the R.P.M . of
the engine. Radio noise falsely attri buted to leaking diodes or a partial shortin the stator can be one of t he hardest problems to track down and solve.
Given a new manifestation of radio noise, one of the easier checks is for
alternator wires situated too close to the antenna cables. Alternators inher-
ently make some electrical noise and if w iring has recently been re-routed
too close to antenna cables, the radio will pick it up. If you have shielded
w iring going to or from t he alternator, make sure both ends of the shield are
properly grounded and that you have good continuity to the airframe. Its
also advisable to inspect the connections at the batt ery. These connections
should be perfectly clean, bright and tight. Often overlooked is the connec-
tion of the ground strap from the engine to the engine mount. These con-
nections tend to corrode over time and you cannot see t he corrosion w ith-
out taking the ground strap off. If both ends of the connection are clean and
tight and the problem persists, then unfortunately everything else has to be
checked. Be certain to look closely before deciding all is OK; the problem of
corrosion can be very subtle. It only takes about 0.2 ohms resistance on theground plane to cause radio noise (and a variety of ot her problems). A friend
had an older airplane wit h the battery mounted in the rear. He had radio
noise, slow cranking R.P.M ., apparent alternat or problems, and several other
electrical problems. It was recommended that he run a dedicated ground
w ire from the battery to the firew all. W hen he did, all his electrical prob-
lems w ent aw ay. Over the years, the aluminum skin of the aircraft had oxi-
dized w here it w as overlapped and riveted, putting too much resistance in
his ground plane. Regrettably, all solutions are not this simple. Once all
potential sources of radio noise have been investigated and eliminated, you
may have a genuine avionics problem. Your local avionics shop wil l have to
be consulted for further investigation and diagnosis.
Radio Noise
Figure 1:Technical
documenta-tion a valu-able source ofinstruction,product per-formancedata, and
manufactur-ers contact
information.
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units, then use your
multimeter to check and
see if there is resistance on
the alternator field. If the field is
open, then the culprit is a bad rotor or brushes. If the
field checks OK (generally 3 to 25 ohms), the next step
would be to make sure voltage is getting to the field. If
not, then its the regulator or the wiring. Determine
whether or not voltage is getting to the regulator; if so,
then the regulator most probably is the culprit. If every-thing is checking as it should, by default, things continue
pointing to the alternator as the source of the trouble.
There is one more test to make before you remove it from
the engine use an analog ohmmeter to check the
resistance between the output terminal and ground (a
digital ohmmeter wont work). This is a reverse polarity
test so you have to ground the positive probe and contact
the negative probe on the terminal. The reading should
be between 30 and 50 ohms; a lower reading than this
indicates the stator or diodes are gone, and the alternator
must be repaired or replaced.
Low current outputThe next most common variant of the It was work-
ing OKscenario is low current output (this can cause a
technician to consider changing careers!). As with most
other problems, there can be several reasons for the
manifestation of low current output the most frequent
one being a shorted or burned stator.
A failed diode is the next most-common suspect
immediately following a suspected stator. With a failed
diode, you will likely experience radio noise. Modern
diodes are much more reliable and durable than those
used even just ten years ago, having a much higher
mean-time-to-failure life expectancy. Core unitsreturned to our shop have had the stator shorted and
burned with fully functional diodes; however, this is the
exception instead of the rule. The point is that diodes
today can handle the stress of stator failure better than
ever. Still, its not advisable to reuse diodes that have sur-
vived a stator failure due to induced stress, coupled with
a high probability of damage and subsequent loss of
durability.
Another possible cause of low current output is a
partially shorted rotor. In this case, the wires in the rotor
coil short to each other but not to ground. This lowers the
resistance of the coil, thus lowering the magnetic flux of
the rotor and the output of the alternator.
Brushes are yet another culprit that can certainly
contribute to low current output. Be certain to inspect
the brushes. Are they worn? Are they making positive
contact with the slip ring on the rotor? Most alternator
manuals give minimum lengths for brushes. If you hap-
pen to disassemble an alternator for any reason and itsbeen in service for a while, always measure the brushes.
For gear-driven alternators, the last and certainly
ugliest suspect for low output is the one that your cus-
tomer really doesn't want to hear about: The coupling
gear is slipping. As you may already know, the reason
your customer doesnt want to hear about this is that in
many cases, the replacement cost of a coupling gear is
two or three times the replacement cost of an alternator.
Coupling gears have rubber inserts that act as a torsion-
al buffer; the inserts are designed to shear to prevent
damage to the engine in case the alternator stops sud-
denly (for example, if something gets inside the alterna-
tor and locks it up). The rubber material of the inserttends to harden with age and heat and will eventually
allow the two halves of the gear to slip. A good indication
that the coupling gear is responsible for low alternator
output is when the system works fine with light electrical
loads but the amperage and/or the voltage starts drop-
ping as you add additional load. Engine manufacturers
service bulletins explain how to test coupling gears for
minimum slip torque. Also, if you are experiencing high
voltage with low output, this can be caused by leaky
switches and circuit breakers. If these components have
never been replaced, then now is the time to consider
doing so.
Pulsing ammeterAnother first scenario common complaint is an
oscillating or pulsing ammeter needle. Like all other
troubleshooting problems, knowing where to start look-
ing for solutions will conserve your time and temper.
Usually this problem is caused either by the field circuit
breaker, the alternator switch, or both. However, the reg-
ulator over voltage sensor might also be bad. To diagnose
the problem, turn the electrical system on without start-
ing the engine and measure the voltage coming off the
output terminal of the alternator. Next, measure the volt-
age on the input (power) wire of the regulator and com-pare the two readings. If there is
more than one-half (0.5) volt dif-
ference between these read-
ings, then, as you recall from
our earlier comments, either
(1) the circuit breaker is
Figure 2:Example of a
ground strap onthe field for a
Prestolite-stylealternator. These
can be easy tooverlook, per-
haps the reason a
mechanic hadmarked this one.
Figure 3: Just as overworn brakepads grind brake rotors, brushes
that have gone too long and beenworn too far cause irreparable
harm to mating slip rings.
www.AMTonline.comAircraft Maintenance Technology February 2001 3
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February 2001Aircraft Maintenance Technology www.AMTonline.com4
defective; (2) the alternator switch is
defective; or (3) the over voltage sensor
is bad. Note:You could have any combi-
nation of the three.At this point, check
the input voltage of the circuit breaker
and compare it with the output voltage.
Again, if there is more than one-half
volt difference, the circuit breaker mustbe replaced. Then perform the same
input-voltage versus output-voltage
test on the alternator switch. There
cannot be more than one-half volt dif-
ference or the switch must be replaced.
Voltage differences inside the switch or
circuit breaker originate at the con-
tacts. When they lose the dielectric
grease they are packed with, they arc
and pit and oxidize on the contact sur-
face. These compromised surfaces
eventually lose the ability to properly
conduct current. The outcome is very
much like magneto breaker points that
have been run a long time. Although it
is rare, one last possible cause of an
oscillating or pulsing ammeter is the
regulator itself. There are some early
regulator designs that operate on sucha low frequency that they will cause the
ammeter needle to pulse at low RPM
with a moderate load. If you have one
of these regulators you have two choic-
es: (1) live with it; or (2) upgrade to a
newer, high frequency regulator.
Nuisance trippingThe final problem well discuss
could fall in either of our two scenarios:
an alternator that drops off line for no
apparent reason. A simple cycling of
the alternator switch temporarily cor-
rects the problem. For obvious reasons,
this is frequently referred to as nui-
sance tripping. The first thing to
check for is a poor connec-
tion in the remote sense or
field wires. Some regula-tors are very sensitive
to ambient electrical
noise and any inter-
mittent condition will
cause the system to trip
off line. If connections
are confirmed as good
and the problem persists, then look at
the alternator itself. Even the slightest
scratch on the slip ring of the rotor can
cause nuisance tripping. Inspect the
brushes for excessive wear; especially
note if the copper wire is showing, andif it is then the brushes must be
replaced (see Figure 3). When the
brushes are too short, the brush spring
may no longer maintain proper pres-
sure for brushes-to-slip ring contact.
Before reassembly, the alternator slip
ring must be resurfaced. Dont ruin
your good work on the slip ring (see
Figure 4); use a piece of plastic or plas-
tic-insulated wire (you can even use a
toothpick) as a brush retainer in the
brush block (see Figure 5). Bare metal
wire can scratch the slip ring when its
pulled out of the brush block to release
the brushes once reassembly is com-
plete. It doesnt take very much arcing
between the brushes and the slip ring
to trip some systems off line and even a
tiny scratch can initiate or perpetuatethe dropping off line problem. If
youve looked at the alternator and are
confident that its not the source of the
problem, it is very probable that the
regulator overvoltage circuit or sepa-
rate overvoltage sensor is failing. Some
systems have no overvoltage protec-
tion at all, some have regulators with
overvoltage protection built in, and
others have a separate overvoltage sen-
sor. Make sure you know which you
have before replacing them.
This has been a very basic survey
of single engine electrical system trou-
bleshooting. Just remember one thing:
if you cant figure out whats wrong
dont hesitate to call a manufacturers
Technical Service Representative.
They probably can save your time
and frustration, your
customers money and
both you and your cus-
tomer a few gray hairs!
A M T
Figure 5: Insulated wire used as the brushretainer prior to re-installation of the
brush block. Bare wire can scratch the slipring when removed to release the brushes
Figure 6: One manufacturers technicalservice contact information.
Winston Greer is VicePresident of Qualityand Mike McCluskeyis a Technical Service
Representative forKelly Aerospace Power
Systems in FortDeposit, AL.
Figure 4: How your slip ring shouldlook when you are ready to reinstall the
rotor.
Reprinted with permission from
Aircraft Maintenance Technology, April
2001
KA40301
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September 2001 Aircraft Maintenance Technology www.AMTonline.com
Multi-engine alternator charging system troubleshooting
By Winston Greer and Mike McCluskey
M
ulti-engine electrical systems are nothing
more than single-engine systems coupled
together to make them work as a unit.
Continuing the treatment of alternator troubleshoot-ing from our initial article on this subject in the April
2001 issue of AMT, for this installment we will be dis-
cussing twin-engine applications.
If you are an optimist, then you might consider
twins an opportunity for:
1. Performance improvement
2. Increased safety through engine redundancy
3. Revenue-enhancement of your operation
If you are a pessimist, then you might think of
twins as just a way of doubling your problems.
Somewhere between these two extremes lies reality.
With more knowledge about troubleshooting twin-engine charging systems, you are more likely to adopt
a more optimistic perspective.
Basic theoryLets review the basics. An alternator is an electro-
mechanical device that converts mechanical energy to
electrical energy. A regulator is an elec-
tronic device that controls both the volt-
age and the field current of an alternator.
Fundamentally, all of this sounds quitesimple and it is, but interesting out-
comes can occur if everything is not
just right.Many of the topics covered
in this article are expansions on the
fundamentals discussed in the April
2001 installment, Taking Charge of
Alternator Problems. The funda-
mentals of troubleshooting single-
engine charging systems are the
same as those for troubleshooting
multi-engine applications.
However, significantdifferences do exist
between single
and multi-
engine appli-
cations. This
expanded
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www.AMTonline.comAircraft Maintenance TechnologySeptember 2001
treatment of the subject should
help to resolve some of the more
perplexing problems associated
with multi-engine alternator sys-
tems.
High Frequency RegulatorsRecently, the major reason forchanging regulator equipment is
to upgrade to newer designs that
operate at a higher frequency than
earlier designs. Higher frequency
(faster) regulators tend to elimi-
nate the wagging needle on
ammeters that earlier-designed
regulators were prone to cause.
These older regulators generally
operate at a frequency close to the
alternator frequency. As a result,the regulator tries to follow the
alternator and vice versa, causing
the pulsing or wagging of the
ammeter indicator. Another major
reason for changing to newer-
design regulator equipment is the
advantage of built-in ground-fault
protection. From a cost-to-benefit
ratio standpoint, this is one of the
great newer developments in regu-
lator design. With earlier-designed
regulators, a short in the alternatorfield would blow the regulator.
With ground-fault protected regu-
lators, the regulator is not dam-
aged, and an LED comes on to
alert of the ground-fault condition.
This is also a great diagnostic tool.
If an alternator keeps dropping off-
line and the LED comes on, then
you know the failure mode is the
field circuit. This feature saves a lot
of time (and money) when a
ground-fault problem occurs.Some technicians keep this type of
regulator in their toolbox and uti-
lize it as a diagnostic instrument
when the airplane they are work-
ing on doesnt have the newer-
design type of regulator.
ParallelingParalleling remains the most
challenging aspects of installing
alternators or regulators in twin-
engine applications, and it is herewhere those interesting out-
comesmight first become appar-
ent. An airframe manual will, in
most cases, give you instructions
on the proper procedures to follow.
Electrosystems Paralleling Proced-
ure Service Instruction SI-0101 may
also prove helpful, especially if the
aircraft electrical system has been
upgraded.
One circumstance that occurs
with increasing regularity is theinstallation of regulators that are
not original equipment for that
particular aircraft. In this case, the
manufacturer would have includ-
ed regulator-specific paralleling
instructions and may differ from
the original equipment regulator
paralleling instructions outlined in
the aircraft manual. These instruc-
tions are specific to the initial
installation, and may differ from
those supplied by a different regu-lator manufacturer.
In most cases, when upgrad-
ing to the new, high frequency reg-
ulators, they must be replaced in
pairs to allow for the units to talk
to each other. If you replace the old
style Linear regulator with the new
style high frequency switching reg-
ulator the units wont talk to each
other and paralleling the system
will be virtually impossible.
SystemoutputimbalanceAlthough single-engine trou-
bleshooting tips apply easily to
multi-engine applications, multi-
engine systems can present a host
of unique challenges. Always
remember to start with the obvi-
ous solutions: make certain that
the alternators on both engines are
properly installed, the wiring is
properly connected and routed,
the belt-tension is appropriate forbelt-driven units, the battery is
adequately charged, etc. However,
many pilots and mechanics think
that after paralleling is complete,
both alternators should produce
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ALU-8521L ALT.
ALU-8521R ALT.
F2F1
+
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+
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MIN.
BUS
BUS
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GND GND
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PARALLELINGPAR
VR286 (28V) VR286 (28V)
AIRCRAFT BUS
24-VOLT FIELD PARALLELING SYSTEM
OS75-28(over voltage
sensor)
OS75-28(over voltage
sensor)
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exactly the same amount of cur-
rent on each side. This is not usual-
ly true. As much as 10 amperes dif-
ference may be normal. Many vari-
ables such as the wiring, the regu-
lators, the ground system and the
alternators themselves may con-
tribute to the imbalance between
the two sides. If the difference is
less than 15 percent (e.g., about 10amps for 70-amp alternators),
then searching for the cause may
require more time than you can
spare, in order to achieve very lit-
tle, if any, improvement.
Air gap differentialsIf imbalance in the two alter-
nators exceeds about 15 percent,
then improvement should be pos-
sible. Certainly, no two alternators
perform exactly alike this isespecially true in overhauled
units. Most of the components in
an overhauled unit have been
used at least once. These compo-
nents will, in most cases, have
wear differentials that contribute
to output imbalance. A good
example is the air gap between the
rotor and the stator, which may
cause a considerable difference in
the current output. All else being
equal, if one alternator has a0.010-inch air gap, and a second
has a 0.005-inch air gap, there will
be a noticeable difference in the
output, especially at low RPMs.
While the physics are not neces-
sarily intuitive, the effects of the
difference in the magnetic flux
producing the current vary expo-
nentially with distance. Simply
stated, doubling a difference in the
air gap of two alternators will
result in a rate of change greaterthan double that value. Just
remember that small differences
in air gaps can have a large effect
on output differences. When the
installation, or more likely the
customer requires a closely bal-
anced system the best option
may be to install new units
instead of overhauled ones. Eventhen, they will not likely produce
exactly the same output, though
the difference should go unno-
ticed.
Drive gears and beltsIn the case of gear-driven
alternators, serious imbalance
may be caused by the coupling
gears. If one coupling gear is slip-
ping, then the alternator may not
turn fast enough to produce thesame amount of current. There
are service bulletins addressing
this problem with detailed
instructions on how to properly
test the coupling gears. It is a
good idea to test the coupling
gear any time the alternator is
changed. These gears have rub-
ber inserts that tend to become
hard and brittle with age and
heat. Unfortunately, in most
cases the coupling gear costsmuch more than the alternator,
so be absolutely sure that it is
defective before you purchase a
new one. On belt-driven alterna-
tors, proper belt tension is very
important. Engine and alternator
manufacturers publish service
instructions on the proper ten-
sioning of the drive belts. To
ensure performance and reliabili-
ty, these service instructions
should be followed closely. If thealternator belt is too loose, it may
slip, and the alternator will not
turn at the speed necessary to pro-
duce the required output under
load. If the belt is too tight, it may
cause bearing failure.
Wiring, Terminals, andConnectors
As previously mentioned,
another unique challenge is prop-
erly maintaining the electrical sys-tem wiring. It doesnt require high-
er math to recognize that there
September 2001Aircraft Maintenance Technologywww.AMTonline.com14
If you have an aircraft that uses gen-
erators, then you might want to consider
converting to alternators with aSupplemental Type Certificate (STC). Since
most general aviation generators have not
been manufactured in over 30 years,
approved generator parts are getting hard-
er and harder find. In most cases, alterna-
tors weigh less than generators, and are
more reliable. Furthermore, in some cases,
it costs less to convert to alternat ors than to
have the generators overhauled.
When considering the conversion
from a generator system to an alternator
system, the first t hing to determine is w hatSTCs are available for your aircraft. One
good place to start looking is the FAA w eb-
site http://av-info.faa.gov/stc/ w here you
may search using many different parame-
ters.
STCs come in every conceivable form,
from paperwork-only where you obtain
the parts yourself and make the w iring har-
ness, to companies that provide the STC
and perform the installation. STC installa-
tions at the STC-holders facility are gener-
ally very good, and even more attractive if
you are close to one of their facilities and
convenience is the greater consideration.
But, getting an STC kit seems to bethe most popular option. There are many
compelling reasons for this popularity. A
good STC kit has everything needed for the
conversion including instructions, parts,
and required FAA paperwork; all you have
to provide for your customer is the installa-
tion labor. STC-holder installations may be
too expensive or located too far aw ay to be
convenient. With a paperwork-only STC,
you have to find the parts: alternators, cir-
cuit breakers, switches, wire, brackets, pul-
leys, etc. Then you must make the harness,and perform the installation. It is not a good
idea to merely add the extra w ires required
for the conversion; the old wires probably
have insulation that is hard and cracking
and could cause new problems in a rela-
tively short period of time. In fact, old w iring
alone in some cases might be j ustification
enough to perform a conversion.
No matter which option you choose,
you can know that your electrical system is
up-to-date, with parts and service more
readily available.
Generator to A lternator C onversions
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may be at least twice as much electrical wiring in a
twin-engine system as there is for a single-engine sys-
tem. This means, of course, that there are more areas
where insulation can become chafed, and more poten-
tial for connectors to loosen and/or corrode. Make
sure that the terminal ends are clean and tight and that
there are no broken wires or wiring with chafed insula-tion. Good luck this can often be like finding the
proverbial needle in the haystack.
Ground systemproblemsAs we noted in the April 2001 AMTRadio Noise
sidebar, the ground system can present some of the
most serious troubleshooting challenges. Many techni-
cians change alternators, regulators, wiring and other
charging system components only to find that the air-
craft has a bad ground system. If you have more than
0.2 ohms resistance in the ground system from either
of the alternators to battery ground, it is time to startcleaning connections. Recall that other usual sus-
pectsof a bad ground can be the field circuit breakers
or alternator switches. To troubleshoot this, measure
the voltage at the bus bar with the system turned on
and the engines not running, then check the voltage
going into the regulator. If any breaker or switch has
more than a 1/2-volt difference from the input side to
the output side, then it is probably defective, and
should be replaced. To determine which one, you will
have to go directly to the switches or circuit breakers.
Anomalies associated with temperaturevariationsAnother consideration in setting up the alterna-
tors is temperature.
Alternator current is
inversely proportional to
temperature; that is, output
decreases as alternator
temperature increases. You
might have two alternatorsperfectly paralleled when
cold, but after they warm
up they become unaccept-
ably out of balance. Have
the pilot verify the balance
on the first flight after an
alternator is replaced or
reinstalled; you may have to
adjust the system when the
plane returns.
Some regulator models
are also more heat-sensitivethan others. The installa-
tion location of the regula-
tors might also increase (or
decrease) this effect. Some
regulators even require a
heat sink to dissipate the heat that they generate, so
(once again pointing out the obvious) be sure to read
the manufacturers' instructions. If you dont have suf-
ficient information, dont hesitate to call the manufac-
turer for technical assistance.
When aircraft charging systems go wrong, it can
be tempting to look at the situation from the bad sideand get frustrated. But bad perspectives can result in
bad outcomes. Hopefully these articles on charging
system troubleshooting have provided information
that can help keep your perspective optimistic. Here's
to your successful outcomes. A M T
Winston Greer is Vice President of Quality and MikeMcCluskey is a Technical Service Representative forKelly Aerospace Power Systems in Fort Deposit, AL.
Recip Technology
www.AMTonline.comAircraft Maintenance TechnologySeptember 2001 15
Paralleling remains the most challenging aspects of installing alternators or regulatorsin twin-engine applications.
Ke
lly
Aerospace
Power
Sys
tems
2001
Additional resources....
Kelly Aerospace Power Systems Product Support(888)-461-6077
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