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7.6KW BT· GENERATOR TROUBLESHOOTING
This troubleshooting chart is designed to give insight into
problems which may be encountered with BT brushless
generators operating on compound transformer regulation.
Owing to the simplicity of the equipment and controls,
troubleshooting is relatively easy, once the relationship
between cause and effect is understood.
WESTERBEKE recommends that the troubleshooting and
repair of .the generator be performed by a qualified technician
with a thorough knowledge of electricity and the safety
procedures necessary when dealing with high voltages.
Problem
Probable Cause
Only a few basic tools are necessary for diagnosis and repair.
These are hand tools: an amp probe and a quality volt-ohm-
meter capable of reading less than one ohm due to the
precision required in reading component winding resistances.
Before attempting any repairs, get a clear an explanation of
the problem as possible, preferably from an individual
witnessing the problem. In some cases, this may bring to
light a problem which is related to the method of operation
rather than equipment fault. Have basic repair parts available,
such as: diodes and a bridge rectifier, so that if the problem is
found in one of these easily replaceable parts, repairs can be
made efficiently.
VerificationJRemedy
High voltage (125 -135 volts) at NIL with
1. Generator's engine speed (rpm) high at NIL. 1. Check NIL speed and adjust NIL voltage.
correct voltage when loaded
(115 -120 volts).
High voltage at NIL and F/L.
1. Generator's engine speed (rpm) high.
1. Check NIL rpm and adjust NIL voltage.
2. Short in compound transformer auxiliary
2. Check continuity and connections of 0-3 windings.
windings 0-3.
Low voltage (0 - 5 volts) at NIL with
1. Main stator windings shorted C-1, C-2.
1. Check continuity and resistance values of C-1, C-2 windings
growling noise from generator and loss of
and connections.
engine speed when load is applied.
2. Compound transformer windings shorted
2. Check continuity and resistance values of 0-1, 0-2 windings.
0-1,0-2.
Generator does not excite; voltage is
1. Generator's engine speed is slow.
1. Adjust the engine's speed and adjust NIL voltage.
is 0 volts at NIL.
2. Short in the main stator windings or
2. Check the diodes as shown in this manual.
transformer.
3. Shorted Posi-resistor.
3. Test Posi-resistor.
Low voltage (60 - 100 volts) at NIL, when
1. Oiodes(s) in rotating exciter (B-2) shorted.
1. Check B-1 and B-2 in the rotating exciter as explained in
load is applied, voltage drops.
this section.
2. Rotating field windings.
2. Check for short.
3. Exciter rotor windings.
3. Check for short a, b, c.
4. Exciter stator windings.
4. Check for short.
Voltage correct at NIL, but not at FIL with
1. Generator overload.
1. Monitor the load.
loss of engine rpm (hertz).
2. Rotating diode failing.
2. Check the diode.
3. Generator's engine speed is low.
3. Check the governor operation.
4. Low power load factor.
4. Check the type of load applied. Consider use of optional
regulator board.
Unstable voltage.
1. Engine's rpm fluctuating.
1. Check the engine operation and the fuel system.
See ENGINE ADJUSTMENTS.
Residual Voltage (18 - 22 volts)
1. Bridge rectifier.
1. Test rectifier.
2. Exciter stator.
2. Test winding for open.
3. Transformer windings.
3. Test winding for open.
4. Main stator sux. windings.
4. Test winding for open.
Engines & Generators
38
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Troubleshooting
