GENERATOR BUILDS VOLTAGE FROM STARTUP,
THEN GOES TO LOW (RESIDUAL) VOLTAGE
CAUSE CHECK AND REMEDY
Regulator protective circuit operating Check indicators on regulator. Correct problems and adjust regulator as is required.
Refer to regulator manual.
GENERATOR IS OVERHEATING
CAUSE CHECK AND REMEDY
Generator is overloaded Reduce load. Check with ammeter and compare with nameplate rating.
Clogged ventilating screens Clean air passages.
High room temperature or altitude Improve ventilation or reduce load.
Insufficient circulation of cooling air Generator location and enclosure design must provide adequate air flow and
minimize recirculation of hot air.
Unbalanced load The load on each leg should be as evenly balanced as possible and should not exceed
rated current on any one leg.
GENERATOR PRODUCES MECHANICAL NOISE
CAUSE CHECK AND REMEDY
Defective bearing Replace bearing.
Loose or misaligned coupling Tighten, realign, or replace coupling.
Belt slap or loose guards Check belt tensioning. Check belt guard fasteners.
EQUIPMENT RUNS NORMALLY ON UTILITY POWER,
BUT WILL NOT RUN ON GENERATOR SET
CAUSE CHECK AND REMEDY
Distorted voltage waveform Analyze load. Excessive SCR (thyristor) loading will cause distortion. Some equipment
may be sensitive to distorted waveforms. Refer to Marathon Electric..
Improper generator voltage or frequency Check name plates of devices comprising the load. Compare required voltage and
frequency with that of the generator. Adjust driver speed and/or generator voltage as
necessary to match generator output to load requirements.
Compare required voltage, frequency, and KVA with generator nameplate to ensure adequate generator capacity. If in
doubt, consult Marathon Electric for information regarding generator capacity.
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