Voltage Is Fluctuating; Operates Satisfactorily When Cold, But Shuts Down When Warm; Builds Voltage From Startup,Then Goes To Low (Residual) Voltage; Equipment Runs Normally On Utility Power, But Will Not Run On Generator Set - Marathon Electric MAGNAMAX Installation, Operation And Maintenance Manual

VOLTAGE IS
FLUCTUATING
OPERATES
SATISFACTORILY
WHEN COLD, BUT
SHUTS DOWN WHEN
WARM
BUILDS VOLTAGE
FROM STARTUP,THEN
GOES TO LOW
(RESIDUAL) VOLTAGE
EQUIPMENT RUNS
NORMALLY ON UTILITY
POWER, BUT WILL NOT
RUN ON GENERATOR
SET
Incorrect Speed
Unstable Speed
Voltage Regulator Stability
Defective / Loose
Connections
Defective Diodes, Surge
Suppressor or Generator
Windings
Remote Voltage Adjust
Defective Regulator
Regulator Shutdown on
Over Temperature
Regulator Protective
Circuit is Operating
Voltage Waveform is
Distorted
54
Verify speed with tachometer or
frequency meter.
Verify governor stability.
Adjust regulator stability.
Refer to regulator manual.
Inspect all wiring for loose or dirty
connections.
Test generator with constant
excitation (12-volt battery test).
Check operation. Refer to regulator
manual.
Replace regulator. Refer to
regulator manual.
Correct cooling problems. Refer to
regulator manual.
Check indicators on regulator.
Correct problems and adjust as
required. Refer to regulator manual.
Analyze load. Excessive SCR
(Thyristor) loading will cause
distortion. Some equipment may be
sensitive to distorted waveforms.
Refer to Marathon Electric.