Insufficient residual voltage - Excite the rotor using a battery.
Improper connection - Correct the connection.
Faulty molded rectifier bridge - Replace the rectifier bridge.
Low speed - Reset the speed to the nominal.
Faulty winding - Check the winding resistance and rewind if required.
Q. Low no-load voltage ?
Low speed - Reset the speed to the nominal.
Air - gap of compound too small - Regulate the compound air gap.
Faulty rotating rectifier - Replace the rotating rectifier.
Faulty winding - Check the winding resistance and rewind if required.
Q. Low voltage on load ?
Low speed at full load - Set the rated speed of the prime mover.
Compound defective - Check and if necessary change the compound unit.
Q. Excessive overheating of one or both bearings (temp. of bearings over 80 C) (with or without noise) ?
Set misalignment - Align the set properly.
Bearing loose in end shield housing - Replace the faulty end shield.
Q. Excessive overheating of alternator frame ?
Air flow (inlet-outlet) partially clogged or hot air is being circulated either from alternator or prime mover - Check air inlet - outlets of the alternator.
Alternator operating at high voltage at load - Operate at specified load.
Alternator overloaded - Operate at specified load.
Load PF less than 0.8 lag - Correct the load power factor.
Q. Excessive vibration and humming noise coming form the alternator ?
Three phase alternators is single phase loaded in excess of acceptable limits - Check and correct the load.
Q. Smokes, spark or flames coming from the alternator ?
Short circuit in the external circuit (including wiring between alternator and control board) - Stop the set immediately.
Object fallen into the machine.
Short circuit or flash in the stator winding
Q. Alternator damaged by a significant impact which is followed by humming and vibration ?
Short circuit in external circuit - Stop the gen-set immediately.
