SPX Cooling Technologies MARLEY CLASS 800 - Manual (Page 22)

22
Troubleshooting
Trouble Cause Remedy
Motor Will Not Start Power not available at motor terminals • Check power at starter. Correct any bad connections
between the control apparatus and the motor.
• Check starter contacts and control circuit. Reset overloads,
close contacts, reset tripped switches or replace failed control
switches.
• If power is not on all leads at starter, make sure overload
and short circuit devices are in proper condition.
Wrong connections Check motor and control connections against wiring diagrams.
Low voltage Check nameplate voltage against power supply. Check
voltage at motor terminals.
Open circuit in motor winding Check stator windings for open circuits.
Motor or fan drive stuck Disconnect motor from load and check motor and Geareducer
for cause of problem.
Rotor defectve Look for broken bars or rings.
Unusual Motor Noise Motor running single-phase Stop motor and attempt to start it. Motor will not start if single-
phased. Check wiring, controls, and motor.
Motor leads connected incorrectly Check motor connections against wiring diagram on motor.
Ball bearings Check lubrication. Replace bad bearings.
Electrical unbalance Check voltages and currents of all three lines. Correct if
required.
Air gap not uniform Check and correct bracket fits or bearing.
Rotor unbalance Rebalance.
Cooling fan hitting guard Reinstall or replace fan.
Motor Runs Hot Wrong voltage or unbalanced voltage Check voltage and current of all three lines against nameplate
values.
Overload Check fan blade pitch. See Fan User Manual. Check for
drag in fan drive train as from damaged bearings.
Wrong motor RPM Check nameplate against power supply. Check RPM of motor
and gear ratio.
Bearings overgreased Remove grease reliefs. Run motor up to speed to purge
excessive grease.
Rotor rubs stator bore If not poor machining, replace worn bearing.
Wrong lubricant in bearings Change to proper lubricant. See motor manufacturer's
instructions.
One phase open Stop motor and attempt to start it. Motor will not start if single-
phased. Check wiring, controls, and motor.
Poor ventilation Clean motor and check ventilation openings. Allow ample
ventilation around motor.
Winding fault Check with Ohmmeter.
Bent motor shaft Straighten or replace shaft.
Insufficient grease Remove plugs and regrease bearings.
Deterioration of grease, or foreign
material in grease Flush bearings and relubricate.
Bearings damaged Replace bearings.
Motor Does Not Come Up
To Speed Incorrect fan blade pitch See Fan User Manual for blade pitching instructions.
Voltage too low at motor terminals
because of line drop Check transformer and setting of taps. Use higher voltage on
transformer terminals or reduce loads. Increase wire size or
reduce inertia.
Broken Rotor bars Look for cracks near the rings. A new rotor may be required.
Have motor service person check motor.