Siemens 580 Benutzerhandbuch

- 12 - 

 

 
Between regular maintenance inspections, be 
alert for signs of motor trouble.  Common 
symptoms are listed in the following table. 

 

Correct any trouble immediately and AVOID 
COSTLY REPAIR AND SHUT DOWN. 
 

Usually line trouble. Single phasing at 
starter. 

Check power source.  DO NOT check with 
motor energized!  Check overloads, controls 
and fuses.  Check voltage and compare with 
nameplate rating. 

Under Voltage. 

Check voltage at motor terminals.  Compare to 
nameplate. 

Motor will not start. 

Excessive Load. 

Disconnect motor from load to see if it starts 
without load.  Reduce load or replace motor 
with unit of greater capacity. 

High Voltage. 

Check input voltage. Check for proper 
connections. 

Unbalanced rotor. 

Balance rotor. 

Excessive hum. 

Excessive wear of sleeve bearings. 

Replace bearings.  Check to determine cause 
of wear and replace as necessary.  Check 
alignment. 

Regular clicking. 

Foreign matter in air gap. 

Remove foreign matter. 

Rapid knocking. 

Bad anti-friction bearing or dirt in lubricant. 

Replace bearing, clean grease cavities and 
renew lubricant. 

Misalignment in coupling or feet. 

Realign motor and driven equipment. 

Accumulation of dirt on fan. 

Clean motor. 

Vibration in driven machine. 

Run motor disconnected from driven load and 
check for vibration.  Eliminate source in driven 
equipment. 

Vibration. 

System natural frequency (resonance). 

Alter rigidity of base structure. 

Vibration following motor 
repair. 

Rotor out of balance; balance weights of 
fans shifted on rotor. 

Balance rotor. 

Overload. 

Measure load and compare with nameplate 
rating.  Check for excessive friction in motor or 
complete drive.  Reduce load or replace motor 
with unit of greater capacity. 

Single phase. 

Check current, all phases. 

Dirt in motor. 

Check flow of air.                                       
Check filters if so equipped.                             
Clean motor. 

Unbalanced voltage. 

Check voltage, all phases. 

Motor overheating.  
(Check with thermocouple 
or by resistance method, 
do not depend on touch). 

Rotor rubbing on stator. 

Check air gap.  Repair motor as necessary. 

Hazardous voltage. 

Will cause death, serious injury, 
electrocution or property damage. 

Disconnect all power before working on 
this equipment.