Troubleshooting,continued
MotorTroubleshooting
MotorTroubleshooting
56 Manual BBB4_ENG_01_2016_991301
Problem with the Motor Possible Causes SuggestedRemedy
Load is
disconnected
but motor does
not rotate
Makes a
“groaning” sound
Faulty switch contact
Adjustthecontact
Blown fuse Replace fuse
One phase wire of the power supply
open
Rewire connection
Stator coil open Repair by rewinding or replacing the stator assembly
Stator and rotor touching due to bearing
housing wear
Replace the bearing and bracket
Starts in either direction
when turned by hand
Three-phase is operating as singlephase Consult the power source with a voltmeter
Doesn’t make any
noise
Stator coil open Repair by rewinding or replacing stator assembly
External power failure
Contact the local power company.
Open connection wire
Faulty Switch contact
Faulty Starter contact
Check the source wiring
Adjustthecontacts
Rotates with
the load
disconnected
but:
Rotates in the wrong
direction
Connection error Change any two of the three-phase source connections
Fuse blows Shorted lead wire Replace fuse and rewire short
Speed does not increase Faulty starter contact
Replaceoradjuststartercontact
Makes a “groaning”
sound
Overcurrent/Overheating due to Rotor
and Stator touching
Repair by rewinding or replacing stator assembly
Overcurrent due to one phase of Stator
Coil shorted
Replace the stator winding
Makes a highpitched
“metallic” noise
Faulty bearing Replace the bearing
Rotates when
the load is
disconnected
but when the
load is
connected:
Switch overheats
Insucientswitchcapacity Replace with switch having the rated capacity
Overload Decrease load to the rated value
Fuse blows Insucientfusecapacity Replace with fuse having the rated capacity
Overheats
Overload Decrease load to rated value
Voltage drop Consult with local power company
Speed suddenly drops
Voltage drop Consult with local power company
Overload Decrease load to rated value
Stops Bearing damaged by overheating Replace the bearings