Fuji Electric EW32EAG - Page 99

97
5
Maintenance inspections
5-1 Faults and causes
Continued
Type of fault Fault status or location Possible cause Countermeasure
Faulty
operation due
to overcurrent
Faulty operation at higher than the
specified operating current
s,ACKOFCOORDINATIONWITHANUPSTREAMCURRENTLIMITINGFUSE
or with an upstream circuit breaker.
s!MBIENTTEMPERATUREISEXTREMELYLOW
s4HEAMMETERGIVESANINCORRECTREADINGBECAUSEOFHIGH
frequency current.
Re-evaluate coordination or change the
selection.
Check the current correction.
Accessory
fault
Motor operating mechanism fault s)MPROPERCONTROLCIRCUITCABLECONNECTIONCAUSESFAULTY
operation.
s)MPROPERCONTROLCIRCUITCABLECONNECTIONCAUSESOPERATION
to start and stop repeatedly. (Snake circuit formed by
connecting the control signal circuit in parallel.)
Inspect and repair the cables. *
s!DROPINVOLTAGEDUETOINSUFlCIENTCAPACITYONTHEPOWER
supply circuit cable causes faulty operation.
s)NSUFlCIENTCAPACITYOFTHECONTROLCIRCUITPOWERSUPPLY
Use heavier gauge cable.
Increase the power supply capacity
(transformer capacity, etc.).
s-AKERUNANDRESETDONOTWORKPROPERLYBECAUSETHE
moving distance of the control mechanism is not properly
adjusted.
Re-adjust the stroke. *
Shunt trip device fault s!DROPINPOWERSUPPLYVOLTAGEDUETOINSUFlCIENTPOWER
capacity for the control circuit causes faulty operation.
s!DROPINPOWERSUPPLYCURRENTDUETOINSUFlCIENTPOWER
supply capacity causes faulty operation.
Increase the power supply capacity. *
s#ONTINUOUSEXCITATIONANINCORRECTCOILRATINGANDFAULTYCOIL
anti-burnout contact operation or coil burnout due to welded
contacts.
Replace the coil and replace the
contacts with coil anti-burnout
contacts. *
Undervoltage trip device fault s4HE-##"DOESNOTTRIPDUETORESIDUALMAGNETICmUXAND
no voltage.
s4HE-##"DOESNOTTRIPDUETOANIMPROPERLYMOVINGSTROKE
and no voltage.
Repair or replace with a new part. *
Auxiliary switch and alarm switch
fault
s#URRENTEXCEEDINGTHEMICROSWITCHCONTACTRATINGBURNSOUT
the contacts or welds them together.
Replace the accessories and insert
a control relay to reduce the load on
internal switch contacts.
s!NIMPROPERMICROSWITCHMOVINGSTROKECAUSESFAULTY
operation.
Replace or repair the microswitch. *