Fuji Electric BW32AAG - 5-2 Periodic Inspections

96
5
Maintenance inspections
5-1 Faults and causes
5-1 Faults and causes
Table 5-1 shows the appropriate countermeasure to take for faults that occur during MCCB operation.
Table 5-1 Troubleshooting
Type of fault Fault status or location Possible cause Countermeasure
Abnormal
heat
Abnormally high terminal
temperature
s,OOSETERMINALORCONDUCTORSCREW Tighten the screw. *
Burned insulation material in the
terminal section
s(EATGENERATEDBYEXCESSIVECONTACTRESISTANCE
s,OOSETERMINALORCONDUCTORSCREW
Repair or replace with a new part. *
Abnormally high molded case
temperature (exceeding 70°C)
s(EATGENERATEDBYEXCESSIVECONTACTRESISTANCE Replace with a new part. *
s3IGNIlCANTHIGHERHARMONICCURRENTINTHELOADCURRENT Insert reactors to reduce the distortion
factor or re-evaluate the rated current
selection.
s(EATGENERATEDINTHESOLENOIDCOILHYDRAULICMAGNETIC
type) by high-frequency current (400Hz, etc.)
Re-evaluate the rated current selection
or use a thermal-magnetic type. *
s,OOSEINTERNALSCREW Replace with a new part. *
s(IGHCURRENTDENSITYCAUSEDBYABROKENBRAIDEDWIREWIRE
broken due to corrosive gas in the operating environment)
Use parts treated for anti-corrosion.
Faulty
operation
Making fault s4HE-##"HASNOTRESETAFTERTRIPPING Reset the MCCB.
s6OLTAGEHASBEENAPPLIEDTOASHUNTTRIPDEVICE Inspect the wiring. *
Reset fault s4HEUNDERVOLTAGETRIPDEVICEHASNOTBEENENERGIZED Turn on the power supply.
s4HE-##"HASNOTCOOLEDSUFlCIENTLYFOLLOWINGAN
overcurrent trip.
Let the MCCB cool and then reset it.
s4HEBIMETALELEMENTHASCORRODEDORISOTHERWISEDEFORMED
s4HENUMBEROFTRIPOPERATIONSHASEXCEEDEDTHEDURABILITYOF
the MCCB. (The shunt trip device or undervoltage trip device
tripped too many times.)
Replace with a new part. *
s&AULTYMECHANISM
Breaker
tripping
The breaker trips in a closed
circuit with less than the rated
current.
s4HEAMBIENTTEMPERATUREISABNORMALLYHIGH#OR
higher).
Use ventilation or some other means to
lower the ambient temperature.
s(EATGENERATEDBYALOOSETERMINALSCREWWITHTHERMAL
magnetic type)
Tighten any loose screws. *
s(EATGENERATEDINSIDETHE-##" Replace with a new part. *
s3HOCKANDVIBRATION Take action like cushioning to reduce
shock and vibration.
s4HELOADCURRENTHASEXCEEDEDTHERATEDCURRENT
(Example: The motor is running in overload, undervoltage or
overvoltage conditions).
Re-evaluate the rated current selection.
Starting current trips the MCCB s%ITHERMOTORSTARTINGCURRENTORTRANSFORMEREXCITINGINRUSH
current trips the MCCB.
Change the instantaneous trip current
setting or the rated current. *
s4RANSIENTINRUSHCURRENTDURINGTHECHANGEOVERFROMSTARTO
delta connection trips the MCCB.
s)NCHINGOPERATIONINSTANTLYTRIPSTHE-##"
s#APACITORINRUSHCURRENTMERCURYLAMPORPHASEADVANCE
capacitor), incandescent lamp inrush current, or fluorescent
lamp starting current instantly trip the MCCB.
s)NTERMITTENTOPERATIONSPOTWELDERORMOLDINGEQUIPMENT See 3-7-2, Chapter 3.
s(IGHSTARTINGCURRENTCAUSESANINVERSETIMEDELAYTRIP
s!LONGSTARTINGTIMECAUSESANINVERSETIMEDELAYTRIP
Change the rated current. *
s!BNORMALLARGECURRENTmOWSWHENTHECIRCUITCLOSES3HORT
in a load side circuit)
Inspect the circuit and eliminate the
cause.
s!LAYERINSULATIONFAULTOCCURSINTHEMOTOR
Repair or replace the motor. *
s!MALFUNCTIONOCCURSBECAUSEACONTROLCIRCUITINASHUNTTRIP
or undervoltage trip device is connected improperly.
Inspect wiring and repair the cables. *
Buzzing
sound
Current flow is above the rated
level.
s4HESOLENOIDCOILINTHE-##"OPERATESBECAUSEOFA
distorted current waveform (Inverter connected to the load).
Change the rated current. *
Note: * Do not inspect or take any other action until you are sure there is no voltage applied to the MCCB terminals.