Table of Contents
Advertisement
Continued from previous page
Short circuit
Probable fault cause
------------------------------------------------------------------------------------------------------
Probable fault cause
------------------------------------------------------------------------------------------------------
Alarms and trips in the event of short circuit phase-phase, phase-earth
and overcurrent.
Short circuit phase-phase or
phase-earth (earth fault)
MiniMax trips immediately.
- Motor winding fault
Measure motor resistance; it should be identical on all phases.
- Short circuit between phases in the cable
- Earth fault in the motor or cable
Overcurrent
MiniMax limits thr current at 4 A and trips then after 4-5 s.
- The motor is too small in relation to rotor diameter
- Rotor rotation sluggish
- Damaged motor, e.g. bearing fault
Measure current.
NOTE! Precise voltages and amperages can only be obtained with a
moving-iron instrument.
9
Advertisement
Table of Contents
