Dings Magnetic Group Stationary Electro Overhead Magnets - Manual (Page 11)

Revised January 19, 2011
ELECTRICAL TROUBLESHOOTING
Before starting, first follow this preliminary checklist:
1. Check all fuses and/or circuit breakers. For fuses, use a dual element time delay fuse
with a maximum of 175% of the full load current to protect the input side of the rectifier.
If 175% of full load amps does not correspond to a standard fuse size, select the next
larger standard fuse size (but do not exceed 225%). For circuit breakers, use a n
inverse time circuit breaker with a maximum of 250% of full load current. If 250% does
not correspond to a standard circuit breaker size, select the next larger standard circuit
breaker size (but do not exceed 400% for 100 amps or less).
2. Check all wiring for loose or broken connections.
3. Visually inspect all internal rectifier components.
4. If equipped with a starter, check all overloads (bi-metallic components) to see if any
have tripped. Wait several minutes before resetting.
5. If equipped with a starter, check to see if correct heaters for selected voltage are
installed and that load does not exceed nameplate rating.
6. Do not ground the DC circuit supplying the magnet or damage will occur.
WARNING
The following procedures should be performed by a qualified electrician. Extreme caution
should be used as live electrical equipment will be tested. Before starting the testing
procedure, turn off and lock-out any surrounding equipment that may pose a danger during
testing. If the magnet is of the self-cleaning type, turn off and lock-out the power to the self-
cleaning belt motor. The following instructions are for standard 230 VAC or 460 VAC, 3 phase,
60 Hz rectifiers. For special input voltages, consult factory.
STEP 1
Disconnect the DC cable leads to the magnet AT THE RECTIFIER TERMINAL BLOCK inside
the rectifier cabinet. Turn on the power to the rectifier. Measure the AC input voltage to the
rectifier at the terminal block.
1st Reading Phase 1 to Phase 2 Volts:
2nd Reading Phase 2 to Phase 3 Volts:
3rd Reading Phase 3 to Phase 1 Volts:
If all three voltage readings are within the following tolerances, the power supplying the rectifier
is OK. Go to Step 2.
230 VAC + 5% for 230 VAC input rated rectifiers.
460 VAC + 5% for 460 VAC input rated rectifiers.
If one or more of the voltage readings are out of tolerance, the power supplied to the rectifier is
incorrect and must be corrected.
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