134 • vacon
FAULT TRACING
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9
9.3
DC link test (without motor)
NOTE: There will be dangerous voltages present during this test!
1
Read carefully the safety instructions in Chapter 1 and above and follow them.
2
Connect a variable DC power supply to DC+ and DC– terminals. Make sure that all polarities are
correct.
3
Slowly charge up the DC link to nominal voltage. Allow the system to remain at this level for at
least one minute and check current.
4
If possible, continue increasing the DC link voltage up to the trip limit. Fault F2 (see chapter 9)
should occur at 911 VDC (400…500-volt units) and at 1200 VDC (525…690-volt units). Do not in-
crease the voltage over the trip limit.
5
Bring the power supply voltage back to zero. Allow sufficient time for the capacitors to dis-
charge.
6
Check the DC bus voltage with a multimeter. When you read zero volts disconnect the power
supply and reconnect all wires to the phase module.
7
If the phase module has been de-energized for an extended period of time (six months or longer)
allow this voltage to remain for a minimum of 30 minutes – even 4 hours if time permits.
Through the above test procedure, two things are achieved: 1) It allows the caps to partially reform
due to storage and shipping; 2) It allows any device failures to evidence themselves with a low power
failure.
