Danfoss VLT CDS 302, Troubleshooting Manual

Page: 14 / 18

Static test procedures
POWER MUST BE OFF / MAINS AND MOTOR
CABLES DISCONECTED!
Verification of: Rectifier (input, mains) / IGBT
(Output, motor)
• If rectifier or IGBT fail, the complete power
card has to be exchanged, since in the CDS
drives, the rectifier and IGBT are integrated in
one power card.
Rectifier test (static)
Symptom:
Step 1
Figure 12: Multimeter
should read a voltage drop
of 0,4V
Figure 13: Multimeter
should show diode open
Figure 14: Multimeter
should show a diode drop
of 0,44V
Step 2
Step 3
Failure of the rectifier module will usually result
in blown input line fuses. Procedure to conduct the static test on rectifier:
• Connect the negative terminal of the
multimeter meter lead to the positive DC bus.
• Connect the positive terminal of the multimeter
lead to the input terminal L1,L2,L3 in turn.
• The multimeter should show the diode drop
of around 0.44 volt on the three terminals.
Now reverse the meter leads, i.e. connect
the positive terminal of the meter lead to the
positive DC bus. • Connect the negative terminal of the meter
lead to the input terminals L1, L2, L3 in turn.
• The multimeter should show diode open.
Now repeat the procedure by connecting to the
negative DC bus in order to the test the lower
part of the rectifier bridge which consist of
diodes
• Connect the negative terminal of the meter
lead to the input terminals L1, L2, L3 in turn.
• The multimeter should show the diode drop
of around 0.44 volt on the three terminals.
14
FRCC.PC.036.A2.02
Check List