Danfoss VLT CDS 302, Troubleshooting Manual

Page: 15 / 18

Static test procedures
Step 4 Now reverse the meter leads, i.e. connect the
negative terminal of the meter lead to the
negative DC bus. • Connect the positive terminal of the meter lead
to the input terminals L1, L2, L3 in turn.
• The multimeter should show diode open.
Figure 15: The multimeter
should show diode open
Figure 16: The multimeter
should show diode open
Figure 17: The multimeter
should show the diode drop
of around 0.4 volt on the
three terminals
Figure 18: The multimeter
should show open diode
Note: A diode drop reading will vary depending on the model of the ohm meter
IGBT static test
IGBT's are placed on the output of the CDS drives
Step 1
Step 2
Step 3
• Connect the positive terminal of the multimeter
lead to the positive DC bus.
• Connect the negative terminal of the
multimeter lead to the motor terminal U, V, W
in turn.
• The multimeter should show the diode open.
Now reverse the meter leads, i.e. connect the
negative terminal of the meter lead to the
positive DC bus. • Connect the positive terminal of the meter lead
to the motor terminals U, V, W in turn.
• The multimeter should show the diode drop
of around 0.4 volt on the three terminals.
Now repeat the procedure by connecting to the
negative DC bus in order to test the second set
of IGBTs. • Connect the negative terminal of the
multimeter lead to the negative DC bus.
• Connect the positive terminal of the multimeter
lead to the motor terminal U, V, W in turn.
• The multimeter should show open diode.
15
FRCC.PC.036.A2.02
Check List