Siemens G120P Technical Manual page 89

Siemens
Building Technologies
Rectifier tests
Positive measuring Negative measuring
point point
L1 DC-
L2 DC-
L3 DC-
DC + L1
DC + L2
DC + L3
DC- L1
DC- L2
DC- L3
IGBT bridge test
Positive measuring Negative measuring
point point
U DC +
V DC +
W DC +
U DC-
V DC-
W DC-
How to proceed if a fault is discovered
 The variable speed drive has failed one of these tests:
Remove the Power Module (power unit) in order to replace or repair it.

 A short circuit is present at the input rectifiers or at components of the IGBT
bridge:
Check the state of fuses in the supply line, of contactors, disconnectors or of

the motor itself.
Remember that an apparently open circuit can also occur following a component
short-circuit and the resulting strong flow of current.
Service, maintenance and fault rectification
Fault rectification
Expected result
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode aperture – typically 0.3 – 0.5V
Diode aperture – typically 0.3 – 0.5V
Diode aperture – typically 0.3 – 0.5V
Expected result
Diode aperture – typically 0.3...0.5 V
Diode aperture – typically 0.3...0.5 V
Diode aperture – typically 0.3...0.5 V
Diode block – OL/High impedance
Diode block – OL/High impedance
Diode block – OL/High impedance
8
OK
⃞
⃞
⃞
⃞
⃞
⃞
⃞
⃞
⃞
OK
⃞
⃞
⃞
⃞
⃞
⃞
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2016-03-17