Danfoss VLT FC Series Service Manual page 115

Test Procedures
20.0
15.0
10.0
5.0
0.0V
-5.0
-10.0
-15.0
-20.0
-100.0 us
Illustration 8.16 Gate Signal Waveform from Gate Drive Card
IGBT gate signal measured on the gate drive card: 5 V per
division vertical scale, 50 ms per division time scale. Unit
running at 30 Hz.
An incorrect reading of a gate signal indicates that the
gate drive card is defective or the signal has been lost
before arriving at the gate card. The gate signals can then
be checked with the signal test board to verify their
presence from the control card to the power card as
follows.
8.00
6.00
4.00
2.00
0.00V
-2.00
-4.00
-6.00
-8.00
-100.0us
Illustration 8.17 Gate Signal Waveform from Signal Test Board
MG94A502
Service Guide
Input A
5 us/Div.
1.
2.
3.
The waveform in Illustration 8.17 is the correct result.
Input A
5 us/Div.
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Insert the signal test board into power card
connector MK104.
With scope probe common connected to terminal
4 (common) of the signal board, measure 6 gate
signals at signal board terminals 25–30.
Place the drive in run mode at 30 Hz.
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