Rockwell Automation 7703E Medium Voltage SMC OEM Components - 10-15 kV - Manual (Page 44)

44 Rockwell Automation Publication 7703E-IN001E-EN-P - July 2014
Chapter 7 Final Test Procedures
Figure 22 - Gate Pulse Detail – Typical SCR (ABB)
Figure 23 - Gate Pulse Test Waveform
10. If no pulse is observed, and the yellow LED is lit, check for a shorted gate
on the SCR by removing the green plug and connecting an ohmmeter to
the gate leads. If the LED is not lit, and the circuit voltage is as specified in
step 8 (above), pinch the tab on the blue fiber-optic connector and
carefully pull it straight out of the receiver. The end of the connector
should glow red to indicate the presence of a gate signal.
If it does not, remove the other end of the cable from the interface board
and check that the grey transmitter is emitting red light. If it is, the fiber-
optic cable must be replaced. If it isn’t, the interface board should be
replaced.
ATTENTION: Do not look directly into the end of the fiber optic cable.
Microseconds
Vo
lts
Microseconds