BENSHAW RediStart EXEXMVRMX3 Series, User Manual

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8 - TROUBLESHOOTING & MAINTENANCE
8.7.3 SCR Gate to Cathode Test
To perform the gate to cathode test, attach the ohmmeter to SCRs like in the picture shown below to measure the resistance between the
red and white SCR gate leads.
If an SCR measures less than 8 ohms but not 0 ohms, the SCR still may be good. If any of the recorded values are 0 ohms then that SCR
has failed. An ohmmeter can only determine failed devices; an SCR tester is required to verify proper operation of the device.
z
NOTE: If at any time during this procedure it is necessary to remove any of the red and white SCR gate leads from the firing card,
care must be taken to insure that these leads are reconnected to the terminal they were removed from.
z
NOTE : If at any time these resistance readings are outside of the above specified values consult factory.
Figure 50: SCR Gate Test
Test Ohm Meter Reading Results
Gate to cathode for each SCR
8
W
to 50
W
Pass
Less than 8
W
or more than 50
W
Fail
Table 18: Ohmmeter Position for SCR Gate Test