Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C-Frame) - ForGe Control - Manual (Page 311)

Rockwell Automation Publication 7000L-UM301D-EN-P - June 2014 311
Component Definition and Maintenance Chapter 5
Self-Powered Gate Driver
Board – SPGDB Description
This board is used in drives where SCRs are used as the rectifying device on the
input of the drive. The SCRs require a gating pulse in order to turn on, and this is
achieved by using the SPGDB.
The SPGDB receives its command from the drive processor, via a light signal,
which is transmitted through a fiber optic cable. The power source for the
SPGDB is from the snubber network of the SCR, a patent pending design of
Rockwell Automation. This unique design gives the SPGDB the ability to
conserve the amount of energy that it supplies to the SCR. This reduces the
amount of energy required by the drive to operate, thus making the drive more
efficient.
Also, this board will determine the health of the SCR. It has the hardware
necessary to diagnose the condition of the SCR. This status is relayed to the
processor via a fail-safe light signal transmitted through a fiber optic cable.
Board Calibration
No field calibration is required for this board.
Test points description
TP1 – SCR gate output (attach oscilloscope between TP1 and TP2 to see gating
pulses).
TP2 – SCR cathode output.
TP3 – Common reference point for all other test point measurements, except for
TP1, which uses TP2 as its reference point.
TP4 – The positive 20 V rail used for the SPGDB operation.
TP5 – The positive 5 V rail used for the SPGDB operation.
TP6 – The sense voltage taken from the sense resistor across the SCR being
controlled.
TP7 – Trigger signal, which remains active for a fixed period of time after the
SCR being controlled, has turned on and the voltage across it has collapsed.
TP8 – Internal gating signal that indirectly turns on the SCR that is being
controlled.
TP9 – Gating signal received from the commanding drive control board,
through the appropriate fiber optic cable.