Rockwell Automation 7000A PowerFlex Medium Voltage Drive (A-Frame) - Classic Control - Manual (Page 345)

Component Definition and Maintenance 6-41
7000 “A” Frame 7000A-UM150F-EN-P –June 2013
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
The yellow LED (LED 1) on the SGPDB indicates that the SCR being
controlled has a gating current flowing which is used to turn the SCR on.
Self-Powered Gate Driver
Board – SPGDB