Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 336)

6-46 Component Definition and Maintenance
7000-UM150I-EN-P – June 2013 7000 “B” Frame
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