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

Page 331

Component Definition and Maintenance 6-27

7000 “A” Frame

7000A-UM150F-EN-P –June 2013

A T T E N T I O N

The SCR and SCR SPGD Board can be
destroyed or damaged by static charges.
Personnel must be properly grounded before
removing the replacement SCR and SCR SPGD
Board from the protective anti-static bag that it is
supplied in. Use of damaged circuit boards may
also damage related components. A grounding
wrist strap is recommended for handling sensitive
circuit boards.

I M P O R T A N T

Never adjust the orientation of the SCR using the
Gate and Cathode Leads. These connections are
sensitive and the device orientation should only
be adjusted by turning the device itself.

TO REPLACE THE SCR, FOLLOW STEPS 8-11, and 15-18.

TO REPLACE THE SCR SPGD BOARD, FOLLOW STEPS 12-18.

8. Loosen the tie wrap holding the G-C wire in place, and remove the

device from the assembly.

I M P O R T A N T

Replacement SCRs will be supplied, grouped in
matched sets. This means that all of the SCRs in
a leg have been grouped together based on their
electrical performance. Grouping similarly
matched devices ensures balanced load sharing of
a leg of devices. When replacing the device, it is
necessary to replace all the SCRs in a matched
set, even if only one has failed.

9. Install the new device in the same position and using the same

orientation as the original SCR, and firmly secure the G-C wires with
the same tie wrap.

10. Connect the Gate-Cathode phoenix connector to the Gate Driver

Board.

11. Apply a thin layer of Electrical Joint Compound ( Alcoa EJC No.2 or

approved equivalent ) to the contact faces of the new SCRs to be
installed. The recommended procedure is to apply the compound to
the pole faces using a small brush and then gently wiping the pole
face with an industrial wipe so that a thin film remains. Examine the
pole face before proceeding to ensure that no brush bristles remain.