Rockwell Automation 7000L PowerFlex Medium Voltage AC Drive (C Frame) - Classic Control - Manual (Page 389)

Component Definition and Maintenance 6-45
7000 “C” Frame 7000L-UM300I-EN-P – June 2013
3. Remove the screws holding the bus bars to the resistor terminals.
The position of the sharing resistor is common on all drive sizes.
The number of snubber resistors varies with the size of drive and
application. Shown below is a three-snubber resistor configuration.
There can be up to 5 snubber resistors on each chill block.
Screws and bus bar
to be removed
Sharing Resistor
Snubber Resistors
Figure 6.36 – Snubber and Sharing Resistor Replacement
4. After removing the bus bars, unscrew the two screws holding
each resistor in place. Measure each resistor on the assembly to
verify which resistors are damaged.
5. Apply a thin layer of Electrical Joint Compound (Alcoa EJC
No.2 or approved equivalent) to the contact faces of the new
resistors 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.
6. Install the new resistor(s) on the chill plate and replace the M4
mounting screws.
7. When all damaged snubber resistors have been replaced, re-
assemble the bus bars with the original hardware.
8. Re-connect any leads that were removed.
9. Install the chill block assembly as described in “Chill Block
Removal and Replacement”. Readjust the clamping load as
described in “Checking Clamping Pressure”.
10. Verify the snubber and sharing resistances.