Rockwell Automation 2364F RGU Precharge Resistor Replacement - Manual (Page 3)

Publication 2364F-5.17 March 1999
RGU™ Precharge Resistor Replacement 3
Preliminary Steps Before replacing any precharge resistors, shut off the power; lockout/tagout
the RGU; and wait five minutes for all voltage to discharge. Open the bay
door to the power structure and remove any Lexan™ shielding that is
covering the precharge resistors.
Replacing Precharge Resistors 1. Using a meter, test the voltage across the AC line, across the DC bus, and
across each of the precharge resistors.
2. Remove the wiring from a resistor to be replaced.
3. Remove the mounting nuts (or screws) from the top and bottom of the
resistor, then remove the resistor from the assembly.
Note: Some resistors may have one end screwed into the frame of the
roll-out unit. For these resistors, remove the nut from the front end, then
unscrew the resistor from the frame.
4. Secure the new resistor into the assembly and torque the mounting nuts
to 14 lb-in / 1.5 N-m (torque screws to 10 lb-in / 1.0 N-m).
5. Connect the leads to the new resistor and torque to 75 lb-in (8.5 N-m).
Repeat steps 2 through 5 for each resistor to be replaced. Schematics of the
precharge circuit wiring can be found in publication 2364F-5.01, if needed.
Figure 1
Typical Precharge Resistor Replacement
!
ATTENTION: If there is any voltage present, remove the
source of the voltage. Check for voltages again before
proceeding to the next step.
Wiring
Connections
Mounting
Nut