UPS 750 Uninterruptible Power Supply Caterpillar

The following steps in this section must be used before removing or performing maintenance on any internal components. The steps are defined for electrical high risk maintenance of the cabinet components located behind the locked doors.

All input to the UPS must be shut down during maintenance. Preparing the system for maintenance will require de-energizing the customer load.

1. Use "Control-X" in UPSView to brake the flywheel in on-line mode if the unit is going to be shut down over 20 minutes.

2. Verify that braking is complete. The flywheel must be at zero rpm to continue.

3. Put the UPS into "Internal Bypass". Turn the key on the SIO cabinet to "Bypass".

4. If access to upper components is required, such as the switches, then the UPS must be de-energized.

   Note: Opening the upstream breakers to the bypass cabinet will de-energize the customer load.

5. Lock out and tag out all breakers upstream of the SIO cabinet.

   Note: The cabinet must be de-energized to work on switch components in the bypass cabinet. Refer to Operation and Maintenance Manual, SEBU8859, "Setup Procedures and Initial Adjustments" for shutdown procedures.

6. Discharge the capacitors. Allow the capacitor banks in the UPS to dissipate power for 5 minutes.

7. Unlock the system doors that are required. Open the door of the cabinet by using a hex key on the latches on the right side of the door.

8. Remove the lower metal safety shield that is covering the lower components of the cabinet.