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Risk of electric shock or energy hazard. Parts inside this UPS are energized by the flywheel even when the AC power is disconnected. |
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The flywheel cabinet has two sources of voltage. Control AC voltage and the DC Bus.
The following steps are written for high risk electrical maintenance of the cabinet components located behind the locked doors. Follow these steps before performing maintenance on internal components. It is necessary to shut down all inputs to the flywheel cabinet for this operation, both AC and DC. The customer load will be unprotected.
- Brake the flywheel.
Brake the flywheel if the unit is going to be shut down over 20 minutes. To brake the flywheel press "control-x" in UPSView.
- Place the UPS in Internal Bypass Mode.
The UPS must be placed in the internal bypass mode before any work is done to the cabinet. Refer to the procedure titled Systems Operation, Testing and Adjusting, RENR7654-00, "Transfer to Bypass".
- Discharge the DC Bus.
Let the DC Bus draw down to below 24VDC.
- Unlock the Doors and Open the Doors.
Open the doors of the cabinet by using a 5/16" hex key on the upper and lower latches.
- Place the DC Disconnect Switch in the Open position.
Use the DC Disconnect Handle on the metal safety shield in the middle to disconnect the DC Bus.
Verify that the green light is on before operating the DC Disconnect Switch Handle.
- Place the AC Circuit Breaker in the Open position.
Open the circuit breaker (CB1) located on the lower left panel of the flywheel cabinet.
- Discharge the capacitors.
Allow the capacitor banks in the UPS to draw down for 10 minutes.
- Remove the metal safety shields.
There are three metal safety shields covering the components in the cabinet. Remove the shields, if required.
- Detach the Cable Harness.
Detach the cable harness from the indicators on the metal safety panel located in the middle.