UPS Major Preventive Maintenance Inspection
- Perform a complete visual inspection of the equipment including subassemblies, wiring harnesses, contacts, cables and major components. Check air filters for cleanliness.
- Check module(s) completely for the following (if applicable):
- Rectifier and inverter snubber boards for discoloration.
- AC Capacitors for swelling or leaking oil.
- DC Capacitor vent caps that have extruded more than 1/8”.
- Record all voltage and current meter readings on the UPS module and the system control cabinet (when applicable). Verify with calibrated DVOM.
- Measure and record harmonic trap filter currents.
- Check the inverter and rectifier snubbers for burned or broken wires.
- Check all nuts, bolts, screws and connectors for tightness and heat discoloration.
- Check fuses on the DC capacitor banks for continuity (if applicable).
- With customer approval, perform operation test of the system including unit transfer, battery discharge and generator interface test.
- Calibrate and record all electronics to system specifications.
- Measure and record all low-voltage power supply levels.
- Measure and record phase-to-phase input voltage and currents.
- Review, clear and reset all diagnostic alarm histories, where applicable.
- Record all input, output, and battery voltages and currents.
- Furnish completed data sheets and report any problems found during the PM inspection.
- Review system performance with customer.
Note 1: Preventive Maintenance usually requires a module shut-down to ensure electrical connection integrity.
Note 2: Customer should check air filters monthly for cleanliness and replace as necessary.
Note 3: Above maintenance does not include System Control Cabinet, Power Tie Cabinet, Breaker Cabinets, Load Bus Sync or Maintenance Bypass Cabinets.