How will your UPS system hold up?

Is your company’s support power adequate to sustain it through protracted outages? Is your support system, particularly the battery—the heart of the system—expertly maintained? Do your maintenance personnel, whether in-house or contracted, know the subtle signs of impending trouble?


Can you afford to take the chance?

A UPS system is comprised of the electronics and the battery system. According to UPS manufacturers, the battery system is the root cause of failure 9 out of 10 times. Battery maintenance is usually performed on a quarterly, semi-annual or annual schedule that includes voltage checks, impedance testing, specific gravity readings, rewatering, resistance testing, retorquing connections and a cleaning of the battery system is performed.

Maintenance on the UPS systems electronics should also be performed on a regular basis to ensure the integrity of your backup system. A typical maintenance visit consists of:


Semi-Annual Service

Typical tasks performed during a Semi-Annual service visit include:


  • Check all breakers. Temperature, connections and associated controls. Repair and/or report all high temperature areas.
  • Complete visual inspection of the equipment including subassemblies, wiring harnesses, contact, cables and components.
  • Check air filters for cleanliness.
  • Check module(s) completely for rectifier and inverter snubber boards for discoloration.
  • Check power capacitors for swelling or leaking oil and DC capacitor vent caps that have extruded more than 1/8 inch.
  • Record all voltage and current meter readings on the module control cabinet or the system control cabinet.
  • Measure and record harmonic trap filter currents.

Annual Service

Typical tasks performed during an annual service call include all the tasks done during a semi-annual visit plus the following:


  • Check inverter and rectifier snubbers for burned or broken wires.
  • Ensure all nuts, bolts, screws and connectors for tightness and heat discoloration.
  • Verify fuses on the DC capacitor deck for continuity (if applicable).
  • With customer approval, perform operational test of the system including unit transfer and battery discharge.
  • Check and record all electronics and bring to system specifications as needed.
  • Install or perform and Engineering Filed Change Notices (FCN) as needed.
  • Measure and record all low-voltage power supply levels.
  • Measure and record phase-to-phase input voltage and currents.
  • Review system performance with customer to address any questions and to schedule repairs.