What is an RB-IGBT?

It stands for Reverse Blocking Insulated Gate Bipolar Transistor. Reverse-parallel connection of RB-IGBT enables both way switching. It is incorporated in Fuji Electric’s exclusive AT-NPC (Advanced T-type Neutral Point Clamped) 3-level inverters, to increase the power conversion efficiency because there are less current passing elements.

What kind of batteries work with Fuji Electric UPSs?

Our UPSs work ideally with lead-acid wet cells, VRLA batteries, lithium-ion batteries of all chemistries, and flywheels. NiCd batteries are also an option, contact the factory for more information.

What preventative maintenance is required for Fuji Electric UPSs?

Fuji Electric recommends two PMs per year, one “minor” PM to check batteries, and inspect the unit online, and one “major” PM to send the load to bypass, do a thorough mechanical inspection and cleaning, full diagnostic test, and of course inspect the batteries as well.

Do your capacitors require regular replacement?

No, our AC and DC capacitors are designed for the life of the unit, and no regular replacements are required.

Do Fuji Electric UPSs use redundant fans?

Yes, all of our products have redundant fans.

What would cause the CTR-M to turn off (fan related, Open the bypass)?

It depends on the thermal sensor mounted near SCR. When the thermal sensor operates, stop the SCR gate drive. Then, UPS will display “WARNING” on LCD, and store a log “TEMP ALARM (STS)”. In the case of the parallel redundant UPS, the UPS that detects the abnormal temperature is disconnected (parallel-off). And the normal UPS(s) […]

Are the 2 fans in the front of the cabinet on the SCR heatsink fed from the same power supply?

Yes. 2 fans are connected to one power supply. And 3 power supplies are connected to one control transformer.

It looks like there are 3 fan power supplies and each power supply runs 2 fans. (6 fans total)

Yes, 4 fans on the top and 2 fans on the front for SCR. Fuji has verified a single power supply failure. That means that 2 fans failure simulated.

Is an alarm produced for a single fan failure?

No, it is not. Only one type of caution message is displayed. Please visually check it because you do not know which fan has failed.

Please provide a brief comment on a single fan failure in a CTR-M.

Each fan has a speed alarm. When any one alarm is detected, UPS will display “CAUTION” on LCD, and store a log “CTR FAN ERROR”. CTR-M continues running.