Minuteman Model E2300 UPS

[jackvis]

Has anyone experienced shutdown problems for no apparent reason with this UPS? We have many of these and experience periodic shutdowns with many of them. They will even shutdown with nothing plugged into them. The mfg. claims we probably have a harmonic problem. No doubt we have harmonics, but we don't experience problems with any other equipment. In fact there are other ups in the same headend rooms that operate perfectly fine. This is a school district and these ups are spread all over the city, so the problem is not isolated to one area. I appreciate any help you can provide. Thanks

 

[pqtest]

Re: Minuteman Model E2300 UPS

Hello-

Could you please define what you mean by a "shutdown"? Is the UPS totally off, or simply not producing an output?

I'm not so sure that harmonic distortion is playing a major factor in this case.

Generally, harmonics may prevent the UPS battery(s) from fully charging thereby reducing the runtime, but the electrical circuitry would still be receiving voltage and the UPS should remain on.

I'm not ruling out harmonics, just that I have never seen or read of this as being a typical symptom.

Four things I would check out first are:

1) Any chance students or staff are shutting the units down as part of an energy conservation mentality?

2) Take an o-scope or scopemeter to the electrical receptacles. If the voltage sine wave is heavily distorted, then you may want to verify the readings with a harmonics analyzer. If little or no distortion is present, I would rule out harmonics.

3) Measure the input voltage at the receptacle to make sure that it meets the mfg. requirements.

4) Check your branch circuits- any chance the Minuteman UPS units are on a circuit that is being fed by another larger UPS somewhere in the facility? Like surge suppressors, UPS systems should not be daisy chained.

Hope this helps, and I'll keep looking around for some additional info on this subject.

Mark