Ups does not sustain server 1

[Mahmoodmoosa]

Hi
I have recently bought several ups units, the largest was
Powercom 1500VA
Part Number: KOF-1500AP

I tried it for my server, but while UPS fully charged, when I run a test or disconnect the UPS power from the wall, the server shuts down immediately, the UPS does not sustain it as it is supposed to. I tested how much the server normally draws, using an ammeter, found it draws around 140-160 watt only, so the UPS should carry it easily.

I have tried this unit with other computers and devices, and it worked fine. I tried other UPS units from other manufacturers, and they all similarly worked with other computers, but failed with the server. I suspect the problem is likely to be the power supply of the server. The server is custom made. Its power supply is from HP, Product number is DPS-750RB A REV00F. I wonder if you heard about a similar problem before. Thanks.

Mahmood

 

[cajuntank]

So you have a hot plug 750W HP power supply working in a "white box" server? That's interesting.

Well, you definetly have enough VA to cover the 750W load, but I of course would be suspectful of this power supply operating correctly outside a non HP server. I mean, we are not talking about your standard ATX power supply here.

 

[Mahmoodmoosa]

cajuntank
Thank you.
Through further investigation, I found out that HP and IBM servers are very sensitive to power interruption. Usual UPS on the market are of a standby type or interactive type (there is 2-4 millisecond transfer period before the battery delivers current when the utility current is out) which is not a problem for most computers and devices, but it may be a problem of servers like those of HP or IBM, which need an online (double conversion) type of UPS (with 0 millisecond transfer time), I have ordered one of these, and hopefully will try it soon. Thanks again