topic Re: UPS in Servers - General

UPS

Kuan Hau_1 — Mon, 14 Feb 2005 11:56:15 GMT

Ok here's a question which I have received mixed answers on and hopefully someone can clear this up:

Can you run a UPS in serial (so UPS A is only connected to UPS B, then from UPS B all the equipment is powered from there)? (i.e. mains-UPS{A}-UPS{B}-SeveralServers)

I heard that if you ran them in parallel there is a chance that you could cause cross phasing if the two UPS's ever connect...

Re: UPS

Raj_75 — Wed, 13 Jul 2005 11:43:57 GMT

Yes, you can connect UPS serialy. But UPS-A should provide sine wave out put. Otherwise UPS-B may go to the battery power.

Re: UPS

Mahesh Kumar Malik — Sun, 17 Jul 2005 05:51:57 GMT

Hi Kuan

Connecting UPS serially is not a standard practise. They should be connected in parallel with proper sync. In parallel they will do the load balancing and in the event of one UPS failure, other one can ccontinue to supply power. However, the assumption is that UPS capacities have been designed based on full load support on single UPS.

Regards
Mahesh

Re: UPS

Kuan Hau_1 — Thu, 21 Jul 2005 03:46:42 GMT

Thanks for the advice guys.

UPS A and UPS B have different KVA ratings. If they were run in serial then one could end up feeding the other. But if run in parallel would this cause an issue?

Thanks,
Kuan