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RPS and multiple UPS units

 
Tim Porreca_1
Occasional Advisor

RPS and multiple UPS units

We have a variety of Proliant servers (DL360, DL380, etc...) All have RPS and we always put one power supply on one UPS and one on another. Each UPS is an APC Symmetra with a dedicated feed from the building. Last week we fried one UPS and it was suggested that ouw config was to blame. See quote below. This sounds false to me. Isn't our config how these are supposed to be used?

Thanks!
Tim

"Depending on the design of the server and its grounds, power usage and the UPS you could be putting the UPS's in parallel causing the UPS to fail. Most UPS's you can not put in parallel because unless they are synched 100% on AC output they will float and cause standing AC waves and feed back to each other."
4 REPLIES
Stephen Grimmer
Trusted Contributor

Re: RPS and multiple UPS units

I really don't know about this, but I could easily see without special electronics to be in parallel the ups's would fight each other continously.

Tim Porreca_1
Occasional Advisor

Re: RPS and multiple UPS units

Really. That just seems really strange to me and would seem to negate much of the benefit of the RPS. The documentation says to plug them into separate circuits, but if those circuits cannot be protected by a UPS, what is the point? So you think you either protect against power failure OR protect against power supply failure, but not both.
You might be right, it just seems that this would be made more clear and I cannot believe I am the only one doing this.
Stephen Grimmer
Trusted Contributor

Re: RPS and multiple UPS units

Let's backup... I think its totally fine for redundant power supplies to be supplied by 2 different ups's that are on different circuits... I assumed the quote you noted is talking about putting the AC outputs from the UPS's in parallel.

Tim Porreca_1
Occasional Advisor

Re: RPS and multiple UPS units

Stephen,

Thanks. I agree and so does APC, but HP said that you cannot. Now it is clear as mud.

Tim