ATS /UPS Combination

[BillP]

I would like to know thoughts on an ATS / UPS combination that i think will solve a problem we have in smaller cabinet installations at one of our sites, let me explain...

So I have a site that has around 40 UPS's on-site.  We have had a times where a UPS has failed (SMX1500RMI2UNC) and stopped outputting power.  Unfortunately this is on a production line which we cannot afford to be down.  At the moment we have a SBP1500RMI installed but when we call site facilities and ask them to move the bypass over, they don't like to touch it because "Thats IT's responsibility".

So what I am thinking is an AP4421 for the smaller UPS's  4423's for the larger.  Then I use the output from the ATS to power either a SMX1500RMI2U or SMT2200RMI2U for the larger.  I then output the UPS power back into the second power input on the ATS?  That way if the UPS stops outputting power for any reason it will default back to the mains unprotected power, until we get the problem with the UPS resolved.  The UPS's have NMC's so we will be aware immediately that there is a problem.

The loads on these UPS's aren't large generally 1 or 2 Cisco switches with 715watt power supplies.

Is this possible? 

[Brad_C]

I have an AP7721 after an SUA3000. The UPS plugs into input A and a direct lead to the mains into input B. The PDU is on the output of the ATS.

If the UPS fails, it automatically switches over. I did it primarily so I could take the UPS out for service as I don't have a bypass panel but it also doubles to protect against UPS failure.

I can't quite get my head around your description as you seem to want to feed the output of the ATS into the UPS. I'd have thought you'd want that powering your load.

[BillP]

Thanks Brad

The problem I have is that I only have one power source nearby which is a 16amp commando.  Getting another commando at that location is difficult.  The cabs are in a warehouse location.  

So your last sentence is correct really.  Input A is fed from the 16amp commando, the output of the ATS then feeds the UPS, the output from the UPS then feeds Input B.  So in the event of a power loss from input A, power will be supplied by the UPS on input B.  In the event of a UPS failure which would feed input B it would switch to input A with no drop of power.

It's a bit convoluted... but it's the only way i see working with only one power supply nearby.

[Brad_C · Accepted solution]

You are asking the ATS to supply the UPS and the UPS to supply the ATS input B. So when the mains fails (Input A) the UPS will be supplying its own input. I don't think that's going to do what you think it's going to do.

In fact, I suspect it'll be a pretty neat oscillator as the UPS jumps back and forward off battery. Next time I'm playing around I must try that and see what happens.

[BillP]

Ah yes of course it will... Didn't think of that!  I knew it sounded dodgy when I thought of it, I just couldn't work out why at the time.  Thanks Brad!

I have just thought of another solution though.  16amp Commando splitter cable so one to ATS, one to UPS then UPS to input B.  That should work. 

[BillP]

Hey Matt,

One thing to look out for is that ATSs only support online UPSs but the two models you mentioned above are line interactive UPS.

The ATS may be damaged if used with a line interactive model due to switch thrashing at fail over. 

-Gavan