UPS DaisyChain

[Greglsh]

Hi

We have a client who has a shop, His shop has a 3kva online UPS system which is setup to run the most important equipment, tills, scales, backoffice pc, internet, switches ect. He has a generator which they have to start manually when they have power failure (load Shedding), which then puts power back into the ups.

What we want to do is add another online 2kva ups into the office, this will run the backoffice pc and the internet and they have a payment gateway pc for their credit card payments. The reason we want to do this is that we want to add an snmp device to this ups and then control the 2 pc's from this so that if for some reason the ups starts to go flat it will gracefully shutdown the 2pc's.

Long story but this is what I want to ask, will it be okay if the "new" 2kva online ups is plugged into one of the plugs that is supplied by the other ups and generator. We are not looking for any longer time just that this is basically the only plugs we can use to get the generator to charge the new ups. What are the problems with this setup?

 

[Drake2007]

Daisy chaining will likely not work unless the 3kva UPS is supplying clean power and not square sine wave which will look like bad power to the 2kva. Plus it will void your warranty.

I would get an electrician involved to sort out the generator - should be on auto, and to run a
new plug point to the new UPS.

 

[HavocXphere]

Rather run them side by side - i.e. add a multiplug to the genie then jam both UPS into the multiplug and split the device load over the two UPSs.

Daisy chain sounds like bad news to me & possibly unpredictable.

 

[Greglsh]

Thanks , I also Think that maybe each should have its own supply, wanted to see what others think. Thanks

 

[mogwaai]

Daisy chaining 2 modified Sine Wave UPS'a is not a good idea. Rather increase battery pack of 1st UPS or plug 2nd UPS in genset directly.

 

[dillinger]

You can do it but must put in a isolation transformer between the ups's or the one receving power from the other ups will burn out.

Make sure that the gen can handle both ups's as the starting current might be to much for the gen and the sign wave colapses for a fraction of a second and the ups wont sync with the gen.

 

[CriticalConsumer]

Agree with all the responses above.

 

[The_Unbeliever]

How big is the genset? If it's a 6kVa unit, then it should handle both UPS'es fine.

If the generator is a self-starting unit, then get a sparky to set things up so the generator will kick in automatically on power failure and give power to both UPS'es (the UPS'es will only be carrying the load for around 10 to 30 seconds until the genny starts).

This will be the safest way, not to mention convenience. All that need to be checked is fuel and oil levels.