Urgent: Need a UPS

[Oops_my_bad]

Hi All

Can anyone suggest a decent rack in-line mounted UPS? looking to power around a dozen servers. Runtime about 20 minutes.

[DMcCoy]

I suggest you get a rough idea of the load of the 12 servers first, I think 12 for 20 mins is rather ambitious!

It might manage 12 for 4 minutes , but you will probably need a couple of bigger ups. Try looking at the apc RM5000

[torledo]

I suggest you get a rough idea of the load of the 12 servers first, I think 12 for 20 mins is rather ambitious!

It might manage 12 for 4 minutes , but you will probably need a couple of bigger ups. Try looking at the apc RM5000

The RM5000 suggested by DMcCoy is EoL.....The APC RT 5000 is the current equivalent product. Use the APC calculator to work out the load of the servers you need to connect....He's a very rough and ready calculation - you're servers will only use a fraction of the power they're rated for. But you'll need to calculate for the full load - so if an average 1 or 2U server is rated for 400W for 12 servers thats 4800 W, you'll then need to convert that figure to VA so that's around 6000 VA which is more, on paper, than the RT5000....but the RT5000 will be able to power that load with ease because each piece of equipment isn't drawing anywhere near the full power rating during normal usage - but the reason to budget for the full amount is the in-rush on equipment power on and also consider future expanison.

A 5-6000 VA ups like the apc model or equivalent mge, emerson or Eaton unit should be sufficient. One or two additional cascaded batteries will be needed to meet that 20 mins time you're looking for. Any UPS over 3KvA will also typically have a wired-in input connection. Above 5KvA you should be considering three-phase input. Up to 5KvA single phase is adequate. Also think about redundancy if you've got a lot of dual ps servers. 2N+1 (or is that 2N, i can never remember) means two UPS's to provide reduancy. N+1 is the more economical option as you're only need a single UPS - but you'll need a beefy UPS to do N+1.

Either way i'd budget 3 to 4 thousand including external batteries.

[ICT_GUY]

Thats going to be a nice job lifting it into your rack, 160lbs - 300lbs+

Remember not to lift with your knees and to use a sharp twisting movement.

[DMcCoy]

Not bought any servers for the last couple of years

Currently running 8 from a apc 5000, but I don't think it'll last more than 15 minutes with that load. Don't forget that you *need* your switches to be on backup power too as most of these solutions are going to need a managed network card (remember to get one with the apcs - one for each ups in fact). This will send the signal to the servers to shutdown when the power fails.

[torledo]

Thats going to be a nice job lifting it into your rack, 160lbs - 300lbs+

Remember not to lift with your knees and to use a sharp twisting movement.

i'd recommend taking the batteries out before you fit any UPS into you're rack!!!! - always have you're ups toward the bottom of the rack - what do you mean you haven't left at least 12U's of space in the bottom half of the rack for the real heavy stuff like you're UPS's and storage array's...., and always get a friend with anything bigger than a 2U server, although i'm sure there are some cheap and nasty ups's that don't have proper modular internal batteries....in which case good luck and yes, bend them knees

[Andrew_C]

- so if an average 1 or 2U server is rated for 400W for 12 servers thats 4800Kw, you'll then need to convert that figure to KVa so that's around 6000KvA which is more, on paper,

Err... 12x400=4800W. Which is 1/1000 of 4800kW.

[Oops_my_bad]

Thanks guys - I think I was a bit over-optomistic about the 20minute run time, 5 minutes seems do able

What is the difference between single and 3 phase? AFAIK at the moment the present UPS is a single-phase model (5000VA) but has a great big wire going into it from the wall with one of those big outdoor-stylee connectors

[torledo]

Err... 12x400=4800W. Which is 1/1000 of 4800kW.

ooops!! One of those things where what i was thinking was not translated into the correct math. Corrected the mistakes in original post, thanks for you're eagle-eyedness..

[torledo]

Thanks guys - I think I was a bit over-optomistic about the 20minute run time, 5 minutes seems do able

What is the difference between single and 3 phase? AFAIK at the moment the present UPS is a single-phase model (5000VA) but has a great big wire going into it from the wall with one of those big outdoor-stylee connectors

Sounds like you're current UPS input is connected to an IEC 309 socket, sometime knows as 'commando' plug and socket. This is one way of providing a 'hard-wired' connection with an element of portability. Not sure if this is suitable for hard-wired ups as it's not strictly hard wired is it ? But then i suppose it might be a valid configuration for a single phase system - maybe someone can clarify the electrical regs, if any, of wiring the input side of a hard-wire UPS.

Using a commando socket i think wouldn't be appropriate for a UPS requiring a 3-phase hardwire input.

[john]

I would say that connector would be valid, and you could probably do a 3 phase one that way to a point as well, but I will stress im not an Electrician.

As for the unit itself, Liebert I've had good success with as well as MGE (who now own APC)