New UPS suggestion

Doesn't fit in a category? It does now.
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KPJL FM
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New UPS suggestion

Post by KPJL FM » Wed Oct 03, 2018 8:11 am

I have to replace an old UPS, 220v in, 120v out, about 6KVA.
Any suggestions? What to get, what to avoid?
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Re: New UPS suggestion

Post by PID_Stop » Thu Oct 04, 2018 8:37 am

We used to use a lot of Liebert (Emerson) GXT series UPSs in that size: 208 in, 120/208 out. They have held up quite well, and because they're "on-line" units, noise on the input doesn't make it through to the output. Also, there's no glitch on the output from a relay kicking the feed over to the inverter, because the load always runs from the inverter.

More recently we've bought Eaton 9PX series: we tend to get a better price on them, and our experience has been just as good.

I've gotten bitten by APC too many times over the years, both figuratively and literally: they have a nasty tendency to overcharge the batteries to the point where they swell, and you end up gashing your hands on raw sheet metal trying to pry them free. They might be better now that they're part of Schnieder, but the price has never motivated me to give them another try.

Jeff
Last edited by PID_Stop on Thu Oct 04, 2018 11:16 am, edited 1 time in total.

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Re: New UPS suggestion

Post by Nathaniel Steele » Thu Oct 04, 2018 9:34 am

I really Like STACO, the UNISTAR seriesis what I've mostly used. They are online as well. they do have a fan that I wouldn't call noisy, but I would warn you it Could be an issue if you don't think ahead about placement. I had no choice but to put one under the console desk, and while it didn't casue problems onair, it was the loudest thing in the studio (Aside from the Talent!) I have no experience with anything over 3KVA but they do make them.

I too am not a fan of APC, for pretty much the reason stated. That said I have a bunch of them on the sales dept computers and other places where you just aneed a little quiet box on a non mission critical computer.

Eaton and Leibert seems to be highly regarded as well. I did contract work for a company that used both extensively, no problems I was aware of, just the usual battery replacements, and as to be expected if there out at a poorly temp controlled site, the batts don't last as long as they should....

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Re: New UPS suggestion

Post by kkiddkkidd » Thu Oct 04, 2018 6:15 pm

I am watching this thread carefully.

I have been bitten by almost all of the consumer level UPS's at some point... Particularly in the area of "what happens when the UPS screws it's-self into the ground and then the power comes back on"... I had been getting very good service from a particular model of APC SmartUPS that even if ran completely dead would recover gracefully upon return of commercial power. AND then had to replace a couple of them. And found that the new units would just sit there dead until the power button was pressed after power returned. The model number was identical except for maybe being a "j" version but that may have been a total change in contract manufacturer.

I really don't have time to run each UPS thru a battery (no pun intended) of tests before deploying...
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Re: New UPS suggestion

Post by kcbooboo » Fri Oct 05, 2018 3:29 am

Some true on-line units are very picky about the incoming power quality, which to me makes no sense, as all the incoming power really has to do is charge the battery and provide DC for the always-running inverter. TrippLite in particular wouldn't run on a mechanically-governed generator at an AM station because the frequency wasn't exactly 60.0 Hz all the time. Such units will ignore the incoming power, run exclusively on battery until that discharges, then just shut off, providing no power to the loads. Not surprisingly, all the equipment connected to the UPS ran fine on the genset power.

Some standby units (APC) will let power glitches pass right through. Most equipment can tolerate a few of those, but some computers may shut down and not restart. Also a LOT of UPSes will shut off and stay off if a battery goes bad, especially during the self-test. Things go along fine until that self-test, then the unit shuts off with no apparent reason, and you're dead in the water. Timely battery replacement helps. I've found a 3 year lifetime to be reasonable.

Some sort of bypass relay would be recommended such that WHEN the UPS shuts down you can still power the equipment from the raw utility power. Any power, regardless of quality, is usually better than no power at all. There was an article in the WorkBench column of the September 27 2017 issue of RadioWorld about a UPS Bypass Relay but the major UPS mfgrs also can supply such a device for big bucks.

It is annoying that most if not all true on-line units have a noisy, continuously running fan. Even some stand-by units have a fan that runs when the utility power fails. Some are much quieter than others. If the UPS will be installed in a studio, fan noise may be an issue. Putting noisy UPSes into a separate room (such as where the servers are) and running power from there to the required loads would be an ideal solution.

Bob M.

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Re: New UPS suggestion

Post by KPJL FM » Fri Oct 05, 2018 7:06 am

Thanks, everyone. Turns out we had a Liebert 3KVA on the shelf at TOC, that should be enough to work for this application.
I agree with the APC units. Other than a super small model, I stay away from them.
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Re: New UPS suggestion

Post by NECRAT » Fri Oct 05, 2018 12:02 pm

kcbooboo wrote:
Fri Oct 05, 2018 3:29 am
Also a LOT of UPSes will shut off and stay off if a battery goes bad, especially during the self-test. Things go along fine until that self-test, then the unit shuts off with no apparent reason, and you're dead in the water. Timely battery replacement helps. I've found a 3 year lifetime to be reasonable.
And this will happen when you are 650 miles away from your transmitter like I was. Thank god I put the redundant supply on another UPS.
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Re: New UPS suggestion

Post by Nathaniel Steele » Fri Oct 05, 2018 2:00 pm

NECRAT wrote:
Fri Oct 05, 2018 12:02 pm
kcbooboo wrote:
Fri Oct 05, 2018 3:29 am
Also a LOT of UPSes will shut off and stay off if a battery goes bad, especially during the self-test. Things go along fine until that self-test, then the unit shuts off with no apparent reason, and you're dead in the water. Timely battery replacement helps. I've found a 3 year lifetime to be reasonable.
And this will happen when you are 650 miles away from your transmitter like I was. Thank god I put the redundant supply on another UPS.
IF you can get someone to approve the extra money, there are automatic switchover units you can put the ups as primary and utility as secondary, that way if the UPS quits while you still have utility power, it will switch to utility power. They cost almost as much as a good 2KVA UPS. I always try to put equipment with redundant power inputs on separate UPS's. I've never had one of those "whole Building" UPS's with redundant inverters and huge battery banks and all that, I'm sure theyr'e nice if you can get one.

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Re: New UPS suggestion

Post by dbuckley » Sun Oct 14, 2018 6:18 pm

kcbooboo wrote:
Fri Oct 05, 2018 3:29 am
Some true on-line units are very picky about the incoming power quality, which to me makes no sense, as all the incoming power really has to do is charge the battery and provide DC for the always-running inverter. TrippLite in particular wouldn't run on a mechanically-governed generator at an AM station because the frequency wasn't exactly 60.0 Hz all the time.
Its generally not the exact frequency, its frequency instability and rate of change of frequency that annoy UPS units.

There is a very good reason why they are like this.

The online UPS will run in phase sync with the incoming power. It does this because the UPS has very limited overload capability, so a number like 150% overload for one cycle is all they can do before shutting down. Because the UPS has no overload capability, then it can't clear a downstream fault as there is not enough fault current capability to operate the breaker.

So what happens is when a downstream fault happens the UPS switches back to street power, which does have fault clearing capability, so the downstream fault is cleared, and a few seconds later the UPS switches the output back to the inverter. With some UPS systems this switching back to street happens for a step-change of load too; a building I worked in once had a UPS for one elevator, and every time the elevator started the UPS would flip back to street power. I often wondered if it would work in a power cut.

Obviously a UPS can only switch between street and inverter if the two are in phase at their zero crossing points, so the inverter is phase locked to street power. If the street power is, in the opinion of the UPS, insufficiently stable, it will refuse to operate.

Some UPSs can be configured to avoid this behaviour, and UPSs that can take one frequency in and output another always fit this category, so 60Hz in, 50Hz out. The cost of this is no overload capability.

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Re: New UPS suggestion

Post by radio_guru » Tue Oct 23, 2018 3:38 pm

We bought Legacy UPS's. They're made by the same people who started BEST and continue to offer an updated version of their FERRUPS designs up through 20KVA single phase 208 or 240. I can't speak for whether these updated designs die when the battery fails like the earlier FEERUPS did however.

We've got two 14KVA units powering the entire studios (using A/B source power strips in each rack and studio for dual source power) since 2011 and nary a burp. But we are due for a battery swap in 2019. Not cheap ($4000...16-75A/hr batteries.)

RG

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