UPS and pumps

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DHCrocks

Aquarium Advice Apprentice
Joined
Oct 27, 2008
Messages
12
Location
Hawaii
hi,

I tried pluging in my two penguin 660 power head and my Rena Filstar 3 filter into a APC XS900 900VA UPS battery backup and have a problem. The power heads run ok when I pull the plug to test the UPS, but the Rena doesn't work. It just makes a clicking sound. I tried to only run the Rena alone and still no go. I want to have a backup when the power goes out but the canister filter won't run. Anyone else have this problem?
 
The problem could be with the voltage output of the UPS and the design of the cannister pump. I've read that some pumps will only run with UPSs that give "true sine wave" voltage output. Most don't - they only approximate a sine wave curve with a stepped square wave. Not sure about your specific UPS.

With that said though... I run a UPS that does NOT use a true sine wave output, and have had no issues with any of my equipment: visitherm heaters, maxijets, mag3 pump, and a korallia. Guess it just depends on how the pump is designed.
 
That could be it, I looked up the specs and it said it was a stepped sine. I guess I'll need a different UPS. So strange that it is good enough to run sensitive electronic computers but not good enough to run a simple mechanical device.
 
That doesn't make sense to me. I work with a lot of pumps in my military job and I can't think of a motor design that wouldn't allow a step sine wave too work. Can anyone elaborate on the problem?
 
I did some Googling to find a good answer, but didn't really come up with any. I found plenty of other mentions on other forums that square wave, and some stepped wave forms don't work with SOME pumps, but no real good reason why. I'm no electrician, but I know that permanent magnet motors are designed to work with a sine wave input, so it makes sense that if you stray too far from that, it may not work. I'd assume that rather than it not working, it'd probably just sit there and hammer back and forth - constantly reversing directions.

Glad I could impress you CaptainAhab! Only reason I remembered that is because I did a lot of research before buying a UPS for my tank setup. I finally decided "What the heck... if it doesn't work, it doesn't work" and bought a non-sine wave unit because I didn't want to spend an arm and a leg. Like I said though, all my equipment seems to work fine with it.
 
Hammering back and forth is possible, but you'd have to be awfully far from the sine wave you're intending to imitate to stall such a small pump.

I assume you've tried the Rena with wall current and it works?
 
yeah plugged directly into the wall it works, plugged into the UPS with it plugged into the wall it works, but pull the plug to the UPS to simulate a power outage and it doesn't work, just makes a clicking noise, I guess it's that hammering back and forth thing.
 
UPDATE I just got this from APC:

APC's Back-UPS line is designed for use with Computer-type loads only. They are not designed to be used with motor loads such as fish filters, air conditioning units, space heaters, vacuum cleaners or any other machinery.

One potential issue is the inrush current draw for a motor. It can easily overload a Back-Ups UPS model. Secondly, these models of UPSs output a Stepped-Approximated sine wave when on battery. This waveshape, while ideal for computer-type equipment, is not particularly compatible with most motor loads. The result may be that motors run very slowly, erratically, or not at all when the UPS is on battery.

To protect this type of equipment, APC recommends first determining the appropriate size UPS for the motor load in question. Ensure that the Volt Amp rating of the UPS is sufficient to handle the start-up inrush current draw of the motor. Secondly, select a UPS which outputs a Pure Sine Wave when on battery, such as a Smart-UPS (minimum of a SUA700), Matrix-UPS, or Symmetra Power Array.
 
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