Can I use an APC UPS for DVDR and clock radios?

Hi!

That is likely to be a phenomenally BAD idea. APC may only say that for liability concerns, but there may be some very real safety and performance issues to keep in mind.

For the Philips DVDR, *perhaps*. It's likely to use a switchmode power supply same as a computer, and therefore it won't care too much.

The output of a cheap UPS such as this one is NASTY. It's usually a squarewave or "stepped approximation to a sinewave". These low end APC UPS units are the epitome of cheap UPS design. I do not know how they do as well as they do.

There are two problems with the clock radios. First, practically every one I have seen uses the powerline as a timing reference. If this reference goes away (and they switch to an installed 9V backup battery), it appears that the microcontroller keeps time based on an internal timing loop. And from the looks of it, the stability of that loop is pretty bad.

With a UPS providing the input, the timekeeping may go all over the place.

There is another, more sinister problem, however. As your clock radios are likely to be powered by a cheap transformer, that transformer may very well overheat and burn out when running from a UPS that doesn't output a true sine wave.

William

That's correct. It doesn't take much to create a ground loop with your body in the circuit. The life you save may be your own. The standard solution is to ground everything, which does not mean digging a hole and burying everything in it. Fortunately, the APC Back-UPS

300 has a "site fault indicator", which will give you something to think about as you bounce off the walls.

Count Dracula did it better with just a coffin full of Transylvanian dirt. No need for all that expensive technology.

Yep. The only problem is that the Back-UPS series produces an ugly modified sine wave, which means that the output waveform looks only vaguely like a sine wave. That means you have lots of energy in the harmonics of 60Hz. (A square wave has 1/3 of it's power in harmonics). That won't cause too much trouble unless you have a badly designed input filter, that turns these harmonics into heat. Transformers also don't like harmonics. The easiest way is to try it. If your equipment catches fire, it won't work.

That's normal. Older equipment tends to contract Alzheimers and forget things. At this time, there's no cure, but I suspect you're on the right track. A UPS should help with whatever problem you're trying to solve that I already forgot.

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Can't see why not, they don't want the liability that medical equipment carries.

In fact, I've got my iron lung hooked up to

a

computer UPS

But it

has

shutdown...

They're cheap and they work. I've used APC * products for years, and never had problems. The power goes out, and within milliseconds the SPS (it's not a UPS) has taken over.

• APC also stands for aspirin-phenacetin-caffeine. Anacin used to have this formulation, until it was discovered that pheacetin caused kidney damage.

Hi!

I never said that they didn't. I have several of them here, some on their second battery. For what they are, they work well. I could not complain about that.

And that's what I was getting at--they don't have any means by which to do a periodic self test (other than at power on), and the only way they can stabilize line voltage sags or surges is by going to battery. I had one that wore the battery out very quickly that way, and I didn't know until it actually failed to support the load.

Technically speaking you're right, but I'm going by what is on the box to keep it simple (at the cost of some correctness of course).

It's all in the context. I don't think you could expect much if you plugged a box of Anacin into a wall outlet.

:-)

William

I have my home kidney dialysis, hyperbaric chamber, and MRI scanner hooked up to APC battery backup units with no problem. Should be no problem with a heart-lung bypass machine which is a good thing to have if you want to perform open heart surgery on yourself at home.

Suture self.

This is not of a concern for you, or the equipment. They just don't want to be sued by your estate if the UPS should happen to be interrupted.

Sylvia.

LOL!

In article , William Sommerwerck writes

oh, *ouch* :)

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