power conditioning

May 28, 2006 12 Replies

This is probably an old question, but here it goes again.



I have recently bought a generator for emergency use. I want to occasionally use it to power the tv and/or computer equipment. I have read numerous posts that state some generators operate electronic equipment ok and many that say it fried the electronics. So here's the question: What type of power conditioning is best for interfacing the generator power to electronics? UPS? Inverter? Other?



Enuf



The best way to run your electronics on backup power is with DC, using the generator to charge the batteries. High-reliability Telco and network equipment is powered by 48 volt inverters.

Most smaller UPS's don't work well on power from small generators. The voltage and frequency will both be too unstable. They'll keep switching back and forth between line voltage and inverter.

So if you're runn> This is probably an old question, but here it goes again.

OK, inverters come with outputs in true sine wave and modified sine wave, with the modified wave units being more common and cheaper. Will tv's & computers work ok with modified sine wave inverters?

Enuf

Actually, the cheapest and the most common inverters have square-wave-output.

Yes.

I wonder about the initial assumption that a small generator is unsafe for TV/PC. Isn't the generator's output pretty close to a perfect sine wave - better than what comes out of a UPS? The frequency may go up and down a bit - I don't think this is a big problem unless you are using a turntable. Voltage will waiver but if you don't overload the generator this might not be too bad.

If you wish to use a UPS w. the generator, be sure to buy one that has a sensitivity switch to ignore generator variations.

Mike Berger wrote:

They're unsafe in that the voltage and frequency can fluctuate wildly especially as the load changes. I'm sure some consumer electronics devices will handle it fine, but most of it isn't designed with wide operating margins these days.

Bennett Price wrote:

No. Take a look at the output with a scope and you'll see.

My sig file can beat up your sig file!

Any idea why it isn't a sine wave?

bud--

It would take way too much typing. Find a college EE book on power generation and distribution, then prepare for some heavy reading.

In layman's terms, its the transformers and motors that help clean up the power on the grid and you don't have all that to help filter the output on a single small generator.

My sig file can beat up your sig file!

I stand corrected about suitability of small generator for TV/PC. I found the following APC FAQ's very helpful. Also addresses waveform of small generators (with non-linear loads).

Bud-- wrote:

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