"sw" wrote in
:

Do you think it's OK for a square wave inverter to feed a UPS that
feeds a PC? I would really like to do that but was told by some one at
APC it's a no no. My feeling was he had no idea and was just covering
himself. Thanks



If you sold UPS products to make your living, would you want them to use
just any ol' cheap inverter....or your geewhiz technological wonder?

There aren't any "square wave inverters" left on the market that I know
of. Manufacturing inverters with sine wave synthesis is just too cheap
and easy now. I just bought a 750 watt sinewave Black & Decker from
WalMart for $70! It will even crank an 8000 Btu Samsung air conditioner
with its 1500 watt surge rating. It has three 30A fuses in parallel.
(No, you can't aircondition your boat on a boat battery....maybe a
submarine battery.) It doesn't even turn its fan on until the load gets
over 150 watts, it's so efficient. Driving my 1.6A fridge and a few
loads on my workbench, it hardly gets warm. The fan in the inverter
turns on and off as the fridge cycles...letting me know when the beer is
cold.

ALL of these little cheap inverters over the power input demand of the
laptop will run the laptop just fine and charge its battery. Mine
charges in the car from a 175W inverter that cost me $20 on sale. Your
PC is no exception, either. It also uses a switching power supply that
works perfectly with a very wide range of input voltages from DC to high
frequency AC. It matters not as the input is a rectifier feeding a big
storage capacitor the switchers use power from to create the output.
Everything is converted to SMOOTH DC at about 170VDC off the AC line,
whatever that line is. Many switching power supplies are rated from
90VAC to 270VAC input at any line frequency of whatever nation you happen
to plug it into, so the manufacturer can send any computer to any
customer, no matter where he/she lives.

AS a note, I'm using a large APC UPS to power the computers in my office.
It provides smooth power and automatically shuts down Windoze before the
battery goes dead if the power outage is elongated. That's the reason I
bought it, not for its perfectly-smooth, xtal-regulated 60 Hz at 120VAC.
There was an "electrical noise" that lasted 8 seconds the last time it
switched on to protect the equipment, probably caused by the beer fridge
or electric heater running off the same outlet its plugged into coming on
simultaneously...???

Larry
--
If the damned government isn't going to enforce
immigration laws, can they at LEAST park an ICE
paddy wagon in front of WalMart so I can find
a parking place and make the checkout line SHORTER?!