Hello. I have a 1/4 HP pump and I want to connect it to a UPS in case the currento in the house cuts off, I have 1 or 2 minutes to close a valve. I understand that if it is 1/4 hp it has around 200 watts. I know a induction motor has around 3 times the nominal power in the start, but since the UPS will be connected to the 220V socket there shoudn´t be any problem right? I mean, a 500watts UPS should be ok, right?

Thank you

Best regards

 

I would recommend at least a 1000-Watt UPS.
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I know a induction motor has around 3 times the nominal power in the start, but since the UPS will be connected to the 220V socket there shoudn´t be any problem right? I mean, a 500watts UPS should be ok, right?

In addition to recommending a 1.0 KW supply you may also want to take a look at your UPS waveform out. Lower cost UPS units output a MSW (Modified Sine Wave) output verse a TSW (True Sine Wave). Make sure your pump motor will run as normal with what you have.

Ron

 

I also agree that a 1kW UPS should be used

 

Thank you!

 

Something to keep in mind – uninterruptable power supplies are rated to provide VARs, not watts. A VAR is apparent power =

amps × volts × power factor.

Our furnace blower motor is rated at ¼ or ½ horsepower, so it should draw less than 343 watts. Yet it almost maxes out our 1000 VAR rated ups because it has a crappy power factor. The current draw on our 24 volt battery system is around 40 amps.

The system that seemed like with would allow us to run the furnace for many hours during a power failure is more like "run the furnace for short periods to keep the chill off."

 

Tanks for you answer. Yes, I only need to provide the running pump for less than 20 seconds, The time to closse a valve, but I want to know if it could run it for that 20 seconds, so i´ll go for a big UPS

 

There are two parameters that are important with a UPS. The first is the V×A rating I talked about above. This is the maximum amount of power that can be delivered to a load.

The second is the amp-hour or watt-hour rating of the UPS. This is the energy that can be delivered to load.

Let's say your UPS is rated for 500 watt-hours. Plug in a 100 watt light bulb, and it can run for 5 hours. Plug in a 1000 watt toast, and the UPS will only be able to run it for half an hour.

This is where a lot of advertisements for "electric generators" that operate from car-batteries get deceptive. Yes, they may be rated at 2000 VAR, and they may power your refrigerator, coffee pot and TV at the same time, but they are cagey about how long they can do that.

 

Thank you