# Current for 220v hp water pump

Discussion in 'General Electronics Chat' started by Juvi22, May 8, 2015.

1. ### Juvi22 Thread Starter New Member

May 8, 2015
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Good day everyone could I get some info Need to get a step up transformer from 220v to 110v for an half hp 220v pump wat would be the current

2. ### Dodgydave AAC Fanatic!

Jun 22, 2012
5,159
772
0.5hp is 373W, so @ 220V thats 1.7amps secondary side, primary side will be at least double that approx 3.5amps.

3. ### MikeML AAC Fanatic!

Oct 2, 2009
5,451
1,066
The problem with specifying a transformer for that pump is that the locked-rotor = instantaneous start current inrush is about 10X the running current, so the transformer must be able to supply ~30A for a couple of cycles of the AC waveform.

May 8, 2015
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Thanks a lot

5. ### pafitis New Member

May 8, 2015
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So one 1/2 hp at 22o volts its equal to 373W
Now use the formula Watts divided by Volts, hence 373W/22oV makes as 1.69Ampere

6. ### Juvi22 Thread Starter New Member

May 8, 2015
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0

Jan 15, 2015
1,055
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1 HP = 746 Watts that is a given. So logically 0.5 HP should be 1/2 of 746 Watts or 373 Watts. Now if someone could show me a motor with those numbers on the name plate that would be really cool. Never thought I would see a perfect motor in my lifetime. Most 1/2 HP motors I have seen draw considerably more, to deliver 0.5 HP many draw in excess of 0.5 KW.

Ron

8. ### JWHassler Member

Sep 25, 2013
204
34
Step up from 22V to 110V?
Also, are you sure that the motor cannot be re-connected for 110V operation? Lots of single-phase motors can be.