# Industrial screw drive??



## Stephens4president (Oct 11, 2018)

OK I just bought an industrial air compressor on auction. I get it home and confirm that it's 3 phase. Kind of expected that and hoped that I could change to a large single phase motor. However the 3-phase motor is 25 hp. WTH? Does it really hake that many ponies to make air? What would happen if I replaced with a 5 hp single phase? Would it burn up out of the gate or just not make that much pressure? Any info will be appreciated and in answer to your question, Yes, sometimes it does hurt to be this stupid. Thanks


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## bigbob (Oct 3, 2017)

This is really not an answer, just some math.



Lets say the compressor made 100 PSI with it's 25HP Motor. 

A 5 HP motor would only be able to pump up to 20 PSI. It would be 1/5th of it's output.


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## Osviur (Sep 7, 2015)

Hi,

I think that this case would be better be solved by a mechanical engineer specialist in compressed air.

Just to take in account a very simple and easy to understand problem: Efficiency.

The mechanical efficiency of a 25 HP may be aprox. 90%. This means that 10% of the input power will be lost in friction and other losses. 10% of 25 HP = 2.5 HP used only to overcome the mechanical losses. If we use a 5 HP motor, half of this power will be used just to turn the pump. Transmission losses in the pulleys , belts etc, will reduce more the available power. Not to mention more complicated issues that convert this possibility in impracticable. Anyway, check if it is really a 25 HP compressor, see the brand and model to be sure what you have bought.
Good luck.


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