What phase is this please

[James bell]

Hi people I'm new on here and my question is I've been giving an air compressor for free but not sure if it's a 3 phase or single phase so if I can post a pic of it can anyone help me and also I it's 3 phase how could I wire it up to use on single phase thanks

 

[James bell]

Hi people I'm new on here and my question is I've been giving an air compressor for free but not sure if it's a 3 phase or single phase so if I can post a pic of it can anyone help me and also I it's 3 phase how could I wire it up to use on single phase thanks

 

[Minder]

Nice 3phase motor and 10HP!
Not really a decent way to hook it up to 1phase.
Compressors normally run under a fairly high load.
You could try selling the motor and get a 1ph replacement.
M.
.

 

[James bell]

So do you reckon I just buy a single phase motor and swap the 3 phase for a single phase motor?? Thanks for the reply so quick

 

[Minder]

I see you are in UK so it would be easy to fit a 240v version.
I see it is a 2 pole motor which is unusual for a compressor.
This decides the RPM, the 4 pole version will be half the rpm.
M.

 

[James bell]

I see you are in UK so it would be easy to fit a 240v version.
I see it is a 2 pole motor which is unusual for a compressor.
This decides the RPM, the 4 pole version will be half the rpm.
M.

Thanks I didn't know wether it was 2 pole or 4 so thanks for pointing that out, yeah I'm in the uk

 

[Minder]

RPM= 50hz X 60sec/pairs of poles - slip freq.
50x60/1 = 3000-140 cycles = 2860 rpm.
M.

 

[duke37]

A single phase motor will be much bigger than a three phase motor, it needs to fit.
A single phase motor needs a starting circuit and a high current supply. In one case that I was asked about, there was too much voltage drop to get the compressor up to speed even though the cable was probably adequate to run the compressor once started.
10hp = 7460W
7460/240 = 31A
Correct for power factor, say 0.8. 31/0.8 = 39A

Several times this will be needed to start.

 

[Minder]

Thanks I didn't know wether it was 2 pole or 4 so thanks for pointing that out, yeah I'm in the uk

Sorry my math was wrong, as you see by the plate it is 3HP.
M.