110 -220 Compressor Motor Wiring Question

[70 140]

First time poster, been lurking a while though - mostly in the gallery.

I bought a used IR T-30 compressor that has a 110/220 single phase motor on it. It is currently wired for 220. Long story short, I have 220 service in the garage, but need to do some serious re-wiring (mostly de-wiring all of the P.Os crazyness) before I hard wire anything in.

In the mean time I would like to run it on 110. I have the wiring diagram for the electric motor, but am confused by the writings in pen. I assume the manufacturer didn't do that?

Here are a few photos, can anyone help me with this?

So far I think white goes to the white (line) from the motor. I am confused about the rest of it though

Thanks!

 

[G_P]

Im taking a stab at this but I would wait for someone else to confirm.

Your black (hot) wire from the wall goes to terminal 1
Your white (neutral) wire from the wall goes to terminal 4 and the white wire with from inside the motor also goes to terminal 4
Move the brown wire from inside the motor to terminal 5 in place of the white wire that you moved to terminal 4.

How many HP is this motor? If its a big motor running it at 120v is going to require a dedicated circuit. Possibly a 30a circuit. IIRC my 3hp compressor motor would draw 21 or so amps if run at 120v.

 

[The Cobbler]

t-30 search brings up several compressors. it seems to be a large commercial comp with high amp motor. why can't you leave it wired to 220?

 

[G_P]

t-30 search brings up several compressors. it seems to be a large commercial comp with high amp motor. why can't you leave it wired to 220?

The smallest motor I can find hooked to a T30 type compressor is 5hp. Good luck if you plan on trying to run a 5hp motor at 120v.

 

[70 140]

Thanks for the info.

Its an older T30. I believe the motor is a 3hp, but I can double check that.

I will be running this off of a dedicated 20amp circuit until I get the re-wiring done.

 

[Norcal]

Thanks for the info.

Its an older T30. I believe the motor is a 3hp, but I can double check that.

I will be running this off of a dedicated 20amp circuit until I get the re-wiring done.

There is no way a 3HP motor will run on a 20A 120V circuit, even a 2HP is prone to tripping the circuit breaker when wired for 120 volts.

 

[Stuart in MN]

Can you post a photo of the ID plate on the motor itself? It should state the full load current ratings at both voltages.

 

[G_P]

There is no way a 3HP motor will run on a 20A 120V circuit, even a 2HP is prone to tripping the circuit breaker when wired for 120 volts.

Yeah. you will need a 30a dedicated circuit for that. If you have to run a new circuit anyways why not run a 240v circuit? This would allow you to use smaller gauge (meaning cheaper) wire.

 

[70 140]

I fooled around with it a little today. Decided to leave it at 220 and run it off the generator until the wiring gets re-done.