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# Changing a motor voltage from 460 to 220

## Changing a motor voltage from 460 to 220

(OP)
Hi everyone,

If any one can help with the right method to change a pump motor from 460v to 220v. I will attach the connection plan of the motor.

I wish that you can help me with this urgent issue.

Thanks.

### RE: Changing a motor voltage from 460 to 220

You can't.

You can obtain a 1.73:1 voltage change by going from star to delta wound, so a 460V star-connected machine could operate equally well on 266V if connected in delta, or a 460V delta-connected machine could operate equally well on 796V if connected in star.

### RE: Changing a motor voltage from 460 to 220

(OP)
Thanks a lot Scotty I would rather replace these motors.

### RE: Changing a motor voltage from 460 to 220

A connection that I have used and seen used many times is the auto transformer boost or buck.
In this case a boost.
If you can source a pair of 230:36 Volt transformers yu can boost your 230 Volts up to 266 Volts.
The current rating of the 36 Volt winding must be equal to or greater than the rated current of the motor.

Bill
--------------------
"Why not the best?"
Jimmy Carter

### RE: Changing a motor voltage from 460 to 220

What does the motor nameplate actually say and what do you really have as far as your supply frequency? Because that is most likely a 400/230V 50Hz motor that COULD have been used at 460V 60Hz connected in Star. If so, then as a 400/230V 50Hz motor, you can connect it in Delta and run it at 230V 50Hz just fine.

Don't worry about the 220/230V issues, those are just nominal values, motor typically are designed for +-10% to accommodate those variances.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

### RE: Changing a motor voltage from 460 to 220

European motors typically use three windings. The windings are connected in delta for the lower voltage and in star for the higher voltage. The ratio between the two voltages is 1.73:1.
North American motors typically use six windings.
The windings are connected in parallel for low the lower voltage and in series for the higher voltage. The ratio between the two voltages is 2:1.
From 266 Volts nominal to 230 Volts is about 15% low. Torque will be down about 25%

A common 50Hz rating is 230V:400V. The optimum 60 Hz voltages are 276V:480V. The speed will increase by a factor of 20%. The speed increase may make the motor unsuitable for pump applications.
But we are all just guessing.
What are the motor voltage and frequency ratings and what supply voltage and frequency are available?

Bill
--------------------
"Why not the best?"
Jimmy Carter

### RE: Changing a motor voltage from 460 to 220

(OP)
Good day all,

First, I would like to thank all of you for your responses. I will attach the name plate so you may advise me if I can give it a try to turn it on 220v.

Thank you.

### RE: Changing a motor voltage from 460 to 220

It's a 400/690V connection. The motor cannot take the rated load at 220V without rewinding.

Muthu
www.edison.co.in

### RE: Changing a motor voltage from 460 to 220

Transformer.

Bill
--------------------
"Why not the best?"
Jimmy Carter

### RE: Changing a motor voltage from 460 to 220

In terms of cost, installation, maintenance, foot print and modes of failure,
Rewind>New motor>New Transformer.

Muthu
www.edison.co.in

### RE: Changing a motor voltage from 460 to 220

I would use a pair of 120:240/240:480, 5 KVA lighting transformers.
Connected as auto-transformers they will handle the required current and will work on either 480 Volt 60 Hz or on 400 Volt 50 Hz.

Bill
--------------------
"Why not the best?"
Jimmy Carter

### RE: Changing a motor voltage from 460 to 220

I haven't been in a position to make a decision as to rewind or replace for quite a few years now. Back then the high North American labour rates made it cheaper to replace 10 HP or less.
Does anyone have a current figure for North American rewind prices?

Bill
--------------------
"Why not the best?"
Jimmy Carter

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