How to Find the Size of Magnetic Wire for a Motor

It was a specially design Motor. The Outer frame was different.

Also it will take more time for order, then back to fixing. Till that Plant will not wait.

Still order a new motor, and the project timetable is wrong.

It will take much more time to build the coil winding jigs and for us to explain how to reverse engineer the magnetic design. If you cannot purchase a new motor, search for an electric motor rebuilder.

How about a Voltage transformer? 480 V in and 380 V out?

By saying that, what do you really need to achieve? Anything on the application and why it is not considered to use the correct motor for the application?

What did the vendor of the motor had to say about this?

It was comes with some other equipments ( Big Plant Machinery). Due to some issue they are changing the voltage of that machine. The Power for this motor was also passed in with its control Panel.

So need to change the design to adopt the new voltage.

That is the best quick and fully effective method, leaving the motor alone of course!!

Was it originally rated at 50Hz? Maybe you don't need to do anything.

No it was 60HZ. Here in Saudi Arabia

See :

Electric Motors from 12/20/2013

http://cr4.globalspec.com/thread/87611#newcomments

Buying a new motor is really the best solution. You should be able to sell the old motor and get back some of your money.

Rewinding the motor with a larger gauge wire and insulation in a space that is already full from the lower voltage application? Not likely to fit. Autotransformer or oversized line reactor? Have you studied the dangers of arc flash? Somebody messed up on the purchase of that equipment. Are you sure you want to take over the responsibility? The least expensive solution is to buy the right motor. The next best solution will be to invest in a good three phase transformer.

If you try to "adopt (to) the new voltage," you will be responsible for any failures. Sounds like a good way to lose your job! Some boss is trying to hide from this mistake! Convince him it was the original designers fault and move on!

Thank You So Much for your valuable words,

Ya, always the boss will hide behind while failure comes out.

Why do you think changing the wire size will do this? Since the voltage is going up the current will go down so the wire size doesn't need to change. It is unlikely that the insulation will care. If you're worried about the power that will depend on the mechanical load.

What you're up against is a Volts per Hertz problem. As designed the V/Hz is 380/60 = 6.33, the new one will be 480/60 = 8.0, that's over a 25% increase that will probably lead to saturating the iron and severely overheating the motor. What you need to look at is the number of turns and the saturation characteristics of the iron.

Unless that you're really skilled in motor design/rewinding, I suggest that you follow everyone else's advice and buy yourself an autotransformer, it will be a lot cheaper and quicker than trying to figure out how to rewind a special purpose motor (if the magnetic circuit will even allow you to do so). It's not a job for amateurs.

You got me! I had my thinking cap on backwards on wire size. Just to be clear, would it not be the case of needing both more turns (of the same size) and less iron? Looks like I going to have to review my motors book. I'm glad that I'm not dealing with this problem! So much to remember, so few brain cells left...

Thanks a Lot Boss,

This is what I expect.

Human life was full of Trail & error.

Pull it and send it out to a reputable motor rewinding shop for evaluation and conversion to 480V.

Unless you have the correct motor winding equipment and the knowledge to perform the motor rewind you odds of success are minimal.

VFD have gotten relatively inexpensive. Be cheaper the a new motor or having it rewound. Most have current limiting capabilities.

First of all, according to IEC 60038 the rated voltage of 380 V was tolerated up to 2003.

However, according to IEC 60034-1[Fig.12] a motor has to present unchanged properties up to 5% voltage raise and tolerable parameters in +/- 10% voltage change.

Then 400 V it is only 5% more and in "translation" from 50 Hz to 60 Hz 480 V is still ok [In my opinion].