converting 60hz motor to 50 hz

[Roadking04]

I have a friend visiting from the UK that would like to buy a couple of woodworking tools from the US and use them in England when he returns. The HP on the table saw is 3HP and 2HP on the planer, both are 120/240 V 60Hz single phase. I'm trying to deside which is the best and lease expensive for him. I have thought of buying a new motor for each, rewinding the motors, or a using a transformer. Not being an electric engineer, I would like to get some advice on which is the best solution.

Thanks for your help.

 

[waross]

Buy new motors in the UK. Your friend may want to change the pulley ratios to maintain the speed.
Some single phase motors are rated 120/240 but most are rated 115/230 Volts. The rated voltages at 50 Hz will be 200 Volts and 192 Volts respectively. The horsepowers will be 2.5 Hp. and 1.7 Hp. respectively. It will be difficult to find a transformer of suitable voltage in the US. The transformer voltage will have to be derated. you would need something like 277V/36V. The starting capacitors values may have to be increased, but they are fairly forgiving.
The project is do-able, but the cheapest and easiest is to buy the correct motors in the UK.
yours

 

[stardelta]

Buying a machine in the USA, having it modified and transported over here will cost your friend way more than it needs to. Surely the easiest and cheapest answer is to buy a similar machine here in the UK that is designed to operate on our 1ph supply system from the word go. I forsee a couple of possible problems, it could be that the motors are made soley for the application i.e with threaded shafts or special mounting arrangements which would make replacement very difficult, not uncommon with woodworking machinery, and then you would have to go for a expensive rewind and voltage/frequency conversion. The motors in question may be a standard NEMA frame design but again 1ph motors of this type are both rare and hence very expensive here in the UK due to the lack of demand. You may be able to modify the machine to fit a standard European IEC frame motor but without careful examination its impossible to say with certainty if it could be done. Transformers are an option but again its cost as they would have to be specially made and then you have 2 items that can fail instead of 1.
First thing I would do is ask the maker of the machine if they can offer a 240v 50hz option direct from the factory and the shipping costs to the UK. They may even have a sales agent here in the UK. I am sorry to appear negative and not be able to offer any realistic suggestions but I cannot see an easy (or cheap) answer to your question.

 

[CJCPE]

You should also check to see if replacement and alternate types of blades are available in the UK.

 

[dpc]

This 50 Hz vs 60 Hz question has to be about the most common one on this forum. Can someone write up a FAQ that we can refer people to?

I agree with waross - buy new motors.

 

[ScottyUK]

Buy a couple of cheap (~£150) 240V 1[Φ] VFD's and set them up for 240V/60Hz fixed frequency operation. The gentle acceleration ramp will reduce wear & tear on the machine. You will probably still have £££ in pocket.

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I don't suffer from insanity. I enjoy it...

 

[itsmoked]

ScottyUK has a good idea there.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[ScottyUK]

Of course, my idea is a really bad one if the motor uses a capacitor start or has a centrifugal switch for induction start. That's the kind of mistake that happens when you are posting after a couple of glasses of scotch. Sorry gentlemen - I shall refrain in future!


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I don't suffer from insanity. I enjoy it...

 

[LionelHutz]

It's still a good idea Scotty. Just buy a 3-phase version. Then, do as you said using the VFD for frequency and 1-phase to 3-phase conversion.

 

[aolalde]

Woodworking tools have the motor integrared in a block construction. That means a custom made motor almost out of any dimensional standar. The speed reduction at 50 HZ could result in poor performance.
My recommendation; buy those tools in the UK, designed to work at 50HZ, 240 Volts, that is the most economic alternative with proper operational performance.

 

[waross]

The HP on the table saw is 3HP and 2HP on the planer

This type of machine at this horsepower often uses a standard motor with a belt drive.
respectfully