Motors 50Hz/60Hz

[Barry Daly]

Hi All,

Having lived in the US now for 8 (great) years my wife and I have decided to move our family back to Ireland where we are both originally from. I have a question about bringing tools back there with me. What I am worried about is the Voltage/Frequency of the electrical supply. Ireland is a 220V/50Hz country. So my question is will my larger machines which are 220V/60Hz work over there. I have read that it may be o.k for universal motors to run using a 220 to 110 transformer but induction motors may not start at all or burn out.
I would really appreciate some input on this problem. I can't imagine having to sell all my tools and start again.
Regards,
Barry

[John Ricci]

Barry, all of your 240v tools should run on 220v 50hz but will not be quite as efficient. Expect slightly slower speed and a bit more current draw/heat but it should be nothing drastic. That is my particular understanding of the situation which should never be taken as gospel:D.

J.R.

[Greg Cole]

220V is 220V 50hz is 10 hz or cycles less than 60hz or you lose 20% of your output rpm's. The pulley on a machine with v-belts can be changed if needed where needed. I would look with a close eye on the motor tags, if you are lucky you will see 50/60 for hZ rating, which should alleviate the worry about the hZ anyway... so if you have 110/220 rated voltage motors, you are good to go. If have MY luck, you will be tool shopping upon relocation..... wish you better luck than tails me around.
The smoke is let out of an "American" device usually from putting 220V into something made for 110.... poof the smoke comes out.
I think IRE is 220 for residential & 380 for the higher voltages, but it's been a couple years since I installed some machinery in Charleyville, County Cork.

Best of luck.

[Rod Sheridan]

Hi, running a 60 hertz motor on 50 hertz certainly does result in reduced speed, as well as a burnt out motor if the applied line voltage isn't reduced proportionally.

Another problem is that single phase motors use a centrifugal switch to disconnect the starting winding once the motor reaches approximately 75% of rated speed. Running a 60 hertz motor at 50 hertz is 80% of rated speed. If your starting switch doesn't open, your motor will run with the starting winding energized. This will burn out the motor also.

An induction motor running at rated frequency will run at rated speed. At rated speed the motor generates a reverse voltage (Counter Electro-Motive Force or CEMF) that opposes the applied voltage to limit motor current. As the motor slows down, the CEMF goes down, the motor draws more current, this is what allows the motor to draw only the amount of current to run at any given load.

As can be seen, if the motor speed is low, the CEMF is low and the motor will draw excessive current (remember it's speed is frequency dependent).

I guess the short answer is, expect to replace all 60 Hertz rated magnetic componenets (motors, transformers, contactors ) unless they are rated for 50 Hertz.

Changing voltage is easy (Transformer) changing frequency would require a frequency converter.

Regards, Rod.

Electrical Technologist.

[Ray Moser]

Rod nailed it. A 60 Hz motor that is not rated for 50/60 Hz may overheat if run on 50 Hz current. The back EMF or counter EMF goes up as frequency goes up and goes down with a decrease in frequency. The result, too much current flow and over heating.

[Barry Daly]

Thanks for all the info guys, that is what I had read. What a pain in the a$$. Oh well, I suppose I'll have to look at it as au upgrade opportunity.

Regards,

Barry

[Noel Hegan]

Thanks for all the info guys, that is what I had read. What a pain in the a$$. Oh well, I suppose I'll have to look at it as au upgrade opportunity.

Regards,

Barry

Barry, depending on what tools you have and the value you put on them I guess you've 3 choices -
Sell Stateside and buy new stuff in Ireland
Rip out the motors and sell them, buy 50Hz motors over here
Run them as there are and replace as and when you start smelling smoke

If we're talking good cast iron machinery I'd suggest going with option 2 or 3. You will have difficulty sourcing similar quality items in Ireland and if you do you'll pay in excess of twice or 3 times what you paid for them in the States. Personally I'd go for option 3 or maybe even source 50Hz motors before you leave. As I mentioned, really depends on what tools you have and how you value them. I'd also suggest stocking up on consumerables before moving, you'll save a fortune as well as having a stock of stuff you'll simply not be able to get anywhere this side of the pond.
If I can be of any help please drop me a PM.