Can you run a 220 Volt 50 Hz split phase electric motor from the US on a single phase UK mains supply?

Answer 1

The mains frequency in Europe and other 230 Volt areas is 50 Hz (Cycles per second) compared to 60 Hz in US, Canada and other 120/240 Volt areas. Some 60 Hz appliances will work fine but others with simple motors will run too slow on the lower frequency of 50 Hz.

However the most important difference is in the way that the Neutral wire is connected in appliances designed to run on 240 Volt 60 Hz supplies: in addition to a safety "Ground" conductor there are 3 wires, a Neutral wired as a "central" common return conductor and two 120 Volt 60 Hz live "hot legs" which are wired in opposing phase to one another. When one hot leg is "+" (120 Volts positive) the other leg is "-" (120 Volts negative).

In 240 Volts 50 Hz appliances there are only 3 wires altogether, a "Ground" conductor, one single 240 volt "live" or "hot" wire and a Neutral wire connected as a return to the single "hot". So there is a 230 Volt voltage difference between the "Neutral" and the "Hot" conductor in the 50 Hz system and only a 120 Volt voltage difference between the "Neutral" and either of the "Hot"conductors in the 60 Hz system. At the point where the "Neutral" gets connected to the "Ground" (never in the appliance itself but at the point where the incoming supply enters the main fuse/breaker panel) - this difference will cause serious problems! That is why an appliance designed to be connected onto the 60 Hz system cannot be used safely on the 50 Hz system without first having proper technical modification work done. A licensed electrician or electrical engineer would be able to consider whether or not a particular large appliance, that was manufactured to work on 60 Hz-only, could be modified safely to run at the lower 50 Hz frequency. However it won't usually be worth the expense of doing the work because it would be more cost-effective to buy (new or secondhand) an equivalent large appliance designed to work on 50 Hz. Further information which may be useful to mention here but is not part of the answer to this question: Some 120 Volt appliances, such as electric shavers, etc., have been designed to run safely on different supply voltages and frequencies. If that is so, it would be stated on their rating plates. In many cases, where the power needed is low, such as (say) less than 30 Watts, a cheap and simple "International Travel Socket Adapter" is all that is needed to make such a 120 Volt appliance plug-in and work. Many international airports have shops selling such adaptors.

Answer 2

Sort of. Single phase power is available on any three phase system by using only two of the three wires. So using, say phase A and Phase B, you would have a 380v, 1 phase power source. To convert the 380v to 230v, you would need to use a transformer with the proper turns ratio (in this case 1:0.6) and sufficient power rating for the motor in question. You would also need to make sure both the motor and power source has the same frequency, like 60Hz. It is usually more cost effective to just replace the motor with one of the proper ratings, but it can be done.

Answer

Yes. But there is no need for a transformer if you are referring to a European 400/230-V three-phase system.

The actual line voltage of a three-phase supply with a nominal line voltage of 400 V, is allowed to vary by (+10/-6%), so it can be as low as 376 V. This means that a single-phase motor with a nominal voltage of 230 V will operate perfectly normally when connected between the line and neutral of a star (wye) connected 400-V three-phase system.

Answer 3

Yes it can be done. If the motor is US/CA manufactured and the voltage stamped on the plate says 220 volts. Then it can be connected to the UK supply, The only thing that you will find is that it will run marginly slower due to the mains frequency in the UK being 50 hz, and in the US/CA it is 60 hz. Normally 60 hz will run at a speed close to 3600rpm and 50 hz will run close to 3000 rpm.

You may also find that this will cause the motor to run slightly hotter due to the reduction in frequency (16.6%) and cause a slight increase in current and in turn efficiency. You might want to consider running it through an invertor to maximise its efficiency. It depends on how long you intend to run it for.

I have used machines made in the US/CA that are designed for 60 hz and run ok on 50 hz with no problems exept they feel warmer to the touch.

Most motors made within the last 10 years or so, will be designed for international use and will have different tappings for voltages and frequencies and are normally illustrated inside the terminal cover.

Is this for some machine that you have bought in the US/CA? price up an invertor against replacing the motor with a 50hz model. If you have any problems running it.

Answer 4

To be safe just use an appropriate transformer for that.