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How to run 50hz 220 volt German electrical appliances on a 60hz 110 volt system in USA.
: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: Savage93 ® 02/12/2010, 09:35:29 Author Profile eMail author Edit

I would really like to get information on how I can use my electrical appliances that I brought with me from Germany to the USA. I know that I can install 220 volt electrical wiring in my house and connect it to the electrical outlets I brought from Germany to install in my house here in the USA, but what I don't know is how can I change the cycles from 60 hz to 50 hz so that the appliances run as intended and the life span is not shortened by using 60 hz power cycle? Thanks for your replies. Rich

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Buck and Boost Transformer
: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: mcguigan3d ® 07/01/2008, 16:33:44 Author Profile eMail author Edit

Thanks to those who have contributed information above. I found that the product used for modest adjustments of AC voltage from line to load is a "buck and boost" transformer. SquareD make them: In my case I am taking a US spec bathroom fan to Jamaica which is 110v/50Hz . I figure I need to drop the voltage by about another 10V so I found a transformer that can be wired for 110/100 conversion . The transformer is wired as an autotransformer and not an isolation transformer so a 250VA rated unit can actually cope with a load 2kVA or more ( the 250VA must be for when it is wired as an isolation transformer ). Of course I had to increase to size of the fan I am buying to compensate for the derating due to lower AC frequency ( so I am getting a 300cfm fan as opposed to the 250cfm ). Grainger sell the product and my price was $135. They have models that will handle around 25kVA in the 120 volts vicinity and 35kVA or so in the 220 volts vicinity priced at $600. You can wire up three of them if you need to do a three phase conversion.

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Re: can i run 60hz motor in 50hz system
: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: Jraefield ® 07/27/2006, 16:32:22 Author Profile eMail author Edit

Using a 60Hz motor in 50Hz duty. 1) It will turn 20% slower. 2) Cooling will drop dramatically. 2) The load's horsepower requirements will drop, possibly dramatically. 4) V/f will increase possibly causing an overexcitation of the motor windings and an increase in current draw (see below). Make sure the load will still do what is required of it when running slower. For instance, a fan load would now move less air, a pump will pump less fluid etc. Still enough? The motor cooling will reduce dramatically. Is it enough to matter? This depends on how the load has decreased. If the hp requirement dropped because the load has decreased the current will drop and less heat will be released internally. You would want to take temperature measurements until the motor reaches a steady state temperature running in its new frequency application. The motor's hp will drop because hp is a function of speed x torque. The motor's torque doesn't change but its speed has dropped so it is now a lower hp motor. If you change pulley sizes to return the load to its original speed your motor will likely be undersized, possibly seriously. Example: A 10 hp motor is now an 8 hp. The most serious issue is the V/f issue. The V/f will increase. Likely enough to cause a large increase in the motor's current. This coupled with the reduced cooling may cause rapid overheating. However the V/f problem can be fully mitigated! You reduce the voltage to the motor by the amount required to return the V/f back to its original value. This removes the hazard of excess current from an increased V/f. Example: A 60Hz 460Vac motor is going into 50Hz service. V/f = 460/60 = 7.6 So if V/f x f = V then by plugging in the new frequency of 50 we see: 7.6 x 50 = V V = 380 Running the motor at 380V at 50Hz will remove the V/f problem.

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Re: can i run 60hz motor in 50hz system
: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: devitg ® 07/18/2006, 13:10:02 Author Profile eMail author Edit

Yes you can , air conditioning compressor motors often come rated at 60 Hz , and we run it in 50 Hz , of course it will run at slow speed , and the horsepover will be less too. It all depend what is the application.

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Re: Re: can i run 60hz motor in 50hz system
: Re: can i run 60hz motor in 50hz system -- devitg	Post Reply	Top of thread	Engineering Forum

Posted by: jam ® 07/19/2006, 06:49:43 Author Profile eMail author Edit

sir it was running in 24 hours service it is install at inlet cooler fan motor please write me now what effect in motor or its winding and its life

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Re: Re: Re: can i run 60hz motor in 50hz system
: Re: Re: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: randykimball ® 07/19/2006, 22:44:31 Author Profile eMail author Edit

The torque will be some less, the heat factor will be higher, the power usage will be less efficent, and the RPM will be effected. The RPM is dependent on the configuration of windings and the frequency of the phase Hz. This is how an electric clock keeps time, the motor is dependent on the 60 HZ. Convenient for a time system based on 60 increments, don't you think? This was no accident. Some motors, are less effected by the phase frequency than others. There are even some motors wound to run in either 50 or 60 Hz. However most modern effecient motors are wired and wound specificly for one or the other phase frequency. Motors with phase shifting devices in the primary circuit or designed to run on those circuits are of less concern. Motors like drill motors with variable speed circuits are less sensitive to various frequencies of input cycles. However, they are also an example of the fact that motors not wired and running at a chosen frequency are less efficent... notice how hot a household current powered variable speed hand drill gets when you apply a load for a few minutes. Your motor that is designed to run at a single speed should be run at the phase frequency it was designed for. However, if it is doing the job and isn't stalling nor getting hot, it COULD be ok for a long time.... Keep an eye on it! Watch to see that it doesn't get hot. (Even though it is out of its element) The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

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Re: Re: Re: Re: can i run 60hz motor in 50hz system
: Re: Re: Re: can i run 60hz motor in 50hz system -- randykimball	Post Reply	Top of thread	Engineering Forum

Posted by: shasim ® 08/06/2007, 23:47:53 Author Profile eMail author Edit

Can this be solved by using a Variable speed drive? I also have a similar application. If I install a VSD, will the motor be as efficent as with the 60 Hz system?

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Re: can i run 60hz motor in 50hz system
: can i run 60hz motor in 50hz system -- jam	Post Reply	Top of thread	Engineering Forum

Posted by: Kelly Bramble ® 07/18/2006, 09:25:41 Author Profile eMail author Edit

No, running any electric motor out of operating specifications is not a good idea.

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