You see the number of revolutions that an electrical motor turns is dependent upon the cycles per second (Hertz) that the alternating current (AC) is changing. A motor that is designed to run on 60 Hz and is plugged into a 50 Hz power supply system will turn 17% slower, the internal current will go up 17%, the amount of power (watts) will go down 17%, and the appliance mechanical cooling will be 17% less. The end result will be that the motor will be using a higher current then what the motor was designed for, and this in turn will burn up the insulation of the electrical wiring which can result in burnout which could cause a fire because of the excessive heat.
An induction motor designed for 60 Hertz which is running from 50 Hertz power supply will draw more power and run hotter and slower. But this is unlikely to burn up the insulation and cause an outright fire unless the motor was designed poorly and running very hot on the proper frequency to begin with. Still, the consideration of smoke and fire is disturbing. The extra heat can be compensated for by using a fan or larger fan on the motor shaft to cool the motor.
Since output is proportional to torque and RPM the difference in output will be 1/6th less if a 60Hz equipment is changed to 50Hz. This occurs a lot with trailer mounted recap equipments. If the appliance has reduction gears (smaller frame gas turbines and aeroderivatives) then the gearing can be changed to keep the output from changing. Thus, larger frame gas turbines (i.e. no gearboxes) can't be swapped between countries with different frequencies, but equipment with reduction gears can be.
I've seen an entire plant relocated from 60Hz to 50Hz power system and some areas of the plant had significant problems due to the slower motor/pump speeds. Some equipment needed 50Hz to 60Hz converters to operate properly.
Aside from motors, in principle there is very little to choose between 50 Hz and 60 Hz. 50 Hz is slightly better for long distance power transmission because the power loss in the overhead lines is less. But a 50 Hz transformer needs about 17% more iron in it so it is are bigger and heavier.
When you use frequency converters for appliances, you'd better be careful in selection of the frequency converter.
Related article: Impact of 60Hz (50Hz) motor being used on 50Hz (60Hz) power supply
Comments
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wilson
Just Shifted to Philippines from Gulf - with most of my home appliances of 220 V - 50 Hz (Refrigerator - washing machine- microwave - cooking range etc.,
but here at Philippines the power is 220 v - 60 Hz
what should I do to run these appliances.
Guest
Please read the question next time.
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I have a Be&sco Betamax oven that runs on 60Hz and now i have relocated this oven to a country that has 50hz power.
I have read that there will be a loss of 17% speed and power while a decrease in fas speed which may result in over heating.
Please advise if i need to use some converter to push the power from 50Hz to 60Hz.?
On the other hand, i have an rotating over that you can check by name given above and it also comes with a Wedge press unit (Be&sco).
Kindly give me some thoughts, if possible.
Many thanks.
Jamal
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Fahad
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I want to run a motor with No torque loss @ 60 Hz using a VFD and a input power of 50 Hz, 380V. Is it possible and will it work?
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However, the mathematical model that requires that you must increase voltage as you increase frequency was used by the earlier VFDs and was based on the motor being purely inductive (which it is not) and was only used when the motor was operated at a frequency below its rating. These primitive VFDs were marketed as producing constant torque (constant current) below rated frequency and constant power (actually constant voltage) above rated frequency. If this model were applied in this case, the 50Hz motor would be running above rated frequency, so it would be supplied the same voltage at 60Hz as it was designed for at 50Hz.
Given that the voltage on the 60Hz system is probably 240V and the motor is rated at 220V it would probably operate acceptably if it were driving a load where the torque requirement decreased with speed. Unfortunately, like compressors running on closed systems have a roughly cubic relationship between speed and torque requirements, so this motor can be expected to fail prematurely.
Guest
BUT . . . I usually run it from 120V 60Hz supply. And that is good for most jobs.
But the torque is down. I only ran it from the 240V 60Hz occasionally when I did need the extra power.
Drilling one, 1" hole through 10" of steel reinforced concrete took me about 7 hours. :-( . . . . . Most of that time was to allow the Motor, yes, the Motor, not the outside case, to cool down between drilling sessions. The drill is still in working order.
I should have mentioned, do not run a 230V compressor motor from 120V. It will probably stall or fail to start, so could burn out the motor.
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What things I need to do - so that I can still use it to its maximize power?
Thanks!
Rodel S
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Justo
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GoHz.com
Eduardo