Help: Motor and frequency

[PH@NTOM]

Hello All.

If I have motor with frequency 50HZ, 415V and I want to operate it on frequency 60HZ, 415V



Or

If I have motor with frequency 60HZ, 415V and I want to operate it on frequency 50HZ, 415V

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What will be the effect of the motor?
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[Sintra]

The function of a electrical motor or transformer is dependent on the Hertz or cycles of the alternating voltage or current. This means that a motor or transformer would not function if the electrical voltage was not alternating.
Basically a motor or transformer is made by a manufacturer for a specific Hertz or cycles, so either for 50 or for 60 Hz.
This is mentioned on the nameplate of the equipment.
Sometimes it mentions both Hertz 50 and 60, but this is only for small (low wattage) motors and small transformers.
Larger motors or transformers are only made for a specific amount of Hertz, so either 50 or 60.​

What happens if you connect a 60 Hertz motor to a 50 Hertz mains:

The motor turns 17% slower

The internal current goes up by 17%
The power (watt) goes down with 17 %
The mechanical cooling is less, because of 17% less turns
The result is a higher current, then designed by the manufacturer and the insulation of the electrical wiring deteriorate much quicker, which after sometime results in a burn-out.​

 

[Darkwood]

If you use inverters which chop the frequency signal on a motor to control speed you can exceed its normal operating frequency in the setting to achieve a faster speed but the result is a loss of torque and go too high you can get a stall effect just like trying to set off in 5th gear in your car.

 

[PH@NTOM]

Nice answers

thanks mates a lot

 

[thepurple1]

If you are trying to get more duty out of the a motor ie fan or pump because its under sized then upping the hertz on the inverter is not the way the motor will not last long it will burn out. what ever you do get it in writing off the motor manufacturer

i done a job in January where the AHU fan motor was off its curve and they were not getting the duty. due to the fan being under sized (the consultant had F***ed up) The motor manufacturer advised the motors could do 55Hz this was still not good enough and eventually a figure of 74Hz was used. The motors did not last 6 months.