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Dears,

We received a 50 Hz 5.5KW 220V Motor, How to change this to operate in 60HZ.

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  • \$\begingroup\$ Ask the manufacturer. \$\endgroup\$ – Dave Tweed Feb 5 '17 at 12:47
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    \$\begingroup\$ Just ask to replace. Any solution will be pain in your neck. The working point is different enough to not work at all or to work poorly, so you would have to use inverter between your mains and the motor. \$\endgroup\$ – Gregory Kornblum Feb 5 '17 at 12:47
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    \$\begingroup\$ By the way, there was that old russian forum where people recommended ways to overclock PC CPU from 100MHz to 140MHz, mouse from wired to wireless, displays from 14" to 17", i think it's same idea with this motor. \$\endgroup\$ – Gregory Kornblum Feb 5 '17 at 12:49
  • \$\begingroup\$ if you change the number of pole ! yes you can \$\endgroup\$ – m salim Feb 5 '17 at 12:55
  • \$\begingroup\$ Running it directly on 220-ish V @60 Hz would probably work, but is not recommended. I guess most AC motors would run 20% faster, but the torque wouldn't necessarily be the same. If it's a universal motor (which can run on both AC and DC), it should work just fine at 220 V. // Using a too low voltage will also cause the motor to have less torque. If the motor stalls it can overheat. \$\endgroup\$ – Oskar Skog Feb 5 '17 at 12:58
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The motor will operate 20% faster with 60 Hz. The driven equipment may run properly at a faster speed and it may not. If the motor is driving a fan or a centrifugal pump, it will require 44% more torque and 73% more power. That would not work at all. If the driven equipment is something like a conveyer, it will require no more torque but 20% more power because power is torque multiplied by speed.

In order to produce the same torque at the higher frequency, the motor should have 20% higher voltage or 264 volts. If you try to run the motor on 220 volts, the torque capability will be reduced in proportion to the voltage squared. Since 220 is 0.83 X normal voltage the torque capability will be about 0.69 x normal torque. If you can run the motor at 240 volts, the torque will be 0.83 x normal. If you can boost the voltage to 264 volts with a transformer, the motor will work properly. It will produce normal torque and 20% more power. It will be ok for something like a conveyor, but not for a fan or centrifugal pump.

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  • \$\begingroup\$ and might get hotter! \$\endgroup\$ – Neil_UK Feb 5 '17 at 14:21
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Well, excellent answer given by Charles. The motor will run faster, it'll exceed the its rated speed. While it is not a problem for low torque applications assuming the motor structure is designed to withstand higher speeds, but for high torque applications, it'll really need more current to draw. Only way to feed that current is to increase the terminal voltage.

But, frankly I think using a Variable Frequency Drive (VFD) to achieve 50 Hz if so required in the application rather than using a transformer to do so.

It is costly, but it gives you a lot more freedom. Rest depends on your application area as Charles had rightly pointed out.

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