Is it possible to run(or at least cause some vibrating movement in) an induction motor by powering it with direct current and turning the power on and off?

I am aware that if not switched on and off, DC can not run an induction motor.

As far as I understand induction occurs when the there is change in the magnetic field. Alternative current is used because the magnetic produced by it varies and rotates.

But as Faraday himself observed when he first discovered induction, direct currency causes a stable magnetic field and at that moment some induction occurs and when the DC is turned off the magnetic field disappears and then induction occurs again. But this time it is in opposite direction.

So I don't expect the rotor to turn but can it at least move back and forth to cause a vibratory movement which can power a vibration-powered generator?

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    \$\begingroup\$ Sophisticated motor drives typically rectify to DC and then use 2 or 3 half-bridges to re-synthesize AC at a desired frequency, you may be able to use basically the same idea without the input rectifier if your DC source is suitable. \$\endgroup\$ – Chris Stratton Jun 7 '17 at 20:12
  • \$\begingroup\$ So you are saying that there are induction motors that can run with DC because they are desinged to do so. Good to know. But is what I'm saying correct? I want to check if my understanding is correct. There is nothing about it anywhere on the google or youtube. \$\endgroup\$ – WVrock Jun 7 '17 at 20:18
  • \$\begingroup\$ No, that is not what I was saying at all. Rather, I said that sophisticated motor drives use an intermediate DC rail to synthesize custom AC. Running an induction motor directly on DC is a very bad idea. \$\endgroup\$ – Chris Stratton Jun 7 '17 at 20:35
  • \$\begingroup\$ So they convert the DC to AC then use that AC. I don't know if the term"convert" is technically correct though. \$\endgroup\$ – WVrock Jun 7 '17 at 20:48

It is possible to cause an induction motor to move by applying short pulses of DC current. However the motion will not be predictable and the applied power will not be at all efficiently used unless the application of pulses conforms to a carefully calculated pattern.

If every other pulse has the opposite polarity, you would be simulating AC. That is the essence of a DC to AC converter.

You can probably use an induction motor as a vibrator with the proper timing of DC pulses, but that is probably not the best way to make a vibrator.


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