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I want to build simple reluctance motor for education purpose. I have couple of small 3 Phase AC Induction motor with 24 slot stator lap winded for 4 pole design.

I want to convert it to reluctance motor, for that I will cast rotor of silicon steel with slots according to ( 24/16 ) design or similar. But as I do not have much winding experience, I want to reuse the existing winding on stator with may be little rewiring of phase ( i.e. remove star / delta, and use all six wire to switching circuit. )

Can this work ? Is this concept possible to work ?

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  • \$\begingroup\$ How are you going to make the control circuit? \$\endgroup\$
    – PkP
    Commented Dec 28, 2014 at 9:02
  • \$\begingroup\$ control circuit could be same as reluctance motor circuit, I think he/she wants to ask about is stator lamination design will work ? \$\endgroup\$
    – iamgopal
    Commented Dec 31, 2014 at 9:37
  • \$\begingroup\$ You can create a synchronous reluctance motor pretty easily. The synchronous motor (or generator) usually has magnets or field windings on the rotor. But even if this is not the case you can get good torque just because of the asymmetry of the rotor (reluctance torque). Even if you want to create a switched reluctance motor in the end, you can try and get the usual three phase sine for testing purposes. A problem though is starting the motor, as you will either need a changeable frequency AC, or bring to motor to speed with another device. This is because it produces torque when synchronous. \$\endgroup\$
    – WalyKu
    Commented Jun 29, 2015 at 7:23
  • \$\begingroup\$ Well, there is another solution, which will make the starting of the motor easy. If you have a IM cage on a synchronous motor, it is called a line start motor. That is because it can start directly when connected to three phase AC. The IM cage produces the torque until you come near synchronicity, then the torque production jumps into synchronicity and it becomes a synchronous motor instead of an IM. You could actually do it by just cutting out slices of the rotor and short circuiting the cage again. Yeah, you can do a lot if you have the tools. Have fun! \$\endgroup\$
    – WalyKu
    Commented Jun 29, 2015 at 7:27

2 Answers 2

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A standard 3-phase, AC motor has the stator windings distributed in the slots to form poles that do not have much saliency. A switched reluctance motor has both salient rotor poles and salient stator poles. You would need to rewind the stator to have a motor like that.

A synchronous reluctance motor has a salient-pole rotor, but distributed windings in the stator to form non-salient poles. To convert an induction motor to a synchronous reluctance motor, you could use the stator as it is and machine the rotor to look something like this:Synchronous Reluctance Motor Rotor Cross-Section

You can get some induction-motor starting torque from the remaining rotor bars, but the best way to operate the motor would be with a variable-frequency drive (VFD). The VFD will provide reluctance torque from stand-still. That may or may not suit your purpose.

Of course, you may have some difficulty with rotor balance.

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  • \$\begingroup\$ don't forget to have the rotor balanced after modifying it. \$\endgroup\$
    – Jasen Слава Україні
    Commented Jul 31, 2019 at 1:09
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The way I see it:

There is a stator with 4 poles (coils are placed into 24 slots). And rotor with 4 salient poles. Then when you apply voltage to stator, lets say 1 phase at a time, there should be magnetic field between 2 pairs (4 poles) of the rotor, that is a principle of stepper motor.

The Y connection seems to be more suitable for stepper motor, because you may power 1 coil at a time. I am not sure though, how to change it from triangle to Y if it is already winded and there are no terminals (separate terminal for each coil).

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    \$\begingroup\$ Having the same number of rotor and stator poles is generally bad for reluctance motors, except with specific design modifications. The problem is that if your rotor and stator poles are aligned you can't start the motor at all. That is because there won't be piece of iron wanting to get closer to a pole, as everything is oriented. \$\endgroup\$
    – WalyKu
    Commented Jun 29, 2015 at 7:17

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