Combination of two 3-phase motor to a 6-phase motor

[Harmony]

Hi everyone,

I'm trying to combine two 3-phase motors to create a 6-phase motor. I'm having trouble finding information on how to do this. Does anyone have any experience with this?

Here are some of the specific questions I have:

• How do I connect the windings of the two motors?
• What type of controller do I need?
• Are there any special considerations I need to make for the power supply?
• How do I handle the torque on the two 3-phase motors?

I would really appreciate any advice you can give me.

Thanks,

 

[neptronix]

Why do you want to create a 6 phase motor?
More complexity and expense on the part of the controller.. and i have never heard of a benefit from going above 3 phases..

In these rare configurations of 6 phases, it's typical to design it so that you have two controllers who see each motor as 3 phase.. this allows you to skip building a custom 6 phase controller..

..& you can achieve this with two 3 phase motors without fabrication/rewinding/etc

 

[Harmony]

Hello
Thank you for your response

The current two 3-phase motors and controller occupies a lot of space, and we were tasked to convert it into 6-phase with the same amount of torque. So i have to design the 6-phase on motor CAD first before implementation. But i do not know how to merge the properties together. Is there any reference that can help, especially as regards winding configuration and controller.

 

[neptronix]

You'll need a custom controller too.
Would save you a lot of work to just make/chose a more compact 3 phase controller, 6 phases isn't more efficient.

 

[amberwolf]

Making it 6phase won't make it any smaller to do the same job.

If it has to do the same work, it'll still be the same size, all other factors the same.

If you want more torque out of a smaller motor, rather than increasing the phase number (which will mean custom designing an expensive motor, and custom designing an expensive controller for just that motor) you spin the motor faster, and gear it down mechanically to get the same wheelspeed but higher torque.

See the simulator at ebikes.ca or any of the gearing/etc simulators / calculators on the various webpages out there for how this works.

 

[afzal]

+1 to comments from @neptronix & @amberwolf

What would be the angle between your windings for the 6 phase machine ?, 60deg ?, then it is actually 3 phase; 2 sets of 3 phase windings in reverse - visualize 3 phase winding spaced 120deg.

6 phase machine is made by 2 sets of 3 phase windings placed 30deg apart, see here. A major advantage is to reduce torque ripple when fed by a square or quasi-square wave, with today's sine wave controllers - no difference.

Motor (rather machine) is designed for torque and torque is proportional to length * square of diameter.