AC Permenent Magnet Motor

[gotoluc]

it seem a synchronous motor with air coil

http://en.wikipedia.org/wiki/Synchronous_motor

Hi wings,

thanks for looking at this topic and posting a link to a Synchronous motor explanation. I had also done some searching before starting this topic and also found Synchronous motors to be close!... however, if you read the description it say the rotor has brushes.

"Synchronous motor is like an induction motor except the rotor is excited by a DC field. Slip rings and brushes are used to conduct current to rotor."

Thanks for sharing

Luc

[gotoluc]

Hi gotoluc,

Interesting video and I did something similar with my Newman motor V 1.0 driving it with my signal generator using square and sine waves last year. I did not have a ammeter connected so it went by as an interesting experiment.
I think that as you increase the load, the magnets does not create as strong a CEMF and the load diminish. Same as when you load the generator with the light but the speed drops faster and the rotor bucks to a stall. Same problem as you increase speed the CEMF makes the rotor lose sync.

Thanks for lighting one more cell in my poor brain.

Keep up the good work.

Michel

Hi Michel,

thanks for taking a look at this topic and posting.

Very interesting that you tried your Newman motor with your SG. Maybe you want to try it again and see if you come up to the same thing that I'm finding or maybe more. One thing to note is when a load is added to the motor it has absolutely no drop in rpm unless you go beyond a certain point and create rotor slip which will stop the rotor.

Thanks for the positive comments and sharing.

Luc

[gotoluc]

This is very interesting indeed.

I think the key to this motor is tuning it to the load like you said. When you load it you have to make sure the load does not have a bigger torque than your motor. If you can fine tune the load just where it almost equals your motor torque I then believe this spot will give you the lowest input current and highest efficiency results. Loading the motor any more will bring it to a halt like you have seen.

Also how does the motor do on higher frequencies than you just have shown?

Hi broli,

I'm glad you're looking at this and seeing so quickly the potential of this motor.

As you explained we could use a finely tuned fixed load to take advantage or we could have a rotor with many poles (demo has only 2) so the rotor has equal torque throughout the 360 degrees. The other thing that could be done is have multiple AC phases off sync in a way so we don't have any zero point.

I believe higher frequencies are defiantly possible however more voltage will be necessary. My generator output is quite limited at 20vpp.

Thanks for sharing

Luc

[Low-Q]

Hi Vidar,

thanks for looking at this topic. That was also one of my thoughts to test with multiple phases.

Could you post a link, picture or something on a magnet rotor AC induction motor as I had no idea they existed.

Thanks for sharing

Luc

http://en.wikipedia.org/wiki/Brushless_motor
If you want one, you can go here: http://www.hobby-lobby.com/brushless-axi2814.htm
I use this particular motor on a RC-plane - 110mph average, with 50 amps flowing through the coils at most. These motors are very powerful to its size. They are so called outrunners, as the 14 pole magnetic rotor is surrounding a 12 pole stator winding.

Vidar.

[Tempest]

http://en.wikipedia.org/wiki/Brushless_motor

I use this particular motor on a RC-plane - 110mph average, with 50 amps flowing through the coils at most.

Vidar.

Did you mean .5 amps and not 50 amp, because that would be one hell of a rc-plane

@ gotoluc

What you have there is an ac synchroness motor. They are used in the machine tool environment. Usually used with an encoder, resolver or tachometer. This way they can know precise speed, position and rotation. They almost always have a certain type of motor drive per motor. The wave form is sine wave because this makes for a more fluid motion. These motors can move very small amount with great repeatability (.0001 of an inch). Also they can hold that position to that degree.