AC Permenent Magnet Motor

[gotoluc]

Hi everyone,

I don't quite know where to post this topic since there is nothing that I know of like it. It involves a permanent magnet and is a motor but it needs a small amount of AC electricity to make it work. Stefan can change the topic location to where he thinks is best if needed.

What I have found is using a Permanent Magnet with continuous Alternating Current (no commutator) going through an Air Core Coil with the magnet in the center as rotor can create motor rotation without switching the power on and off which is much like an induction motor. I also noticed a large amount of Torque compared to when the motor was previously using a commutator since using AC the coil is not really shutting off so the magnet rotor follows the coil activity. The big bonus is, since the rotor is a magnet as it rotates it makes the coil more and more efficient as the RPM increases. The other bonus is, contrary to the induction motor the more the load on the motor the less current it draws ... I don't understand this yet ... however there is a limit at this time due to slip (magnet rotor out of sync with coil) if the load is too much or the RPM is too high the rotor stops and can even reverse. However, I think that much improvements could be made considering the AC I'm using in the video is 50% duty cycle so who knows how far we can take this

The video demonstrates the basic effect using a motor I made a year ago for another project. So please keep this in mind that nothing is optimized and I'm using off the shelve parts I had.

Video: http://www.youtube.com/watch?v=TS4zmXU11A8

Please post your comments

Luc

[Low-Q]

Hi everyone,

I don't quite know where to post this topic since there is nothing that I know of like it. It involves a permanent magnet and is a motor but it needs a small amount of AC electricity to make it work. Stefan can change the topic location to where he thinks is best if needed.

What I have found is using a Permanent Magnet with continuous Alternating Current (no commutator) going through an Air Core Coil with the magnet in the center as rotor can create motor rotation without switching the power on and off which is much like an induction motor. I also noticed a large amount of Torque compared to when the motor was previously using a commutator since using AC the coil is not really shutting off so the magnet rotor follows the coil activity. The big bonus is, since the rotor is a magnet as it rotates it makes the coil more and more efficient as the RPM increases. The other bonus is, contrary to the induction motor the more the load on the motor the less current it draws ... I don't understand this yet ... however there is a limit at this time due to slip (magnet rotor out of sync with coil) if the load is too much or the RPM is too high the rotor stops and can even reverse. However, I think that much improvements could be made considering the AC I'm using in the video is 50% duty cycle so who knows how fare we can take this

The video demonstrates the basic effect using a motor I made a year ago for another project. So please keep this in mind that nothing is optimized and I'm using off the shelve parts I had.

Video: http://www.youtube.com/watch?v=TS4zmXU11A8

Please post your comments

Luc

That is why we use 3 phase AC which has a 120 degree offset that will more easily determind the rotation direction. A 1 phase AC will by accident turn the rotor one or the other way as you use 180 or 360 degree offset. I know of 3 phase brushless motors, small ones, with magnet rotor, and coil stator, with a efficiency of 95% or more. Your motor probably are better synced with load and lower speed, and therfor the efficiency gets much higher, and the amps goes down. Load it more and the amps will go up again.

Vidar

[gotoluc]

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

[powercat]

Yes another great thread from gotoluc 
This reminds me a bit of Thane Heins Perepiteia

all the best gotoluc
cat

[gotoluc]

Hi powercat,

thanks for looking.

You know, I was thinking of Thane when I could feel the Torque on the motor shaft and saw the amps dropping under load!... I though , this is exactly the kind of motor Thane needs

I'll be sending him the link unless someone has already done so

Luc