Motor Powder Poles

[Dkirven]

I am fabricating a multipole induction motor with a very small rotor. I will machine ferrite wedges and secure them together to make motor poles. I need large ferrite disks 2.5" diameter by 1 inch thick to make the wedges. I want a high mu powder that will allow about 100000 Hz switching. Where can I find a high flux machineable ferrite this size?
I can press the powder but I cannot sinter it. Is sintering necessary? Thank you in advance.

Doug

 

[sreid]

Magnetics, Inc is the first to come to mind.

http://www.mag-inc.com/

Ferrite saturates at a relative low field strength (5000 guass). You might be better off using powdered iron.

 

[Skogsgurra]

Yes, you need to sinter it. And probably encase the rotor in a composite fiber sleeve so that it doesn't explode at those high speeds. Are you really going to feed it with 100 kHz? Iron powder will get too hot at that frequency. Ferrite is what you should use. But 100 kHz???

Gunnar Englund

http://www.gke.org

 

[Dkirven]

The rotor diameter will be <0.5 mm.

 

[Skogsgurra]

You better tell us more. Me, for one, is getting very curious now.

Gunnar Englund

http://www.gke.org

 

[MacGyverS2000]

I'm getting curious now, too. If the motor diameter is <0.5mm, why do you need ferrite disks 2.5" in diameter if you're machining them down (compressing from that size I could understand).

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Dkirven]

The prototype motor windings and pole pieces are 2" diameter. The pole pieces are wedge shaped with the inside making a circle about 0.6 mm. The 2" size of the pole pieces allow for easy hand winding.

 

[Skogsgurra]

OK. So the ferrite is in the stator! Got it. And what are you using for the rotor?

Gunnar Englund

http://www.gke.org

 

[Dkirven]

Thr rotor is a small diameter conductor. The stator is the windings and powdered ferrite

 

[Skogsgurra]

Sounds very exotic. What speed (kRPM) are you getting?

Gunnar Englund

http://www.gke.org

 

[Dkirven]

We will need at least 100 KHz or 6M RPM.

 

[Skogsgurra]

WOW! That's some motor! Any links?

Gunnar Englund

http://www.gke.org

 

[MacGyverS2000]

I'm not about to do the math right now and ruin the peaceful state of my currently blank mind, but 6M rpm at 2" diameter seems like it would be some serious centripital forces.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Skogsgurra]

No. That's what I also thought. But rotor is a mere .6 mm! Like a thin lead mine. I am getting very very curious. I shall have a go on forces when I find my little formula book. Interesting.

Gunnar Englund

http://www.gke.org