Electric Motor Secrets

[nali2001]

Old books

That book is to be found here:
(It's by Steinmetz btw) Live Search

Anyway here you can find thousands and thousands of old (from 1800>) books all free to view and download. Here you can find so much of the good stuff you won't believe.
Live Search
Or:
Live Search
Regards,
Steven

[Peter Lindemann]

Pictures Coming....

Jetijs,

Last week I promised some pictures of my coil cores. As it turns out, I just happened to be rewinding my coils with a larger gauge wire, so I could take a new picture with the core both empty and full of wire. I have sent the pictures over to Aaron and he will post them here shortly. This coil is about 250 turns of #12 AWG (similar to 2mm wire).

The plastic end plates are glued right to the sides of the laminated iron cores and the bottom of the winding area is insulated from the laminations, as well.

I hope these pictures help you decide how to handle the coil winding process.

Peter

[Jetijs]

Thanks Peter,
I cant wait to see the pictures although I understand what you are meaning. I have now some other problems. The guys from the machine shop said that the startor plates are glued together forming kind a cone. I you imagine the startor piece and see at it from the thickness side then it would appear something loke this:
|======/ |===rotor===| \======|
I hope you understand. The upper startor plates are closer to each other by about 0.2mm. This means that the top rotor plates will be closer to the startor piece than the bottom ones. This is not good and I have to figure out how to deal with it, because they cant do the lathe work if the startor isn't right and they do not have the equipment to fix the startor. I already have some thoughts, but this will take time.

[adam ant]

could the rotor arms and the stator arms at cut at a slight angle and overlap the arms to make the gap adjustable? you could get it as close as you wanted this way without worrying about overcutting.

[Jetijs]

Interesting idea, Bryan,
But I think that this will put unwanted pressure in the bearings each pulse and that will create friction and wear the bearings out real soon.
That's my opinion, I am not an expert

[Peter Lindemann]

Machining Operation

Thanks Peter,
I cant wait to see the pictures although I understand what you are meaning. I have now some other problems. The guys from the machine shop said that the startor plates are glued together forming kind a cone. I you imagine the startor piece and see at it from the thickness side then it would appear something loke this:
|======/ |===rotor===| \======|
I hope you understand. The upper startor plates are closer to each other by about 0.2mm. This means that the top rotor plates will be closer to the startor piece than the bottom ones. This is not good and I have to figure out how to deal with it, because they cant do the lathe work if the startor isn't right and they do not have the equipment to fix the startor. I already have some thoughts, but this will take time.

Jetijs,

The machining operation to fix your stator piece involves clamping it in a vise between two large blocks of aluminum for extra support, and then using a vertical mill with a boring head in it. The diameter of the cut can be dialed out slowly .0005" at a time. Extremely precise corrections can be made.

Support the stator pieces as much as possible because the milling operation is an "interrupted cut." The set-up is the most difficult. Mounting the stator piece in the vice and then finding the exact center to begin the milling operation. The actual cut should take about 5 minutes. The set-up may take an hour.

Too bad more care was not taken in the gluing operation.

(Aaron should be getting those pictures posted soon.)

Peter

[Aaron]

pics of coils

Hi everyone,

Here are 2 pics of Peter's coils:

[Jetijs]

Nice pics
Peter,
I spent all the time today figuring out how to solve the problem with my startor. There were several ideas that would require to build a mechanical device to solve this problem. Lastly I figured that I could just make a template of the startor plates with a hole in the exact center of the rotor. Then I could attach this template to the startor piece so that the tempate edges and corners lines up exactly like the startor edges and corners. This way I will have the exact point of refference to adjust my selfmade cnc milling machine. So I made the template out of a 3mm thick aluminum plate so that it matches the tartor plates exactly in dimensions.
Now I have to attach this plate to the startor so that the edges are in perfect alignment. Then I will just move the endmill bit of my router to the little hole in the startor so that the endmill bit fits right in the hole. Then I will zero out all axis and this will be my X 0; Y 0 point. Now I will just have to replace the endmill bit to a suitable one and let my router go in circles, each time making the circle a tinny bit bigger
What do you think?
Thanks

[nali2001]

Cores 'n coils

Hi Peter,
That is some hefty gauge you got going there! Any special reason why that is needed? Will pull some amps for sure. You are working with Mot cores right? Man I must have used over 10 Mots the last year... They make great cores for just about anything!

Good work!
Kind Regards
Steven

[Jetijs]

Steven, what do you mean with "Mot" ?

[nali2001]

Mot

Microwave Oven Transformer.
Extreme Electronics - Tesla coil components

Regards
Steven

[Jetijs]

I guess it is true that if you want something to be done, you must do it yourself
I finnaly solved the |==/ \==| problem.



I did it just like Peter said. The hardest part was to locate the exact center of the circle (you can see that I was a tinny little bit off the centre, but that wont affect anything). When I found the centre then I just made my cnc mill rotate the grinding tool in circles, each time with a tinny little bit greater diameter, till I got a smooth finish
I think that somewhere around next week I will be ready to assemble the whole thing. Then there will be only the coil winding left and the circuit part.

[nali2001]

Motor

Looking good Jetijs, Man I wish I had a CNC machine.

Well now, I almost finished my test thingy. It is based on the idea I explained earlier, using existing cores from normal induction motors. only the housing and rotor is custom. Well the rotor is of solid steel and the axle is aluminum. I know the solid steel sucks big time since it will bust in to flames in minutes (due to Eddy Currents) I'm not joking either since I made a experimental generator with solid steel cores at one time and I tell you within 1 minute the cores was over 80 degrees celsius. (rpm doubled under full load though, but that is a different story) But anyway I guess it should be alright for short 'tests'. Extreme care is taken in precision machining. And so I can say that it has an 0.07mm airgap on each side. So a sheet of paper will barely fit. I also have taken metal expansion into account and measured that the rotor will expand like 0.05mm at about 100 degrees celsius. The bearing are conical 'self centering' rolar bearings. And due to the housing construction you can adjust the bearings in case it has some play in it. The stator is not wound at this moment.

Kind regards,
Steven

[Jetijs]

Those are some nice pictures
Thank you for sharing

[Peter Lindemann]

Steven, Great Pics!

Steven,

This motor looks very good. Now that I see the magnetic graph in the last image and see how you plan to run it, this could be extremely excellent. Just make sure you leave enough time for the stator field to fully collapse, and recover all of that electricity, before you turn the next set of coils on. If you do this, your motor should really perform well and prove out everything I have been saying on my DVD.

Keeping the gaps as small as you have them will produce very large torques.

Very, very good!

Peter