axial generator with lamination core

[mbouwer]

It is about whether we can shape our own lamination core.
I want to try to make an improved implementation.

[mbouwer]

Side plates to contain the lamination core.
The idea is to make 84 slots / 42 coils.

[mbouwer]

The lamination core can be held together on the circumference with a lot of bolts.
I think I should take stainless steel for that.

[mbouwer]

To the stator support ring I added 3 suspension pads.
Now I want to try to make the shaft and the stator bracket out of 1 piece.

[mbouwer]

The bolts on the circumference press the laminations together.

[mbouwer]

The inner diameter of the lamination core is now ø 130.5 mm
The inner diameter between the bolts that hold the lamination core together is ø 163 mm

So I have 16.25 mm thickness to shape the slots and the bridge.

[bigrockcandymountain]

Do you have a shaper to cut the slots? Do you use a dividing head to accurately space the slots?

[mbouwer]

First I make a drawing and indicate with a centeringpoint where the holes should be.
After drilling and grinding the slots I polish each laminate seperately.

[mbouwer]

Fieldlines inspires me to also get started with an existing lamination core.
36 teeth and inner diameter ø 68 mm

[mbouwer]

The stator must get a suspension ring.

[mbouwer]

The stator lamination core is 60 mm wide and has 36 teeth.

Suppose magnets 20 x 5 and thickness 3 mm on the rotor.

3 magnets in line. Then 34 lines of magnets have to be glued.

Or 17 lines of southpoles. The steel cams between the magnets then form the north poles.

[bigrockcandymountain]

Will you use the existing copper winding, or put your own winding in?

[mbouwer]

Isn't that the big advantage if I can use  the existing copper winding?

[bigrockcandymountain]

Yes for sure it is a big advantage.  Then you need to use the same amount of poles on the rotor as the original motor had.  Hiw many rpm is the motor rated for?

[mbouwer]

880 rpm.  0.25 Kw     400 volts
On the original rotor I count 32 poles.

[bigrockcandymountain]

That would be an 8 pole motor.  The bars on the rotor aren't poles, they are just short circuit aluminum bars. 

I think you could do the magnets just like you planned.  I did both N and S poles with magnets on mine, but maybe just N would work with the steel left in place for the S poles. 

[mbouwer]

Suspension rings for this stator.
The notch is for the leading through of the wires to the terminal block.

[mab]

Hope I’m not talking nonsense, but if it’s full load 880rpm at 50hz, then it’s probably a 6 pole motor with a synchronous speed of 1000rpm.

[SparWeb]

The dataplate isn't very clear - I did some stretching and pulling with photoshop to try to get the detail out.
One thing is clear - it's got a rating for both 50Hz and 60Hz. From the more legible 60Hz data I can get it sorted out.
I believe I can read "1000 r/min" on the lower right but it is more likely to be "1080" or "1088".  Either way these are 10-15% below "1200" which would correspond to a 6-pole motor.

Interesting:  Motors should run at the same Volts/frequency ratio.  If it's designed for 50Hz with an input of 420V, then that ratio is:
420/50 = 8.4

Using that ratio when running on a 60Hz supply:

8.4 * 60 = 504V

But that's not on the label, and neither you nor I have ever heard of a 500V AC supply.  That said, I would expect to see a 480V rating, which is close enough.  But actually the rated supply voltage for 60Hz operation is "440V" on the dataplate. 

I think they built this motor to tolerate a lot of very poor power supply possibilities.  You see some "high-efficiency" motors with specs on the dataplate that require a perfect 240V/480V power supply to get the rated power.  Fair enough but in reality your motor doesn't get a nice perfect supply most of the time.  The builders of this motor were probably aware of that and decided to put realistic values on the dataplate so the person using it wouldn't have to de-rate for losses.

[mab]

I still think it’s 6 pole:

If it were 8 pole it would have a synchronous (zero load) speed of 750rpm @ 50hz or 900rpm @ 60z.
The speed of an asynchronous motor will sag under load, and usually the plate will give full load rpm.

So if the rpm values on the plate are 880 and 1088 (? That’s the uncertainty here) it would have to be 6 pole. If the 880rpm is for 60hz then it’s 8 pole.

Sorry sparweb; for some reason I thought you said 8 pole not 6 pole - only noticed my error after I’d posted - it’s been a long day 

[mbouwer]

FFD  Typ DPIH 71B - 6
at 440 V y      60 Hz     1.0 A      1055 r/m      0.29 kW

It is enjoyable to work on a motor like this because I really want to participate
with the windmillfriends on the forum who are applying such a generator.

[bigrockcandymountain]

Oops you guys are very right.  I just saw the 60 hz and 880 rpm.  I should have swiped right to see the rest of the picture. 

[mbouwer]

Now I have to make an axle and then a hub with the magnets glued to it.

[mbouwer]

The axle gets it's shape.

[mbouwer]

In the rear ring of the stator I made 12 threaded holes to bolt it to the axle.

[mbouwer]

The lamination core and coils are mounted on the axle.

But because it doesn't look like a direct drive with a large diameter ( low rpm ), I don't want to continue with this version for the time being.

[kitestrings]

Did you spin it up at all?  Seems like you put a lot of work, and workmanship, into it.

What's are you thinking to do next?  ~ks

[mbouwer]

Only a study to use a asynchrone motor as generator.
Not made a hub with magnets yet.

It seems to me that I should proceed more in the shape on the accompanying image.

[SparWeb]

Well why not?  The path you have started recently can lead to a robust wind turbine like the ones I have built.

[mbouwer]

Can we say the best start is outbound from a special lamination core? One cannot buy this, but I can try to shape it from the laminations of a discarded  motor.

[mbouwer]

After drilling holes at the circumference, and removing the teeth, the laminations can be re-tensioned with threaded rods to a package.
The inner diameter can be turned out.

I think I have good starting material then to shape a lamination core.

[mbouwer]

The clamped laminates for drilling and then grinding out the 60 slots with a width of 4 mm

[mbouwer]

The grooves will be 6.15 mm deep and the narrowest width of the bridge will be 9.5 mm