rotors 2

[picmacmillan]

below i checked the alignment of the magnets on each rotor..each rotor must have north south, north south on each magnet. on the opposite rotor the magnets must be placed so they attract to the opposing magnet. so there will be a north facing a south on the opposite rotor. I have used the jsck screw to lower the front rotor down to see if my alignment is perfect. it must be dead on so you can get the magnets flux to be in line with the legs of the coils in the stator. I used super glue to hold the magnets from moving at this point.

In the picture below you will notice i have marked all the magnets to ensure the proper field is facing out, always opposite. You will also notice the holes for the spindle and the smaller holes are threaded for the jack screws.

I picked up a tip from dan on one of his prior posts and in it he uses duct tape like shown above to remove any steel filings that may collect while you are working.

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  Below is the supplies i use to make my resin. I mixed up 3-1 litre cans of fiberglass resin(used half of everything for each rotor).1 bottle of baby powder,a few squirts of red paint(for color), and the appropriate amount of hardener.

  I also make a makeshift mold to hold the liquid resin until it hardens. It is made from some cardboard sheeting(sometimes called bristle board), and some duct tape, and i just tape it to the sides of the rotor and there we go.

  I also put a circle of wood in the center of the rotor so we dont mold over the stud holes and to make the resin go farther. This is also the reason i use baby powder(also known as talcum powder). I find the resin is expensive, and it goes alot farther by adding this cheap baby powder.The last thing i do is put some bricks on the center piece to hold it down firm so the liquid doesnt seep under the wood.

BR>

below is what the mixture looks like before stirring.

Below is the rotor and resin drying. This particular one was dry in less than an hour.

All thats left to do is prime and paint.

the machine is going to be red and yellow. I also put a coat of clearcoat on it and it looks alot better in the sun than it does in this phot, but it is getting late and not much sun left..hope this helped some folks..pickster

[harrie]

Great looking rotors, but I see 12 mags, and 12 coils??? hope you didnt make a mistake, or does your dog have a metal collar and mabey took off with the other four mags. I think it should be 16 on each rotor, but maybe Im not understanding what your doing. Or maybe these rotors are for a 9 coil stator?. Harrie

[DanB]

Yes...that has me wondering too pickster.  Mine has 16 magnets and 12 coils...

[Ungrounded Lightning Rod]

Your magnets don't have to be DEAD opposite.  (It's just good execution if they are.)  What matters is how much flux transitions between the inside and the outside of the coil, and how fast it does it, not what angle the flux is at when it cuts the coil wires.

Get it TOO far off and you'll make the waveform a tad wider and lower slope, as the flux doesn't initially cut all the layers of the coil at once.  And misalignment effectively increases your gap a tad, reducing your field strength, too.  So the squarer the better.  But you don't have to get upset about a misalignment of a few percent of the magnet's width.

[dinges]

Looks nice.

But in the last picture of the red rotor, it looks like the hole in the inside of the rotor-casting is not in the center; you might want to correct this, as it causes an imbalance that, at higher RPMs, causes vibration and excess wear.

Peter.

[picmacmillan]

update to my posts...i made a huge error on how many magnets i have...like i was told there is only 12...i thought i used 16 as there seemed to be the right amount as i finished up the rotor there wasnt any left...i forgot though that one package of these magnets has been stuck to the back of my truck seat, and forgot about them til now...i looked down at the magnets that were left and at the time there was 4, which coincide with how many i needed to complete my last rotor.....thanks for noticing for me...today will go a little differently than expected..i will have to knock those magnets off,all the fiberglass resin and redo the rotors...i am out at least %50 bucks and alot of time...costly mistake...i have heard many stories over the years that the engineer is an idiot...i did not know that i was the one they were talking about until now ,..well, enough snivelling, back to work ..pickster

[dinges]

I'd go a little differently;

Leave the rotors as they are;

build a new stator with 9 coils.

In the future, for a next genny (I'm assuming you will be building more), you can use the old stator with 12 coils.

But, your opinion/need may differ of course.

Talking about goof-ups... This is about as big as they go, I think

Very sorry to hear about this.

Peter.

[picmacmillan]

  well, i have taken the magnets off the rotors..they slid right off, and now that i have seen what fiberglass resin does to hold the magnets in place, i would not use it again. It did absolutely nothing to offset any centrifugal forces it would encounter.

  Once the magnets came off, which was so easy, a 3 year old girl could have done it, i then knocked the fiberglass resin off with a few,(very few) short taps with a hatchet.

  The resin came off in one chunk, and i am certain that it would have blown off while in operation anyhow.

  I will find a substitute for holding the magnets in position. Just for the record, i had sanded the rotors clean and they were rough enough to take a hold of the resin.

  I believe when the resin dries, it actually shrinks, so the resin pulls ever so slightly away from the magnets and the rotor itself. To those who might try this, my advise is "DON'T!.

  I have heard from ibedonc and others that jbweld works well, and i have used durabond 2000 with good results.

  Danb suggested making a band around the rotor to hold the magnets in place also...anyhow, i will let you know what the solution to this problem is in a day or so ..anyone needs a picture frame that looks like a flower, i have 2 of them cuz thats all i can see the resin being good for now lol ...pickster