Large Rotors

[zapmk]

Hi all,

Finally got the rotors back from the waterjet guys.

they were made with half inch plate 24 inches round

Now it was time to put them on the hub, and check them

for flatness, they were not to bad ony 100 thousands wobble

on one part of the rotor.

How to start the fun part, taken the wobble out of them.

one of the things I did first was to torque the nuts down

with a torgue wrench, For some reason I started thinking about

disk brakes on the car, uneven nut torque = warped rotors.

Thats better now only 75 thousands wobble. it was time to make

the rotors better, got out the BIG rubber hammer.

and started at it, It took about 2 hours with a lot of loud

ringing noise, got them down to 10 thousands wobble.

time to get it on the Mag's

zapmk

[zapmk]

For got to add picture for the rotor alignment.

 

If anybody would like to have the dfx file,

that can be inported into eMachineShop or Autocad,

it in my files.

Injoy

Mike

[SmoggyTurnip]

Nice rotors.

Why are there so many holes?

I mean the smaller ones for mounting to the hub.

[zapmk]

Hi Smoggy Turnip

Jacking screws,

Didn't draw two dfx files for the waterjet guys.

Plan on threading and pluggin them on one of the rotors.

 Zapmk

[electrondady1]

zapnik , those are great looking rotors. now the fun begins. good thinking about the jacking bolt holes . and good thing you were able to get them straight. i know danb gets his cut in the same manner  but his machinest must be more selective with the raw plate . i know i got some ten inch disk last year . i was prepared to have them faced but this machinest is a real artisan and said whey would not need it . he was right! when i got them home and used a dial indicator as you did. no guff, they were only ought by 4 thou.  i think you should get a credit!

[zapmk]

Hi electrondady1,

One of the biggest problem I had was finding the

steel plate, with out buying a full sheet.

 I think when you go with bigger rotors it going

to be hard to find plate that not have some kind of warpage

from being handel by forklifts ect.

The piece plate I found weigh in at 265 pounds.

the 24 inch rotors weigh in

at 41 pounds each after being cutout.

with the smaller rotors its not going to be that noticable.

They were easy to straighten, But I'll bet you could the

ringging noise a mile away.

Ask for a credit ? that would be hard to do the price

was right, they were cutout for FREE.

Some time it helps to have friends in the right places.

 Zapmk

[willib]

Nice rotors !

a suggestion ; you may be able to take out the high spots by spinning the rotor on the hub and using a hand grinder, if you can keep the grinder moving in the right  direction

[zapmk]

Hi Willib,

I had through about have them surface gound,

like they do with a flywheel of a car. But I

wanted to keep as much material in them as possible.

It surprising how much you can straighten them

with a Big rubber mallet, with time and a lot of patience.

Thanks for the suggestion.

 Zapmk

[electrondady1]

zapmk, i actually did the same thing a few month ago. i needed a platform for a lot of ceramic mags i had collected but did not want to waste a good rotor on them so i used  two g.m. automatic trans flex plates i had lying around. they fit really nice on a trailer hub. one was flat put the other needed a good tune up with a baby slege.

[zapmk]

Electrondady1,

Hey they look great,32 poles nice. Hope to get the mags glued on

this weekend, and start doing some coil testing

next week. Have you done any coil testing on

this puppy yet.

[electrondady1]

i tested a 90 turn 23 gauge coil @60 rpm it gave .3 volts with one rotor. so i was thinking, .3x2(second rotor)x8coils per phase x1.73 for star x 1.4 for rectifyer=11.62vdc. not very impresive. but it's hard to get much power from ceramic mags, especialy at such low speeds. so i formed another two 32 pole rotors

and then turned a total of 72 coils.

so when does a hobby become an obsession, i'm starting to scare myself !! lol

[zapmk]

I thought I would include the picture of how I

straightened the edge up, we my poor mans lathe.

just found out you can't download the dfx file

from here.  I'll send them to you

zapcomp at swbell dot net.

 Zapmk

[willib]

72 coils ! thats dedication !

[willib]

zapmk, did you know that you dont need any resin or epoxy on the rotors for testing purposes.

what i mean is , till you are sure that you have everything where it should be , dont put  anything on the rotors, except the magnets.

i have been using the same rotors in different configurations for months , and not once has a magnet moved , unless i hit it accidenently.

just some thoughts.

[zapmk]

willib,

My thoughts exactly, the 2x1x1/2 40 neo's really grip

the rotors, but I thought I would put a small dab of

glue on them just to make sure they would not move.

then after testing pour the epoxy.

I did have a pattern made for the mag placement.





Hopely I can do some coil testing this next week.

I have some 16 gage wire laying around

to make some test coils with.

Hmmm ? Now to make some kind

drive to spin the rotors with so I can control the rpm

during testing. Got any ideas ?

 Zapmk

[willib]

sure , have you got a fairly hefty dc motor and a FET or two or three  , and a varible resistor(a pot),

it will not work as well as pwm ,because the average current going through the FET will equal the DC current going through the motor.but it should work to control the motor speed..