Author Topic: motor conversion-dismal performance (Read 6517 times)

bart · « **on:** February 18, 2008, 06:34:12 PM »

thanks to all the great people who have and will post their projects, ideas, and helpful comments. been reading and learning alot the past year 1 1/2.

read every thing i could find that zubbly wrote on motor conversions and miss his presence. found peter dingemans article on decogging a fantastic referance and despite crappy output the motor does not cog at all.

info.

motor-gould 1 hp 3 phase 460v 60 hertz 1140 rpm insul. class b amps 1.8 coil wire dia. .275"

was taken out of a 20 year old trane rtu, and was 1 of 6 condenser fans.

ohms on each winding is 9.3 (just taken on the in/out of one winding) and has 6 wires, 2 per winding. was wired in star w/ center tap on a klixon thermal over load. brought out all six wires.

stator is 36 slot and after turning down rotor, installing mags (1/2 x 1/2 round n50's) and cage (3" pvc schd. 40) have about 1/16" gap between stator and rotor. from what i've read, this is a 4 pole motor and have 10 mags per pole. can add more (i think).

at 700 rpm (drill press) am getting 3.2 volts per phase open circut. was really hoping for more and thus am seeking knowledge on what to do next.

just dinking around w/this as its fun. already have done a 1 hp ecm that is basically yard art (for shame!).

now lets see if i can get pictures posted.

http://www.otherpower.com/images/scimages/9873/P1030777.JPG

http://www.otherpower.com/images/scimages/9873/P1030781.JPG

it seems picture posting has defeated me also <sigh>

They are far too large file size to post as photos or I would have fixed it. TW

Flux · « **Reply #1 on:** February 18, 2008, 11:45:12 AM »

That's must be a 6 pole stator, not going to work with your 4 pole rotor.

Pity the picture doesn't show the whole stator, but it looks short pitched for 4 pole and the slip from 1800 is not believable even for a fan motor.

It has to be slip from 1200 rpm.

Flux

bart · « **Reply #2 on:** February 18, 2008, 12:28:44 PM »

flux,thank you for your reply, but once again you have encountered some one with out your depth of knowledge. have no idea what "short pitched" or "slip" means. please educate!

the stator picture is basically 1/3 of the windings and the other 2/3 is repeated from what is shown. i would include another picture of the whole stator, but i've got to learn something else.

6 pole? that's not good. from what i've read, thought by rpm that it was a 4 pole. sounds like its time to turn down another rotor (lots of spares).

TW- thanks, did down size to 640x480 using irfan view, but forgot about the size limitation. will have to see about how to do that also.

kurt · « **Reply #3 on:** February 18, 2008, 01:37:46 PM »

at 60 HZ a 3600 rpm motor is 2 pole a 1800 rpm motor is 4 pole a 1200 rpm motor is 6 pole etc. slip is how much slower the actual speed it turns compared to how fast is supposedly should turn based on how many poles it has like allot of 60 Hz 4 pole motors run at 1750 rpm so therefor they have a slip of 50 rpm the higher the slip the less efficient the motor and the more heat it will make. your motor has to be a 6 pole motor with a slip of 60 rpm.there is no way it would be a 4 pole motor with a slip of 660 rpm. so therefor you are going to have to rework your rotor to 6 pole to get anything out of that motor.

bart · « **Reply #4 on:** February 18, 2008, 02:23:18 PM »

thank you kurt. well, damn. can't find the info. that led me to believe it was 4 pole and guess it ain't gonna matter now. everything i find says 6 pole. time to start another rotor. cut once, measure twice, or with me 5 or 6 times might do it.

now thinking of ways to use the 4 pole rotor, without the existing stator. no, don't want to rewind.

any ideas?

tecker · « **Reply #5 on:** February 18, 2008, 02:53:12 PM »

Looks like the individual pole spacing is too wide also Double check that.

bart · « **Reply #6 on:** February 18, 2008, 03:51:21 PM »

thanks tecker for your reply, but i need to understand what your telling me. do you mean the space between the rows of mags on one pole or the space between the mags in a row? or both?

tecker · « **Reply #7 on:** February 18, 2008, 04:19:28 PM »

The space between the mags in one row .The magnet rows should fit in the middle of One phase with a 10 degree shift top to bottom . I know this hard to discuss , Here's the masters files .

http://www.fieldlines.com/user/zubbly

tecker · « **Reply #8 on:** February 18, 2008, 05:03:30 PM »

I see you've been through Zub's files .Sorry .

Flux · « **Reply #9 on:** February 19, 2008, 01:00:39 AM »

Don't get too bogged down by this, your problem is using a 6 pole stator with a 4 pole rotor. No messing about that doesn't change it to a 6 pole rotor is going to fix it.

Flux

bob g · « **Reply #10 on:** February 19, 2008, 04:20:17 AM »

it is possible to split each and every pole of the stator

rectify each and make it work?

but you have a 6 pole and 3 phases, so you end up with 18 poles/2

or 9 pairs of poles to rectify.

pole spaceing (magnet to stator coil) relationship isn't real good, but

it might be worth a thought...

i think,, but then again it is 3:15 am

maybe i need to go to sleep and see what it looks like in the morning

bob g

bart · « **Reply #11 on:** February 19, 2008, 04:36:41 AM »

1 step backward, 2 steps forward. that's progress. have lots of these motors and started turning another rotor down. will post the results.

tecker · « **Reply #12 on:** February 19, 2008, 05:39:04 AM »

The point is that the core rebounds with the slightest change in magnetic flux and if the mags are not close enough the core pulls in the local flux at the edge of the core segments .Take a mag and turn it to repel scan over the row you set up look for a change in the force you want a very dense scalar pole .Also the pvc will let go and deform with heat that is always there and gets greater around the cavitations . Post a few more pictures of your stator paint all the coils different to identify each ,the starts as well.

Get a fresh start on this . It's good your flexible it should be easy enough to get the mags out of the pvc .

bart · « **Reply #13 on:** February 19, 2008, 06:05:41 AM »

may have to dig into the stator of one that had low mega-ohms to figure out the coils. it looks like the coils , of each phase, gets progressivly larger around the others, if that makes sense.

thanks again, off to the daily grind.

vawtman · « **Reply #14 on:** February 19, 2008, 04:03:54 PM »

Hi Bart

The coils should all be the same size.Its hard to tell with the overlap winding sometimes.

pl=1-8
pl=1-7
pl=1-6
pl=1-5
pl=1-4

That would be the coil span for 36 slot stators.Has the no. of poles increase so does the distance between the poles on the rotor.

Flux please correct me if im wrong.

vawtman · « **Reply #15 on:** February 19, 2008, 05:11:51 PM »

Now that i think about it after a chat with Mr Snowblower(AGAIN).The rotors and stators increase in diameter with the number of poles on factory motors.

Mark

bart · « **Reply #16 on:** February 19, 2008, 08:23:25 PM »

thanks mark for the info. waiting to hear more about your vawt.

snowblower? must be hiding on irc chat or are you really getting the white stuff?

lets see if i can explain this with out screwing it up.

1 coil winding of 1 phase consist of 2 coils. the outer coil takes up 8 slots (or 7 teeth between coil legs) and traced a wire from the outer to the inner coil which takes up 6 slots (or 5 teeth between coil legs). 3 sets of these per phase around the stator.

so now how many rows of mags can be fit? do you use the space between the inner or outer coil as a guide?

bart · « **Reply #17 on:** February 19, 2008, 08:52:24 PM »

grasping..grasping..got it. do feel a slight change between mags. don't know if another mag can fit as the mags on the end of the row are on the end of the stator. or is it better to cram existing mags together for a better fit? or over run the ends of stator with an added mag?

unless the pvc gets bubbly hot, don't see it moving at all. forgot to explain that there was a space between the i.d. of the pvc and the o.d. of the stator. that space has been packed with water proof epoxy (elmers brand, bought at lowes) paste. some of it can be seen on the end of the pvc. cured over night to rock hard - so far happy with it.

bart · « **Reply #18 on:** February 19, 2008, 09:04:46 PM »

thanks bob g, but after destroying 1 stator to figure out coil phases, i think i'll turn down the rotor. easier for me to do than bring out all those wires. on the ecm, for fun i say, i brought out all ends and outs of every coil. but at least they were not all glued together.

vawtman · « **Reply #19 on:** February 20, 2008, 04:52:32 PM »

I check in on irc from time to time yet and maybe will a little later.Did you ask Peter?

White stuff its more like white death and cold has heck.No vawt work during my minny depression.

To get the max fill in a slot you can cut into the top and bottom of the coil space with the skew but no more than 1 slot(per the master)I still think your misreading the coil span.I have painstakingly removed the wire from a motor(5hp 3 ph 4pl)just for fun and wire to play with.

Hang in there and have fun

bart · « **Reply #20 on:** February 20, 2008, 05:41:48 PM »

crap- should have said " o.d. of rotor" instead of "o.d. of stator"

vawtman · « **Reply #21 on:** February 20, 2008, 06:32:40 PM »

Check this out Bart

http://www.uiitraining.com/b51a/100/15104ac_motor_rewind_intro6.htm

bart · « **Reply #22 on:** February 21, 2008, 09:23:07 AM »

http://www.otherpower.com/images/scimages/9873/P1030786.JPG

vawtman · « **Reply #23 on:** February 21, 2008, 03:42:30 PM »

I would use 4 slots for each pole skip 2 slots and so on.4x6 =24 + the 12 skipped =36

You don't need to pack in alot of mags especially when using neos.Skew them 1 slot.

Just what i would do.

bart · « **Reply #24 on:** February 21, 2008, 04:55:10 PM »

got it, thank you

vawtman · « **Reply #25 on:** February 21, 2008, 05:22:38 PM »

Someday i would like to try an experiment using hundreds of tiny neo rods embedded into the skewed aluminum cage bars without turning the stock rotor.

Just for sh#ts and giggles.Don't know till ya try.

joestue · « **Reply #26 on:** February 21, 2008, 05:53:21 PM »

well if absolute cost was a limiting factor, couldn't you melt out all the aluminum and wind copper concentric coils in it, just like a "turbo"alternator?

BTW the slots cut in the laminations typically are indeed slots, so have fun with that. lol I'm only half serious.

You could cut it into 4 pie shaped pieces and use the laminations as pole pieces for a 4 pole PMA. i'd try this first with 2 poles. With a true 1mm air gap you wouldn't need as much magnet volume.

vawtman · « **Reply #27 on:** February 21, 2008, 06:17:41 PM »

Many ways to skin a cat :>)

I've skinned a couple.

One would need to bolt through the rotor lams or attempt to weld in sections somehow first though.They get pregnant fast.

bart · « **Reply #28 on:** February 21, 2008, 06:33:41 PM »

i had to bolt these (already had holes near the shaft) as they where falling apart after the aluminum was gone. i don't think that you would be able to skew the mags though, if they were embeded in the aluminum.

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Author Topic: motor conversion-dismal performance (Read 6517 times)