6 pole motor, 4 pole armature

[nothing to lose]

Awhile back I posted I was trying this motor as a 6pole 6pole and cogging terrible, needed a wrench to turn it. Sorry I am not keeping up on things, lots of stuff going on here but getting better now.

So last night I worked on this motor a bit. It was suggested by Jerry that I use 4 poles on the armature instead of 6 to reduce cogging and then seperate the coils. I did this last night it works far better but still alot of cogging.

This is what I have now, but not new pictures.

I took out the burnt coil, was 160 turns there give or take my mis-counting if any.

I broke each coil into a seperate coil and let the start and end dangle loose out the back of the case. Then I made the armature up of 4 poles, 1/2" disks, 4 disks to a pole like this,

That is the old 6 pole picture, but I made the poles the same, about 90 degrees apart.

When I put this back together then as 5 seperate coils it turns far easier than it did with 6 poles, but the 4 poles still cogg allot. I put this in the small drill press, the slowest speed is about 760rpm so I tested 1 coil abit at 760rpm.

As it is wound now, 1 coil gives 5.4Vac open volts, bridge rectifier will give 5.4Vdc open volts. Short circuit amps was about 2.4 I think.

So I wired up some dead Ni-cad cells I had on hand for about a 4.8-5.2V load. These were DEAD like a string of four cells was 1.5V total.

At 760rpm one coil brought the dead cells up to 5.4V fast. I tried to get an amp reading and once saw well over 1 amp for a second then dropped fast to almost nothing.

 I don't think the Ni-cads were enough load but was all I had handy for near 5V.

I won't be finishing this motor for while, I will probably rewind that empty coil pole with same size wire and allot more turns, then take it out and wire with heavier wire, 2 in hand etc.. and see what the one empty coil slot can do. When I find what I like best then I'll wind all 6 coils the same. I think this wire was about #22 or #24 but not sure. Lost my calipers while moving into the old trailer this last week.

I have a ton of #24, well about 20lbs or so anyway. I think I will re-wire with that 2 in hand first and see what one coil does. Lots of room for more wire in this motor.

 The goal is a lower RPM 12V genny and reduce cogging a bit more.

Didn't get any new pictures of anything. I was working with a 5watt HF 12V CFL from the HF solar panel kit and it was hanging from the ceiling to see around the room dimmly.

My main work light was Reall Nice 11watt 12V CFL I got from Ghurd. I bought 2 of them but only using 1 right now.

 For my work light, I cut the cord off a nice normal floor lamp I had handy and soldered on aligator clips. I clip the lamp to a 17amphr SLA battery and have Ghurds 11Watt CFL installed. So far the normal AC light switch is working fine, I must have turned it on/off a 100 times by now. This gives me a nice movable lamp right near where I am working and lights the room nicely also.

NTL

[vawtman]

Remember NTL that the coils have nothing to do with cogging.

 I think your mags may be too fat or strong for the rotor.Maybe

 An opinion.

[nothing to lose]

 thanks,

I know unless shorted or such coils don't do anything, those big fat metal pieces the coils are wound around are the problem. Would cog the same without coils.

If I take half the disks off per pole I think I could reduce the cogging allot, not sure how much power I'll loose yet.

Most the motors I've done are more like the 36 toothe type stators, first one like this I have tried I think.

[powerbuoy]

I believe that the cogging problem will persist due to the fact that you have relatively few teeth in your stator packet, instead of calling them teeth one could almost say pole shoes ... you tried to counter by skewing the magnets which did not work. Skewing the stator would be way better but that's out of the question since this is a done deal. I almost believe that you will not be able to remove the cogging factor from this unit.

Powerbuoy

[hiker]

had one of those a while back--used ceramic block mags on it-about 50watts output..

cogging wasnt really a problem with it--could turn over with your fingers..

those were LOWES ceramic mags that i used--buck 98 for two.......

well good luck with it.....

[Jerry]

Hi NTL.

When I converted  that same type motor, I used the old #29s. They actully covered both slots on either side of the pole.

Cogging was so slight that all was needed was a thum and forfinger to spin the 1/2" shaft. #29s were not skewed in any way.

Do you still have any of your smaller #29 style magnets? They may cogg bad? They are about the size of one shoe.

The old #29s might be the only answer for this type motor. I know when I used 6 of the #29s it allmost requiered a pipe wrench to turn the shaft.

At that time 3 phase and 4 magnets on this 6 pole (6 shoe) motor never ocured to me.

                    JK TAS Jerry

[nothing to lose]

No Jerry I am out of #29 right now. I was short on cash for a time, and now I been spending allot on other stuff and haven't ordered more yet. 4 HF solar panel kits, Steel Blade Hubs, Solar Controllers, 195? old truck, Mazda RX7, it all added up fast in last couple months.

This needs to be a cheaper unit when done so I would like to not use Arcs for this anyway. Even at 24 disk Neos, maybe a total of $8 in magnets.

If the #29 covered both slots on either side with little cogging then maybe I should try adding a 3rd row of 2 disks? Or an odd disk on each side? With this setup 4/6 I think only 2 coils 180 degrees apart should be making power at any one time. In such case if the Magnet poles are overlapping side coils it may not hurt anything permformance wise? I think I will give that a try just to see what happens. I can always pop them back off.

I think I keep thinking more of other types of motors and what works with them is not the same for this one. Being I have 4 magnet poles and 6 coils, I have 1/2 a coil between each pole not being used. Something like that. So perhaps if I make the poles wider to cover part of each side Shoe?

Right now I been using the 1/8" thick disks still and have the cogging problem like this, I have 1/4" thick disks also but those would cog far worse, though may make more power of I get past the cogging problem.

[ghurd]

Whats the ID of the stator?

G-

[hvirtane]

It is a bit hard to tell from the pictures, but it seems that the poles are too wide? In principle the magnetic poles should fit inside the coils.

- Hannu

[Ungrounded Lightning Rod]

Cogging is just related to the spacing of the magnet poles versus the stator poles.  Try changing the offsets between the front and back magnets on your rotor.

By the way:  That was a "shaded pole" motor, with little shorted turns around part of the stator's poles to create a quarter-cycle delay in the magnetization and demagnetization of the part of the pole piece that penetrates the shorted loop.

In a magneto application that "shorted turn" acts as an electrodynamic brake.  If you haven't done so already be sure to remove them - or at least cut a chunk out of each of them to break the short.  Otherwise your genny will have a lot of drag, wasting power heating the shorted turns.

[nothing to lose]

Thanks, I do have some Lowes bars here somewhere I bought long ago.

If I don't do better with the disks I may go that route.

Did a little better tonight.

[nothing to lose]

Thanks for telling me about the shaded pole, I did not know that.

 I think since I need to rewind 1 coil anyway I will do them all same time. I am testing as is though on one coil. The is plenty of room for more wire or larger wire.

Where would I normally find the shorted turns, at the end outside turns?

I think I may have run into a problem perhaps with those tonight, I added a 5th magnet to the poles, cogging went down, amps went up, got stiffer to turn but not a normal cogging, was like brakes or a shorted genny for braking.

[tecker]

Looks like an AO smith motor I have several of these that come from fans 1/6 hp 110 I think . The angle of the magnet offset I think should be the width of the space between the core segments . Check and see if the adjacent coils are reverse wound for a single phase setup . 150 turns in a small coil might not give  you something to JR to single coil. You have to have 1 to 2 ohms for a 500 rpm 12 volt cut with power. The 6 pole looks right If it still cogs the magnet pole is too wide. I have to admitt I haven't even cracked one of these apart but the design is like a ceiling fan motor core inside out .

[nothing to lose]

Well tonight I added a 5th disk to the poles, making the 4 poles a bit wider.

I tested before and after in the drill press. Open DC volts stayed about the same, I think that was right at 5.4Vdc with just one coil, 760rpm.

 However the shorted DC amps were 2.4amp before the added disk, 2.9amp after the added disk. So even though the poles are much wider than the shoes or coil center the amps went up 0.5amp

I used a dead 4 cell Ni-cad string again for a load, when first starting the press up the amps to the cells were 2.9amp I think but went down so fast hard to tell, the cell string volts came up fast and amps went down. The amps evened out at 0.28amp after running a few minutes and held steady. The cell string volts after this were up to 5.4V

This is only 1 coil. And still the RPM was the lowest setting of 760rpm on that press.

The cogging went down after I added the 5th disk, however the motor itself got stiffer to turn. Like when shorting out a DC motor for breaking, gets stiff to turn by hand.

The post about shaded pole and shorted turns above I had not read yet then, so perhaps the shorted turns were making a breaking force like a DC motor? I could still feel a little cogging, but not as bad as before.

I may add a 6th disk and see what happens, the armature will be pretty full then with not much gap between poles. Since I am just sticking the disks on with superglue it is easy to pop them back off, so if 6 do bad I can pop one back off.

After I test with 6 disks for the 4 poles, then I think I will take all the coils out and rewind them, lots of room for more turns or thicker wire. I'll check the cogging and stiffness when there are no coils also.

That one burnt coil I took out was pretty bad, I had black flakey varnish all over the bench and me. The rest of the coils seem to be working ok, but I found some are a bit darker than I noticed before, so they need taken out anyway.

I'll try to get some new pictures as I build the last pole configuration and rewind it for how I actually build it.

[ghurd]

The shorted part is in the lams, in a slot in each pole shoe, almost under the coils.

Some are like 2 loops of #12.  

Mine like that this motor are just a single thick flat copper piece, not even looped.

Looks like a heavy conductor that has no reason to be there.

Spdlmt150 has a photo here...

http://www.otherpower.com/images/scimages/7210/stator_wireremoved.jpg

G-

[Ungrounded Lightning Rod]

Looking at the picture of the stator:  See that little lump of what looks like heavy copper sticking out under the coil on the clockwise side of each pole piece (with a slot in the pole piece where it is)?  That looks like part of it.

That's probably where it's emerging from the slot and then wrapping around the nearby side of the pole - perhaps just under the coil.

The one at 8:00 is especially visible in the picture.

[Ungrounded Lightning Rod]

The cogging went down after I added the 5th disk, however the motor itself got stiffer to turn. Like when shorting out a DC motor for breaking, gets stiff to turn by hand.

The post about shaded pole and shorted turns above I had not read yet then, so perhaps the shorted turns were making a breaking force like a DC motor? I could still feel a little cogging, but not as bad as before.

What you observed is completely consistent with the shaded poles acting as brakes (or with a coil shorted - but you removed it before that test, right?):  Adding the magnet increased the current in the shaded pole windings and thus increased the braking force.

With no load on it the motor should turn freely (with vibration from cogging) once you've gotten it moving.  Give it a push to get it going and it should spin around, gradually slowing down, until it gradually loses enough energy that the cogging catches it.  Then it should oscillate back-and-forth, coming to a halt gradually.

If it's fighting you significantly once it's over the first "hump", stops quickly, and doesn't swing back-and-forth much when stopping, there is current flowing somewhere.  In this case it's no doubt around the shorted "shading" turns.

[nothing to lose]

Yes, I beleave you are totally correct and that is what I think is happening. I did take out the burnt coil, but I have not done anything since learning of the shorted "shading" turns.

This crazy weather has me slowed again, should be warm and I need more fire wood AGAIN.

Thunderstorms today and if it gets any colder probably ice tonight! Dead center of USA this is nuts for weather right now.

[nothing to lose]

Thanks again, I see that there.

I will be taking out all the coils and rewinding, so I will be sure to get those out also. I will look for cogging and braking force before I re-wind it, make sure I have both fixed.

[Ungrounded Lightning Rod]

This crazy weather has me slowed again, should be warm and I need more fire wood AGAIN.

Thunderstorms today and if it gets any colder probably ice tonight! Dead center of USA this is nuts for weather right now.

Any more Global Warming and we'll all freeze to death.  Where's Al Gore when you need him?  B-)

[tecker]

I think nothing will ever happen untill they're  burning bodies in the cities to stay warm

[nothing to lose]

Well I don't really want to get into a debate on Global here, maybe in rant/opions though.

But yes I agree though "Any more Global Warming and we'll all freeze to death. "

And starve to death. Athough the poles may be 6-11 degrees warmer where does that leave the rest of the main reall world, 10-20 degrees colder! That is not global warming it is poor global averaging! And the fact that the earth shifted on it's axis has nothing to do with air polution but it certainly could effect everything we use to know about life and seasons and storms etc.. and none of the collected data for the last 200 years may be correct now for the next 1-20 years to come untill new after shift data can be collected!

 If a topic is started on this in rants/opions it would be a good place and I might participate in a discusion there with some opions of my own on this that few talk about.

[ghurd]

The pole shift can be proved in sediment layers.

Many times.

We are due...