Lockridge Device - Peter Lindemann

[pault]

Here's an even cheaper motor that appears to be a 2 pole (only has 2 bolts) but doesn't give a lot on info on:
12 VDC MOTOR | AllElectronics.com

I, too, have two of these from Princess Auto.

I disassembled one last night. The two immediate issues I see are:

1) The windings appear to be glued. Initial prodding with a screwdriver makes it seem that the windings are rock solid and may need to be destroyed during removal.

2) It has only two brushes, with an external spring, which uses up realestate and might (or might not) make it tricky to place the 2nd set in just the right place. If I can't find similar brushes at a motor supply house, I'm going to have to scavenge them from a 2nd motor (rendering it useless). The brush mounting board is cut down and not big enough to hold 4 brushes, so it will probably need to be replaced.

@Peter - What is the plan for when we get to the generator step? Am I going to need a 3rd one of these exact same motors to act as the generator (if I scavenge from the 2nd)? There were only 4 left at P.A., I should go back soon if I need the same kind.

@anyone - Will I need 6 12V batteries for this test (3 and 3)? Any tricks for economizing in this department?

@Kyle and other Princess Auto-ans: p.m. me, let's see if we shop at the same place and if we wish to collaborate.

thanks
pt

[n84dafun]

Brian,

I am very interested to see what you have come up with.

Peter

Peter,

Here's what I was talking about from my previous post. I don't see any problems with it working.

Brian

[Peter Lindemann]

Very Interested

I've figured out how to pulse twice per rev a 4 stator pole motor like what Matt, Mark, and I have. This should satisfy all of Peter's criteria. Not only will it pulse twice per rev but it will have that cooling time the motor needs, and also no need for diodes in the rotor. All you need to do is offset the power brushes from 180 degrees to say 135 degrees. Then place the recovery brushes half to one commutator segment ahead of the power brushes. I like half because it ensures that you fully capture the spikes. It would also be good to double up on the segments. The diodes outside the motor prevents "feeding" the charge battery with input power. The second part of trick is to place the contact points and jumpers on the commutator segments in a way so that it will pulse the armature coil one way during the two contacts per rev, and put jumpers between the segments in the right place. Kind of like what I did with my 4 pulse per rev setup. When you see my diagram, it should make more sense.

Brian

Brian,

I am very interested to see what you have come up with.

Peter

[Mark]

Well I unwraped my rotor and wound the first coil. Now I'm totally confused again as to how to wind the coils. I thought I'd just wind 2 to start with across from each other get that going and add 2 more in parallel. I had taken a piece of solder and wound it around a pen to look at how to wind it but now I dont think you can wind 2 coils across from each other and turn it 180 degrees and and fire it again, I think it will just lock up!

[Mark]

I was thinking most of the night and agree with you Matt. I'm going to wind 4 coils with 1 wire. I'll wind each coil on 4 sections of my 20 section rotor so I can maximize the size of each coil and use 2 sections of the commutator for the winding ends.

What a headache! Time to go unwind and start over. My fingers are raw from all the time I spent last night spining the rotor shaft and trying to adjust the timing. Not to mention all the cursing that was involved .

[Matthew Jones]

Well I got it going.
I haven't moved the recovery brush's yet, I left them at 90 deg.
I used 2 commutator sections as one was almost 2 weak to get it to flip. Also 2 sections was just about right for recovery.
But with the incoming power unhooked to the recovery, the recovery is next to nothing. 6.4 volt AC. And as soon as you pull a load off of it, it bogs down. So its only generated voltage.

I think 4 traditional coils wound with 1 wire, N-S-N-S, is probably going to give the most power. 2 pulses per revolution.
Your also going to need to hit recovery point while the power is on so you get the step up action out of the coil.
It would work and recover just like my simple motor. No heat and high amp recovery.
IMHO

Matt

[n84dafun]

2 pulses per rev

I've figured out how to pulse twice per rev a 4 stator pole motor like what Matt, Mark, and I have. This should satisfy all of Peter's criteria. Not only will it pulse twice per rev but it will have that cooling time the motor needs, and also no need for diodes in the rotor. All you need to do is offset the power brushes from 180 degrees to say 135 degrees. Then place the recovery brushes half to one commutator segment ahead of the power brushes. I like half because it ensures that you fully capture the spikes. It would also be good to double up on the segments. The diodes outside the motor prevents "feeding" the charge battery with input power. The second part of trick is to place the contact points and jumpers on the commutator segments in a way so that it will pulse the armature coil one way during the two contacts per rev, and put jumpers between the segments in the right place. Kind of like what I did with my 4 pulse per rev setup. When you see my diagram, it should make more sense.

Brian

[FRC]

Same situation

You need to put diodes as Matt found out, because when the rotor rotates 180 degrees after the pulse, the polarity changes causing a lockup (attraction) condition. So you can only pulse once per rev, requiring the need for larger commutator segments to get past the magnets.
Brian

Although I abandoned the idea of using the fan motor I was working on for a
Lockridge type setup, I experienced this same lockup condition. By pulsing less
the motor operated in a correct fashion.

FRC

[Peter Lindemann]

Sorry Guys

Hi folks,

Sorry for the problems. I had figured this out for a two pole stator and simple windings. When you guys started showing these four pole stator motors, I thought I had figured out how to modify them to my idea, but apparently I hadn't quite figured it out.

It seems that Brian's brush placement and commutator set-up does make the motor work, but it doesn't give the windings sufficient OFF TIME to cool off when we crank up the power. So other problems will show up later.

I will think this through again and see if I can come up with a winding that will work for these four pole stator systems.

Peter

[n84dafun]

With my setup, you don't need diodes in the rotor. I tried to figure out how to do the same with power brushes 180 degrees apart as Peter suggested, but jumpers would not work in that type of configuration. You need to put diodes as Matt found out, because when the rotor rotates 180 degrees after the pulse, the polarity changes causing a lockup (attraction) condition. So you can only pulse once per rev, requiring the need for larger commutator segments to get past the magnets. The small segments in the 20 pole rotor needs to be doubled up as Matt said earlier. Or you can do what I did and put the power brushes 90 degrees apart.

Brian

[n84dafun]

4 pulses per revolution

Brian is using the zig zag pattern on his and his is running. But then I realized with the way he has his commutators set up he is only getting one pulse per revolution.

Please let me know if you get it going Matt.

Mark,

My setup actually has 4 pulses per revolution. Check out the circuit diagram below. That's how I was able to get it to run. Notice that for each quarter revolution, there's always a repulsive condition on the stator magnet from the rotor electromagnet. The poles flip when the current changes direction on the coil every quarter turn. I placed a jumper 180 degrees from the original commutator segment on the positive end and the negative end to make it work, as I mentioned in an earlier post.

Brian

[Mark]

Well that would explain why have spent the last 2 hours trying to figure out why I can't get mine to run. Would get a little kick the it would kick back or lock up. I thought maybe I attached the wire on the commutator in the wrong spot have hace been rototing the brush cover all around the stator trying to get it to run.

Brian is using the zig zag pattern on his and his is running. But then I realized with the way he has his commutators set up he is only getting one pulse per revolution.

Please let me know if you get it going Matt.

[Matthew Jones]

Funny thing that zig zag

I got this thing wound up in the zig zag pattern. But what I didn't realize is it will only pulse 1 time per rotation. So you can fire it 1 time at TDC (according to the windings) but you cannot rotate it 180 then fire again.
So the thing is is you can put the diode internal. Put an out going diode on the end of your windings. This will both do the capture and block power from coming in at the 180 mark.
I am using a 600 volt 6 amp ultrafast diode. At 36 volt with 3.3 ohms of resistance on the wire I will push about 10 amp per pulse on the input. But the voltage should step up ( I think) to around to around 58 volt so the diode should be fine.

I'm getting ready to put it back together and run it.
I'll let ya know.

Matt

[Armagdn03]

What type or kind of diode would catch the front lip? Or is this actually that important ? Or will it be important at higher voltages ?

FRC

Look for diodes with low parasitic capacitance, but can still handle the current rating. The current should not be for the instantaneous but rather the current averaged over time, as this is how semiconductors are rated.

[FRC]

Diodes

Brian,
Thanks for checking that out. The voltage spikes are very fast and most diodes can't catch the front lip of the event.
Peter

What type or kind of diode would catch the front lip? Or is this actually that important ? Or will it be important at higher voltages ?

FRC