Lockridge Device - Peter Lindemann

[Matthew Jones]

@pault
You gotta look at inrush currents.
Say if your motor is wound with 20 awg, maybe 100ft, and your running 72 volt your looking at something like 72 amp pulse for the first one, The inrush. Then your looking at something like 15 amp pulses after that when your induction takes hold.
The pulse may take 1 millisecond and the off time is like 9 ms.Then you average out your 15 amp pulse over 10 ms and it look like 1.5 amp on an analog meter.
Thats all just an example of course but you get the point.

It why it is hard to say that something overunity or not. Pulse motors induction is a whole'nother ball game.

If you have string of 7.5 amp hour batteries that add up to the voltage you need you'll be fine. Those batteries won't be harmed at all.

I'm running 6 4.5 amp hour batteries and they are 6 years old. Brought back to life from a monopole and abused every day. They still have 95% capacity for there rating.

Hope that helps some
Matt

[Peter Lindemann]

None of the Above

If I understand correctly, I shouldn't run my batteries harder than their C20 rate for any appreciable amount of time. Currently the biggest battery I've got is 7.5Ah, with a C20 of 0.375A. This looks too low to run the motor w/o damaging the battery, given the results thus far.

So, I probably need to acquire something more hefty. I have a bunch of choices. I've only been really active in this field since the conference (and only half-way through monopole3).

Would someone with more experience like to suggest what might be the most useful of the below choices (which are roughly the same price)?

a) 20Ah slab + tripler circuit
b) 3A 30V variable bench supply (+ doubler or tripler circuit)
c) 10A 0-250VAC variable transformer + fwbr + fat cap
d) automobile (or other?) battery (+ tripler)
e) Use what I've got (are we going to reduce current draw in future manifestations?) + tripler.
f) ???

Thanks
pt

Dear Pault,

Most of these suggestions are inappropriate for this motor. It needs short, sharp, high current pulses to operate properly. The best supply is what Matt is using, which is a string of 12 volt Garden Batteries. If you restrict the current at the supply, the motor won't behave properly. Even though Matt's motor is showing 1 amp on the ammeter, don't be fooled. This analog meter is really showing an average draw that is more like 10 amps with a 10% duty-cycle.

This motor requires big current pulses to operate, so there are NO PLANS to reduce current in the future. This is not a Bedini SSG, it's a high torque, high speed electric motor!

Your best bet is option "C" with a cap after the FWBR of at least 100,000 uf. Even with this, the Variac will "moan" when the pulses go through!

Make sure you have the recovery brushes in place before using this supply. Good luck.

Peter

[pault]

Advice needed

If I understand correctly, I shouldn't run my batteries harder than their C20 rate for any appreciable amount of time. Currently the biggest battery I've got is 7.5Ah, with a C20 of 0.375A. This looks too low to run the motor w/o damaging the battery, given the results thus far.

So, I probably need to acquire something more hefty. I have a bunch of choices. I've only been really active in this field since the conference (and only half-way through monopole3).

Would someone with more experience like to suggest what might be the most useful of the below choices (which are roughly the same price)?

a) 20Ah slab + tripler circuit
b) 3A 30V variable bench supply (+ doubler or tripler circuit)
c) 10A 0-250VAC variable transformer + fwbr + fat cap
d) automobile (or other?) battery (+ tripler)
e) Use what I've got (are we going to reduce current draw in future manifestations?) + tripler.
f) ???

Thanks
pt

[Matthew Jones]

I am working on a small step up circiut. So you can drive off of one battery. I'll post it when I get going.

Matt

[pault]

First run with 2 sets of brushes

Ran the motor for a few seconds on 13.8vdc, without a recovery battery. Here is the scope trace on the recovery leads:

http://img695.imageshack.us/img695/4778/img0113tx.jpg

2ms per horizontal division, 5v per vertical division.

[removed]

30 turns of 18awg on what was originally a 10-pole, 2 magnet 12VDC motor rated for 10A

pt

[pault]

Finished build

I used super-glue to attach the spring pin islands. I left enough board to clip the anchor to. [Other builders are welcome to do the job more neatly , holes from my earlier attempts got in the way.]

http://img413.imageshack.us/img413/8167/img0107bq.jpg
http://img211.imageshack.us/img211/1018/img0109u.jpg

And then attached the four 14awg leads. Pointed the right-angle spade lugs toward the exit hole and made sure that the braided copper wire to the brushes was not tangled up and move freely.

http://img248.imageshack.us/img248/8652/img0111li.jpg

pt

[Mark]

Got my rotor running beter now. @60 volts draw is 500ma and rpm's are 4420. The timing was off a little. I'm pretty sure I could get the same rpm's with 36 volts with more amp draw if I went back to 20awg wire. If the wattage use was the same should I use thinner wire and more voltage or heavier wire and less voltage? I'm going to leave it for now. But my thoughts are to use heavier wire so I dont need as many batteries. What's your advice Peter?

Mark

[Matthew Jones]

I am going to walk it through the tests Peter wants first. If nothing else comes of it then I'll put it in the bouncer.

Thanks
Matt

[dragon]

Your thinking of incorporating this into your Bouncer project? Should be an interesting marriage.

Your doing great so far, super work Matt ! Nice video on the little screamin' demon as well, your moving right along.
________
Anal deep

[Matthew Jones]

No if you look at the voltage it the coil you get 2 seperate peeks when it comes out. They usually are about half the run voltage maybe just a little less.
But because you do get some spike type behavior you can run a cap. The largest voltage I got out of it, and that was just letting charge up to the max, was 64.7 volt. Thats running 72 volt system.
But really thats just from the spikes the true power is alot less.

If you put a 12 volt load on it it will run about 14 -15 volt at about 1.5 amp. But that slows the motor down.

Its a funny thing. It all new to me. The point is to get the torque out of it at high rpm so thats what I am shooting for.

Matt

[dragon]

hmmm... I was under the impression the voltages were close. Maybe pump the recovery into a coil, "recapture" the collapse - built in boost converter as such. The switch is already there....

I wish I could follow along but I just don't have the funds to buy a motor(s) right now. I'm working on another project from scratch that is related but don't want to detract from what Peter is trying to accomplish with the motors.

For now all I can do is follow along with everyones projects and work on my own design...
________
OLD MAN VIDS

[Matthew Jones]

Why not put it right back into the system to reduce the draw on the source shown below...

Thats exactly what I am doing.

But with 72 volt front end and only 36 coming out of the motor you have to divide the power up somewhere and put it in where its at a higher potential.
So serialize 3 caps and put the power back in the center cap.

Matt

[dragon]

one possible method

Sounds like plan.

The test results that I posted we're just something to give me an idea of the unloaded motor. Also I am trying to use the recovery somewhere. I think I will use it in conjunction with the generator though when I get it going.

I'll keep posting
Matt

Why not put it right back into the system to reduce the draw on the source shown below...
________
Head Shop

[Turion]

My second set of brushes came in, but the caps that hold them won't be here until the 4th of next month, so I am sitting on my thumbs until then. Guess I will have to get busy on some other projects until they get here. Hurry up and wait.

[Matthew Jones]

Sounds like plan.

The test results that I posted we're just something to give me an idea of the unloaded motor. Also I am trying to use the recovery somewhere. I think I will use it in conjunction with the generator though when I get it going.

I'll keep posting
Matt