Lockridge Device - Peter Lindemann

[pault]

2nd set of brushes

I see two ways of mounting the 2nd set of brushes on the 12VDC (P.A.) motor and I've started (but haven't finished) fooling with both.

0) I think I want the motor to turn CW (looking down, brushes at bottom). This seems to give the the most real-estate for the outrigger springs.

1) Snip the 2nd brush board (tin snips work) and drill relief holes to cozy the board into position and glue it to the main board. It seems that this will require adding another spacer or two on the brush end of the armature to "lift" it up enough to compensate for the added height of the glued-on board. This will mean that the case will not close all the way. I don't see this as a problem. In fact, it might be an idea to add "spacers" cut from the 2nd board scraps between the casing the and the brush end when reassembling.

2) Remove the brush casings and pins from the 2nd board and attach them to the main board, drilling new holes. It looks like it *might* be good enough to attach only the front end of the brush casings to the board and simply let the rear end hang over the edge of the board attached to nothing. The spring pins are "riveted" into the board - I'm not sure how to re-attach them to the main board (force fit into a smaller hole, and crazy glue?).

I'm favouring 1, and will fall back onto 2 when I found out if there's a gotcha ...

Odd point - the bearing on the brush end is not fixed, its a round ball held down by spring metal. You can tilt the axle / bearing assembly. Need to check that it is not tilted off-axis when reassembling.

pt

[Mark]

Matt

I'm wondering if the stock motor your testing might have something wrong with it, is it one from the junk yard or is it a new one?

[Mark]

Pault

My 12 volt motors must be a little different than yours. Both ends of mine have bushings, no bearings. And I think I can glue my cut boards on top of the other ones and wont have any clearence issues.

[Matthew Jones]

Use a glove Mark, you can hold on longer.

I am not running 48 volt anymore I am running 72 volt.

I am not sure of the speeds I'll throw a little flywheel on it and Tach it later this afternoon. Let ya know.

Matt

[Mark]

Ok, tried with a glove and I could easily bury a 5 amp meter with the stock motor and could only get 2 amps out of the modified one. My bad.

[Matthew Jones]

Ok, tried with a glove and I could easily bury a 5 amp meter with the stock motor and could only get 2 amps out of the modified one. My bad.

LOL

[Peter Lindemann]

Saving Money

Ok, tried with a glove and I could easily bury a 5 amp meter with the stock motor and could only get 2 amps out of the modified one. My bad.

Mark,

I'm with Matt. I LOVE the cheap "lab test".

Peter

[Matthew Jones]

Mark
I am getting 3900 rpms (Dead even too) out of the motor, at 72 volt, .5 amp.
and recovers about 36 volt .5 amp (+ or -) per rotation. The higher voltages in the cap are contributed to any spikes produced in the recovery half of the motor.

The stock one runs at 2600 rpms, at 24 volt just under 1 amp.

Thats all free wheeling though. You see things change when you add a mechanical load.

Matt

[pault]

Pault

My 12 volt motors must be a little different than yours. Both ends of mine have bushings, no bearings. And I think I can glue my cut boards on top of the other ones and wont have any clearance issues.

My bad use of words. Yes, I've got bushings. The brush end is held down by a black spring metal disk and swivels if you insert the axle and pull - probably a production trick to allow wider tolerance of fit.

My commutators taller than a brush, but the extra is "lost" below the 2nd board when I push the armature all the way in with only one spacer.

pt

[Mark]

Mark
I am getting 3900 rpms (Dead even too) out of the motor, at 72 volt, .5 amp.
and recovers about 36 volt .5 amp (+ or -) per rotation. The higher voltages in the cap are contributed to any spikes produced in the recovery half of the motor.

The stock one runs at 2600 rpms, at 24 volt just under 1 amp.

Thats all free wheeling though. You see things change when you add a mechanical load.

Matt

Not bad Matt. I tried to run my modified motor today at 72 volts and let a little bit of the smoke out . It happened almost immediately so I wont be doing that again.

The recovery numbers above, are those with the brushes in the stock location, the "generated recovery"? Or have you moved the brushes and that is from the back spike.

My stock motor runs 3355 rpm's at 900ma so either mine is a little different or your maybe a little tired.

Mark

[Mark]

My bad use of words. Yes, I've got bushings. The brush end is held down by a black spring metal disk and swivels if you insert the axle and pull - probably a production trick to allow wider tolerance of fit.

My commutators taller than a brush, but the extra is "lost" below the 2nd board when I push the armature all the way in with only one spacer.

pt

Ok, got ya. Have you fired her up yet or you going to wait till you get the other brushes mounted. I'll let you modify yours first, you can be my guinea pig . So don't mess it up, lol.

Good luck, Mark

[woopy]

another possibility towards the same goal

Hi all

here my testing on a 1 pulse per motor turn

with very good results

the motor is radial and the flux is axial, but the aim is the same, to get as low as possible BEMF.
And it seems to work quite well.

good luck at all

Laurent

YouTube - lockridge test 1

[Matthew Jones]

Not bad Matt. I tried to run my modified motor today at 72 volts and let a little bit of the smoke out . It happened almost immediately so I wont be doing that again.
The recovery numbers above, are those with the brushes in the stock location, the "generated recovery"? Or have you moved the brushes and that is from the back spike.
My stock motor runs 3355 rpm's at 900ma so either mine is a little different or your maybe a little tired.
Mark

Nope didn't move anything. The motor is a new motor. I might have ran it a few time before when it was wound standard. But t has been sitting a while so the grease in the bearing might be sticky. Who knows.
If your smoking there is something wrong.
Did you put a diode on the outgoing side? Whats the number on the diode. May not be up to par. I used a 600 volt 5 amp Ultrafast diode.

Matt

[Mark]

I'll have to look, I was running an ultra fast one on the inside when I had the 20awg wire on it and a 1N5408 on the outside, but I'm pretty sure with the 23awg thats on it now I have a 1N5408 on the inside also. Should I put an ultra fast one back on the inside or is the 1N5408 ok.

Do you plan on moving your brushes or are you just going to leave them. I've been wondering if we even need to worry about the back spike. When the back spike happens the commutator is not touching the brushes so I dont understand why bother with it when we can grab the generated voltage instead and not bother moving the brushes. Your output appears to be better than mine anyway.

Mark

[Matthew Jones]

5408 is kind of a sluggish diode. I would use a fast one.

No I am not planning on moving my brush's all. The thing has got just about the same amount of power as stock for around 36 watts, half or more of which I am recovering and reusing.

I might rewind it and make it bifiliar while firing at each 180 deg point but thats about all I am going to do for now to it.

Add a generator for sure.

Heres a peek at the direction I am moving.
YouTube - Lockridge_Replication.MPG

One thing I forgot and should have waited till I filmed is the heavy electrete effect from the capacitors. Once the motor is shut of and the the battery is unhooked form the system the caps will recharge to about 40 volt.
Thats always a nice thing to see.

Matt