Lockridge Device - Peter Lindemann

[FRC]

Flywheel

Do you have a flywheel in between the motors ? I was wondering what results you would get with one in place, and pulsing the run motor.

I am not sure, but shouldn't your output be going to a load or cap at least ?

FRC

[pault]

It wasn't a good idea to use a dead SLAB for the recovery battery. The motor wouldn't start today. I took it apart. The brushes look OK, but the two copper commutator sections are completely blackened (and probably non-conductive).

Is there a recommended way to clean them? I'm thinking of trying Brasso, and/or emery cloth.

The one good thing about this design is that I still have 8 perfectly good unused commutator sections - I can always rewind one slot over

pt

[Matthew Jones]

I just sand them with 400 grit. You can use emory cloth as well.

Matt

[Mark]

Hello Matt

Did you ever get a flywheel made? I found something that works good but needs to be balanced. The top of a old GM air filter housing. The hole in the center is the perfect size and when I ran it on an unmodified motor it had good speed and coasted good after removing the power and connecting the leads to a 12 volt 1 amp light bulb. It does vibrate quite a bit but the weight and size work real well for these little 24 volt motors. Its 15.5 inches in diameter.

Mark

[woopy]

Hi Pault

the better way , i know, to renew the collector after spark errosion is to put the rotor in a lathe and carefully lathe the collector. So you get a perfectly flat and brand new collector. You can do it 2 our 3 time as the collector copper is thick enough. But as i sayd "CAREFULLY"

It is what i did when i was involved in electrical RC car races, where the brushed motor had to support very high amperage and get rapidly black and damaged.

Hope this helps

Laurent

[woopy]

At all

i remember of this fantastic time of my electric RC car races and i forgot to say.

When a small brushed DC motor is intended to work at very high current , it needs a "perfectly brushes /collector adaptation" And if the motor is brand new, the brushes are not perfectly adapted to the collector ( so sparks will happen through the tiny gap between brush and collector)
So a "run in" time is really helfull
So i suggest that you let the motor run some time ( perhaps 1 hour) , at low voltage and current ,before you proceed to the modification.

Just 2 cents

good luck at all

Laurent

[Matthew Jones]

Hello Matt

Did you ever get a flywheel made? I found something that works good but needs to be balanced. The top of a old GM air filter housing. The hole in the center is the perfect size and when I ran it on an unmodified motor it had good speed and coasted good after removing the power and connecting the leads to a 12 volt 1 amp light bulb. It does vibrate quite a bit but the weight and size work real well for these little 24 volt motors. Its 15.5 inches in diameter.

Mark

Ya my guy is working on it. He's busy since he the only one around for 90 miles. Basically just had him run 3/4" shaft through 4 1/4" plates of steel. Then he's going to drill a 7/16" hole in each end and mount set screw to bolt onto the flat spot just behind the thread.
I've haven't heard from him though so its not finished.

Probably next week. The Lower Slower South, ya know??

Cheers
Matt

[n84dafun]

Grinding wheels for a flywheel

Mark,

For a flywheel, you can use grinding wheels stacked together. Here's a link to some grinding wheels that might fit our motor.

Grinding Wheel

They are well balanced and can spin up to 13k RPM. The 3/8 arbor size is slightly smaller than the shaft, which is 10mm, so you can drill it to fit the shaft. I was thinking of getting a metal tube with an inner diameter of the shaft and getting grinding wheels with an arbor size same as the outer diameter of the tube. Then simply slip the wheels onto the tube, which would be longer than the width of the stack of wheels so that you can put a set screw on both ends of the tube for both motor shafts. You would have to epoxy or weld the wheels on the tube.

Brian

[n84dafun]

Grinding wheel flywheel

Here's what I'm talking about. It's a little different from what I described earlier. This one uses coupling nuts and a threaded rod down the center.

Another idea is to simply use the rotor of a spare motor for a flywheel.

Brian

[Hiwater]

lockridge device

I was looking for a Flywheel today for the scooter motor and found an old ceiling fan motor hub. The center hole on the fan motor is just a hair too small, so would have to de drilled..The bearing would have to be spot welded to the shaft on one side. About six inches in diameter and two inches wide. This little unit is just heavy enough to work for these scooter motors, wont know for sure untill I try it out to see how it works. Might be worth a try. Hiwater.

[cwaugs]

A lot of exercise equipment have well built flywheels on them.. HTH wayne

[Robbush]

progress report

I am setting up to test no load speeds at different voltages,I am planning on using a computer power supply (300 watt) to charge caps ( in parallel) to 12 volts, while they are also hooked up in series to go to 24,36 and higher voltages. I have 5 31,000 mfd @ 50 volt caps to use this way. I am going to recover through a bridge rectifier to 76,000 mfd caps rated at 40 volts. Next is to attach a flywheel, I pulled one from a manual treadmill, it has an outside diameter of 8", will weight it and post that with the no load speed results. My problem is that I live in Colorado and the garage is very cold to work in so I am not motivated to go and use the lathe to fabricate a shaft to connect motor to flywheel, I think it should warm up this week and if it does that will be priority to get done.
Keep up the great work you others are doing, and I should be posting some numbers later today. Peace
rawbush

[pault]

The Puller

[I put some classic Steppenwolf on and] I figured out how to convert my motor from a pusher to a puller.

This is a one-coil, 2-pole motor, 10 slots.

I energized the armature outside of the housing and used a bar magnet to determine where N and S were.

It turned out to be simple to do the conversion with this particular motor. I dropped the commutator back by only one section (didn't even need to move the wire, just flip it right instead of left).

The pusher configuration was set to fire the coil when the coil was at about 12:30 / 6:30 at the deepest part of the N-N S-S magnetic field. The N field vector (90 degrees to the coil) was just exiting the N PM field and the S field vector was just entering the N PM field.

This pull configuration is set to fire when the coil is at about 2:00 / 8:00 in the N-S S-N field, i.e. the S field vector is at about 10:00 into the N PM field and the N field vector is at about 4:00 into the S PM field.

2 activations per revolution. 18awg, 30 turns.

Early results:

- at 12VDC, the recovery signal is opposite to that in the push configuration (on a 'scope)

- at 12VDC, the motor runs at 3000 RPM drawing 1.7A-2A.

- at 25VDC, it runs at 4285 RPM, drawing approx 2A (average - the panel meter is bouncing).

I'll have to wait until tomorrow for another 12V battery to be freed up, before trying 36VDC.

Any suggestions? Should I move back another commutator, getting closer to 12:00 attraction?

pt

add: In this motor, the magnets are curved and long, covering almost 180 degrees (less about one commutator width) each. In the previous configuration (that I called push), both, N and S armature arms were in each magnet's field, probably resulting in a push and a pull. In the new configuration, the percentage of S arm in the N PM field is larger and v.v. resulting in more pull and less push, and a reversal (and narrowing) of the recovery pulse. It's not yet clear if this is an improvement over the previous push-pull config.

[pault]

more results

2-magnet, one-coil, 10 slot motor, mod'ed for more % pull, as above, added FWBR (UF4007's) across recovery brush.

12V 3,000 RPM, draws 1.7-2A, charges 4700uF cap to 4.49V in a short run

25.34V 4,285 RPM, draws 2A, charges cap to 6.62V

39.00V 6,000 RPM, draws 2.6A, charges cap to 9.28V

38V back-to-back with same unmod'ed motor (flexible shaft coupler + spider) - ran very roughly, drew about 8A, then stopped and smoked. One commutator looks damaged (discoloured gray-green throughout full depth of commutator, slightly mis-shaped and sticks out more than other commutators, probably unusable without lathing).

Photos.

N.B. polarity differences between push-pull recovery brush and pull recovery brush.

N.B. the "jagged" trace between pulses is the 'scope probe floating when reading open commutator sections.


push-pull (previous mod) 12V recovery brush:


12V push-pull attached to generator (same motor, unmod'ed), upper trace (recovery brush) 0'd at one division below top, lower trace (recovery battery) 0'd at 1 div above bottom


25V push-pull attached to generator (same motor, unmod'ed) 0'd as above:


12V pull (new mod) recovery (0'd at center):


25V pull (new mod) recovery (0'd at center)


pt

[pault]

preparing to rebuild

I have to put this armature aside until I find someone with a lathe (or find plans to modify my wife's sewing machine into a lathe ).

I've got a spare armature.

I'm thinking of winding it with a single coil of 22awg, basically the same as what I've got, but with smaller gauge wire.

Anyone have better suggestions, after viewing the above results?

I only have two magnets (that wrap around almost 180 degrees each with a small gap between them), so I don't think that Matt's mods apply directly to this motor. I have 10 poles - I could try a zig-zag wind, but will it buy me anything and will I need a diode?

pt