Lockridge Device - Peter Lindemann

[Matthew Jones]

That one kinda got screwed up. I built it 90 deg out. and when I turn it everything gets too tight on one side.

I am expanding the commutator now.

I tried 72 volt last night and it runs 1/2 amp. and charges a cap almost immediately to 50 volt.
But you like said 60 volt takes 1 amp. I am not sure whats up with that.

If you put the out put directly to a battery thats a big load, and that why its bogging down. If you could switch the power off of the caps real quik while the discharge coil is unhooked on the commutator. You could get the power out with out even slowing the motor down.

Matt

[Mark]

Mark, is it this one?:

12 VDC MOTOR | AllElectronics.com

That's the one I'm working on. I took a sample of the wire to an electronics supply place and the guy measured it with electronic calipers and said "probably 18awg". Felt that way when I compared with 16/18/20. The caliper reading could have been off, due to left-over varnish.

I got the rewound motor running with 30 turns, 18 awg.

Yeah, the 2nd set of brushes will be a puzzle. First, I'm going to check the direction of rotation and figure out which side of the existing brushes the new brushes need to go.

One thought is to remove the outrigger springs and replace them with internal compression springs (plugging the end of the brush casing) to free up space to the right of the brushes.

pt

Yes that is the motor, I bought 2 of them. 18 awg, ok I thought it was a little small but I was just eye balling it. I have quite a bit of 18 and 20 awg so I can go either way.

I pulled one of the motors apart and put it back together and I just love the brush assemblies, just pull the spring back and onto the side and the rotor goes on sooo easy. The other motor is such a pain compared to this one. It would be nice to find a way to keep the brushes the way they are.

So at 72 volts the other motor draws only .5amps. Huh, what the hell is going on there.

Something else funny is going on with my 24 volt motor. When I'm collecting the back spike into a cap or battery and have a meter hooked up to it the reading jumps around. It will be steadily climbing lets say from 30 volts and then all of a sudden will read like 3-12 volts for a split second then go back to where it was and continue to climb. Like its getting some AC voltage or something. I've tried some ulta fast diodes, 1n5408, and a FWBR externally and also have a 1n5408 on the winding internally and it still does it. It happens every 5 to 10 seconds or so. It just hiccups for a second and then continues on where it left off on the voltage climb. Even with a battery hooked up, the voltage will suddenly read 3.27 volts or something and then go back to battery voltage. Do you have any idea what going on there, or is my meter ready to take a crap again. I've only ruined 5 or so already in that last 2 years, lol.

Mark

[Matthew Jones]

I would stick with 2 commutator section on the 16 pole motor.

It runs on 3 sections but the voltage steps up to high and must be arching inside. It immediately runs the cap up to near 100 volt. BUT, the motor draws 4 amp at 72 volt. NOT GOOD.
It becomes a basic step up voltage transformer. And I would expect it does not spark much it really isn't any stronger that it was before. So that is an indicator that most of the power that is coming in is going out to the discharge side.

Matt

[pault]

Yes that is the motor

There are a few others here that are using or intend to use this motor.

... just pull the spring back and onto the side and the rotor goes on sooo easy. The other motor is such a pain compared to this one. It would be nice to find a way to keep the brushes the way they are.

Yes, very good point.

pt

[pault]

pics

Pulling the original windings off:
http://img401.imageshack.us/img401/5069/img0097wx.jpg

30 turns of 18awg, just before first run at 12VDC:
http://img831.imageshack.us/img831/9620/img0098yc.jpg

pt

[Peter Lindemann]

Meter Sampling Rate

Something else funny is going on with my 24 volt motor. When I'm collecting the back spike into a cap or battery and have a meter hooked up to it the reading jumps around. It will be steadily climbing lets say from 30 volts and then all of a sudden will read like 3-12 volts for a split second then go back to where it was and continue to climb. Like its getting some AC voltage or something. I've tried some ulta fast diodes, 1n5408, and a FWBR externally and also have a 1n5408 on the winding internally and it still does it. It happens every 5 to 10 seconds or so. It just hiccups for a second and then continues on where it left off on the voltage climb. Even with a battery hooked up, the voltage will suddenly read 3.27 volts or something and then go back to battery voltage. Do you have any idea what going on there, or is my meter ready to take a crap again. I've only ruined 5 or so already in that last 2 years, lol.

Mark

Mark,

Bedini and I saw things like this all of the time. Our best explanation of it is that you are seeing an artifact of the digital meter's sampling rate, which intersects (and samples) the "chatter" sometimes, and other times does not. In any event, these types of signals are very hard on digital meters, when looked at directly. We eventually moved to looking at this stuff with a current probe connected to a fast digital scope. Even then, odd waves would move through the data stream that John believed were related to "gravity waves" because of their long period. I never did postulate an alternative explanation of the phenomena.

We got to the point where we just used analog meters in these cases, as they gave us the "average" readings that were reasonably accurate when checked against the area under the curve on a digital scope.

Peter

[Mark]

Matt

With your stock brush set up you must be using the commutators and brushes that are 180 degrees apart if you have an internal diode. If you used brushes and commutators that are 90 degrees apart you could remove the internal diode. Then your 2 output brushes would be 180 degrees out of phase. I wonder if that setup would be any better.

Pault

Looking forward to here some results on your set up.

Mark

[Mark]

Mark,

Bedini and I saw things like this all of the time. Our best explanation of it is that you are seeing an artifact of the digital meter's sampling rate, which is in phase with the "chatter" sometimes, and other times is not. In any event, these types of signals are very hard on digital meters, when looked at directly. We eventually moved to looking at this stuff with a current probe connected to a fast digital scope. Even then, odd waves would move through the data stream that John believed were related to "gravity waves" because of their long period. I never did postulate an alternative explanation of the phenomena.

We got to the point where we just used analog meters in these cases, as they gave us the "average" readings that were reasonably accurate when checked against the area under the curve on a digital scope.

Peter

Thanks for the heads up Peter. I wish I had a scope and knew how to use one.

One thing I'm concerned about is that when comparing the modified to the stock motor I'm not seeing any significant advantage like I expected. Matts setup without collecting the spike and collecting the generated output appears to be better. Your reflection on this would be appreciated. I'm wondering if a 6 brush set up would be better on the 4 pole motors. I havent started working on the 2 pole motor yet so maybe things will be different with that one. Don't know a lot to learn still.

Mark

[Peter Lindemann]

Off Topic

If this post isnt considered relevent to this thread then ill start a new one obviously, but i think it plays a part.

Peter, i recently re-watched your very enjoyable Electric Motor Secrets Video, however one thing seems to be in error as far as i can see.

Early on in the video you show a demonstration of 2 DC motors mechanically coupled so that the motor on the right is acting as a motor (and a generator inside )....and the motor on the left is acting only as a generator, it also has a volt meter across it.

4V is applied to the motor on the right and it draws around 3.0Amp, meanwhile the "generator" on the left via the meter is showing a generated voltage of around 3.2V.

Here is my problem, lets say the meter has an internal impedance of say 10M Ohm, this means that overall the "generator" is generating a voltage of 3.2V across a "load"(resistor) of 10 M Ohms. From this we can calculate the current flow..

I = 3.2 / 10,000,000 = 0.00000032 Amps

from this the power through the "load"

P = 3.2 * 0.00000032 = 0.000001024 Watts

youre overall assumption is that the CEMF is always around 3/4 of the applied voltage, in the above example this is true.......but now lets leave everything the same and measure using a different meter that has an internal impedance of 5 M Ohms..

we know the power through the load will be the same..so..

P = V^2 / R ...so V^2 = P * R = 0.000001024 * 5,000,000 = 5.12

so V^2 = 5.12 therefore V = 2.26 V on the meter

now the CEMF "appears" to be only just above half of the applied voltage and not 3/4.

in other words, it seems erroneous to me to simply stick a meter onto a DC motor(acting as a generator in this case) and from the measurement taken then simply say that the CEMF is 3/4 of the applied voltage.....since the voltage developed by the "generator" will be dependent on whatever "load"(the meter in this case) it has across it.

I.E a 10 M Ohm meter wil show a voltage of 3.2 V and a 5 M Ohm meter will show a voltage of 2.62 V.

If im in error in all this then id greatly appreciate someone pointing out where ive gone wrong.

Thanks

Rave154,

First, this is really OFF TOPIC for this thread. Second, you are missing the point, as the Back EMF is a constant function inside the motor and it is not related to how it is represented on any given meter. The "3/4ths" is not some "rule of thumb" that applies to CEMF in general, but only to the example shown, as evidenced by the meter readings. Third, this is a speculative exercise on your part. If you would really like some insight into this, you should repeat the experiment yourself and observe what happens on the bench.

The fact that the current moving through the generator both lights the light bulb (first energy manifestation) and activates the reverse motor torque (second energy manifestation) illustrates the point I am making, regardless of any meter readings.

Peter

PS Do not respond to this in this thread!!! Either start a new thread or post it in the first EMS thread.

[Matthew Jones]

Mark
I don't think that would work. Even with the arrangement your going to get input power coming in and going out briefly from the discharge side. Unless you use only one slot on the commutator, and that will lower the overall performance of the motor.

I think its better to just keep it separate. With the right timing mechanism in place the output can be stepped up and looped back to the front end easily. With little to no speed loss in the motor. This will dramatically lower the input.

What I have been thinking about is using is a bifiliar. 2 zig zag coils with a diode at the end. But the diode would be 180 out on both coils.
This might improve performance.

I have a blank rotor I am going to try it on sometime soon.

Matt

[Matthew Jones]

Also one more thing to add.
I tested (Not a good enough test though)a stock motor that is 24 volt 15.4 amp motor with the one I have rewound.

When I grab the shaft of the stock motor I can slow it down with my hand and make it draw about 12 amp at 24 volt.
The same pressure applied to my 72 volt model only draws a little over an amp.

So equal amount of work. 288 watts in the stock. 72 in the modified minus recovery.

Its not real good test and I am going to move to a pony break as soon as I can get my hands on the parts I need. But its nice to see this can work.

I can't wait to hook it up on my motorized Skateboard.

Matt

[Peter Lindemann]

Too Early to Compare

Thanks for the heads up Peter. I wish I had a scope and knew how to use one.

One thing I'm concerned about is that when comparing the modified to the stock motor I'm not seeing any significant advantage like I expected. Matt's setup without collecting the spike and collecting the generated output appears to be better. Your reflection on this would be appreciated. I'm wondering if a 6 brush set up would be better on the 4 pole motors. I haven't started working on the 2 pole motor yet so maybe things will be different with that one. Don't know a lot to learn still.

Mark

Mark,

No need for concern. You are still just "idling" your test set-up in the "high back EMF" zone, so performance ISN'T better. If fact, it is probably worse because you are building current limitation into the motor's operation.

Motors will ALWAYS rise to the speed where the back EMF reduces current input. When we are done with your mods, the motor may be capable of 12,000 rpm UNLOADED, but we will LOAD it to about 3000 rpm to "stay ahead" of the back EMF. Again, the goal is a GAIN in mechanical power, based on being able to apply high torque pulses at higher speeds than usual.

In the normal run mode, the motor has this seemingly "wonderful" self-regulating feature where the motor automatically draws more current when a load is applied. Your modifications are removing this operating feature. After your modifications, the only way to make the motor rise into the load is to raise the voltage. You can see this starting to happen with Matt's unit.

Don't lose sight of where we are going with this. Eventually, we want to run the motor on capacitor discharges, and the capacitors will be able to charge to higher and higher voltages the faster the system goes.

Hang in there!!!! You are on the right path.

Peter

[Peter Lindemann]

Looking Good

Also one more thing to add.
I tested (Not a good enough test though)a stock motor that is 24 volt 15.4 amp motor with the one I have rewound.

When I grab the shaft of the stock motor I can slow it down with my hand and make it draw about 12 amp at 24 volt.
The same pressure applied to my 72 volt model only draws a little over an amp.

So equal amount of work. 288 watts in the stock. 72 in the modified minus recovery.

Its not real good test and I am going to move to a pony break as soon as I can get my hands on the parts I need. But its nice to see this can work.

I can't wait to hook it up on my motorized Skateboard.

Matt

Matt,

This is a very encouraging report. Your Prony Brake idea is the right one. If you can quantify the mechanical power gain, you have all but proved the thesis.

If you remember, I show how to build a dynamometer (Prony Brake) in Electric Motor Secrets, Part One.

Keep up the great work.

Peter

[Matthew Jones]

While were on it any good recommendations for pony break system. I have been looking them over but I would like to review some more if possible.

Any helps appreciated.

Matt

[Mark]

Also one more thing to add.
I tested (Not a good enough test though)a stock motor that is 24 volt 15.4 amp motor with the one I have rewound.

When I grab the shaft of the stock motor I can slow it down with my hand and make it draw about 12 amp at 24 volt.
The same pressure applied to my 72 volt model only draws a little over an amp.

So equal amount of work. 288 watts in the stock. 72 in the modified minus recovery.

Its not real good test and I am going to move to a pony break as soon as I can get my hands on the parts I need. But its nice to see this can work.

I can't wait to hook it up on my motorized Skateboard.

Matt

I am getting totally different results than you Matt. My new stock 24 volt motor draws 900ma @ 24 volts and when I grab on to it I can only get the amps up to 2.25 before it burns my fingers in about 3 seconds. With my modified motor running at 48 volts I can only get it up to about 700ma. So both motors draw about twice as much. What kind of speed are you getting out of your modified motor at 48 volts?