Lockridge Device - Peter Lindemann

[tommy]

Such great information!

I've spent the last few days reading every post in the forum on the lockridge device and wow what a lot of information. Hearing diode here and triad there, it became overwhelming and confusing. I have watched both of Peters Electric Motor Secrets videos and, as many of you, are very enlightened by his observations. But you guys are way far ahead of me on electric motors and design and construction.

For education of myself and so people can easily pick up at the best practice scenario should they want to join in the research, may I suggest a file section that is moderated by senior members that details, one and only one, best practice motor for this topic? Then as better ways of accomplishing the goal is achieved, it is reviewed by senior members and if appropriate, replaces the current design. Again, this would ensure that newbies are starting from the best design.

Just a thought and great work!

Thanks

[Mark]

Hi Tommy

There are all different levels of knowledge, skill and expertise on most of the threads here. What you suggest is a good idea and may happen down the road. We're just getting started actually and are still trying to determine which particular motor, wire, voltage, etc. to use. So far there are only a few members reporting on their progress and we are still gathering which methods work best.

If you read over the last 5-10 pages again you'll be able to get a better understanding of who's doing what. You could purchase one of the motors that have been talked about (there are links posted) and join in or wait until there is a little more progress. If you read thru the posts, look at the pictures and view the videos a few times you'll get a better grasp of things.

Things should start to take shape in the next couple of weeks. My advise if your kind of lost right now is keep going over the posts and try to learn as much as possible before getting started.

Mark

[n84dafun]

Rotor Mishap

I haven't been able to do any more testing after the rotor in my motor malfunctioned. Also, I've been busy trying to catch up in my paper work, since I fell behind playing too much with my motor.

I've been able to set up my motor so that it pulses twice per revolution using a couple diodes in the rotor. It's similar to what I drew earlier, but works with the power brushes at 90 degrees apart. The motor runs well, but the heavy duty diodes (1kV, 3A) were fairly big and caused imbalance and vibrations. I tried to balance things out by soldering a "dummy" diode on one of the unused commutators. However, the centrifugal force from applying 72V from my VariAC/FWBR/FatCap dislodged the dummy diode from its place and caused havoc inside the motor.

There was also the problem with the wires coming off the windings at the rotor's edge and coming into contact with the magnets, causing it to flatten and break. It's a good idea to secure those wires by placing a piece of material like the bamboo stick that was originally securing the wires on the rotor. No wonder they put lot's of varnish on the wires, otherwise the wires would probably fly off from the spin force.

I had another short circuit incident with my Variac again when running the motor with it after I placed the probes on the output leads of the motor. I thought I learned my lesson the first time. Anyways, it caused a big spark inside my motor and upon inspection saw what damage unprotected commutators could incur at high voltage and no recovery brushes for protection.

I think I like my 4 pulse per revolution configuration the best because it doesn't use any bulky diodes and it is well balanced. Since I have a 20 pole rotor, and there are 4 pulses per rev, that means the duty cycle is 20%. Hopefully that's good enough to allow for cooling between pulses. I think Peter mentioned a 10% duty cycle on one of his posts.

Another concern I have is that the current flow through the windings alternates direction every quarter turn, whereas the 2 pulse setup pulses only one direction through the windings per 180 degrees. In both cases, I noticed negative and positive spikes on the scope, which is strange because I thought it would only give unidirectional spikes on the 2 pulse setup, since current only flows in only one direction through the coil on every pulse.

Once I rewind the rotor I can start testing again.

Brian

[woopy]

some diagrams for my comprehension

Matt thank's a lot for the braking test-

I don't see the difference between a pulse motor with brushes or with Any electronic switching.
So far i see , the pulse duration is depending on the length of the contact between the brush and the collector section or the length of the trigger magnet for a Hall sensor.
So if the length of the collector section or the trigger magnet is let's say10 degrees of the revolution . the pulse should be the same. Of course if the electronic circuitry is able to deliver the full power of the source power supply, as a brush does.

So my experiments lead me to the diagram here under.

On the left it is Peter Lindemann graph from his DVD
I understand that this graph is for a DC motor with brushes where each brush is always in contact or with 1 collector section or bridging 2 collector sections. so the power from the source is steadily apply to the rotor windings on all the 360 degrees of rotation.
So on the scope shot you see a steady line of the voltage and in the yellow part is the space for the BEMF to develop depending of speed.And as you can see this space is very large.

On the right graph it is my expectation so far
I understand that the brush is in contact with only 1 collector section per revolution. So it does not bridge on other section. So only one winding is fired per revolution, and this winding gives all the power.
Further more if this winding is of large wire section , it will be able to conduct strong current (torque) and as it has low impedence it will also generate low counter voltage so the place (yellow) is very small for the develloping of the BEMF.
So as Peter explain in the DVD we need winding of very low resistance to accept very high current pulsed once per revolution, to get strong mono-torque to spin the flywheel.
Finally if we use a cap to pulse the motor . the distance between the pulse is time to recharge the cap. So if you pulse more than 1 time per revolution you will have less time to recharge the cap and you will have more space for the BEMF to develop.

The problem with this one pulse motor is that it does not self start, or if you place collector section under the brush and you apply the power, the amperage will be huge, that is why i started the graph not at zero speed.

This my understanding and please don't hesitate to correct me if i miss something

Hope this helps

good luck at all

Laurent

[Matthew Jones]

Somthing NEW!!

Woopy
You've got me stumped, sorry.

So what did I learn today. I have spent the last 3 days trying to get a bifiliar version running, No success.
But I have tried several other things to increase the power on separate rotor but kept running into problems blowing diodes and very rough runs.

The whole time I was under the assumption that the ZIG ZAG pattern was pushing my rotor.
NOPE!!!!
Its a puller.

I went to reinstall my original rotor and noticed that I had set the commutator expansion ahead of the aligned slot, not behind.
So to expand the commutator I have to set ahead.

Now it may just be my rotor (I don't think so). I may have screwed up somehow, but just incase I wanted to let other know. If your getting hard bucking/cauging and slow speed well then you know what to try.

Cheers
Matt

[rosehillworks]

Matt When you say "expansion" are you bridging commutator sections or are you just moving the place that the coil is connected to the commutator ?

[Mark]

Matt When you say "expansion" are you bridging commutator sections or are you just moving the place that the coil is connected to the commutator ?

Rosehill

We're "bridging" 2 sections together to get a longer duration and more current into the coil.

[rosehillworks]

Mark Thank you for your answer. I was just making sure that I understood Matt right

[citfta]

PWM Control?

I have been thinking about what we are trying to accomplish here and have some ideas I want to throw out for your consideration. We want to use the most efficient motor we can come up with for our drive and we want to be able to control our output. Or at least be able to get a stable output. One of the most efficient gasoline engines made was the old hit and miss engines. They were huge because of the massive flywheel which they had to keep spinning. They were also very efficient. There are reports of them running all day long on a gallon of gasoline while producing 5 hp or so. So the idea of using a large flywheel to increase efficiency seems to be proved by real life. If you remember the hit or miss engine would fire for a time or two and then coast for several strokes of the piston before firing again. Almost exactly what we want our motor to do.

If we modify our motor to only have one or two pulses per revolution how are we going to control our output? If our input current is high enough to get the motor up to a speed that will turn our generator fast enough to produce an output that will keep the motor running what will prevent the motor from accelerating beyond that speed? I suspect in the original Lockridge device the 300 watt bulbs played a part in the self regulation of the device. As the bulbs get brighter from a higher voltage the resistance of the bulbs will also increase causing a drop in voltage to the cap and thus a slowing of the motor. I think this may have been difficult to get balanced out and probably had to be redone each time a bulb burned out.

With a fixed pulse width the only way to control the motor speed is by varying the voltage applied to the motor. If we use some of our modern technology available to us we can control the motor by varying the pulse width instead of the voltage. Even the little Picaxe 18X has a PWM output which could be used to drive a mosfet motor circuit. If we use a 12 volt DC motor as was first suggested by Peter then we could drive it with high voltage and high current to give us the torque we need and still have control of our speed. Another advantage of the 12 volt starter motor is that it is shunt wound which means when we turn off the current to the motor there is no back EMF.

Using the ADC input to the Picaxe 18X we can monitor the output of our generator and use that info to control the PWM signal for our motor. This means we would only be applying just enough power to our motor to keep the flywheel spinning at the right speed for our generator. Another advantage is we can now leave the armature unmodified and use all the commutator segments instead of only a couple of them.

Please feel free to point out any errors you see in my thinking.

Carroll

[Matthew Jones]

Matt When you say "expansion" are you bridging commutator sections or are you just moving the place that the coil is connected to the commutator ?

Marks right..

....Please feel free to point out any errors you see in my thinking.
Carroll

No problems with your thinking outside the fact that we have to get that far first. Most likely the original made really high voltage in the generator then stepped it down between the potential from the generator to the potential in capacitor, which the motor was running off of.
So you would be burning power all the while no matter what. Most likely the runaway condition is pretty far fetched thing to look at, but then again it may not be. Gotta get there to find out.

Matt

[Peter Lindemann]

Excellent!!

Matt thank's a lot for the braking test-

I don't see the difference between a pulse motor with brushes or with Any electronic switching.
So far i see , the pulse duration is depending on the length of the contact between the brush and the collector section or the length of the trigger magnet for a Hall sensor.
So if the length of the collector section or the trigger magnet is let's say10 degrees of the revolution . the pulse should be the same. Of course if the electronic circuitry is able to deliver the full power of the source power supply, as a brush does.

So my experiments lead me to the diagram here under.

On the left it is Peter Lindemann graph from his DVD
I understand that this graph is for a DC motor with brushes where each brush is always in contact or with 1 collector section or bridging 2 collector sections. so the power from the source is steadily apply to the rotor windings on all the 360 degrees of rotation.
So on the scope shot you see a steady line of the voltage and in the yellow part is the space for the BEMF to develop depending of speed.And as you can see this space is very large.

On the right graph it is my expectation so far
I understand that the brush is in contact with only 1 collector section per revolution. So it does not bridge on other section. So only one winding is fired per revolution, and this winding gives all the power.
Further more if this winding is of large wire section , it will be able to conduct strong current (torque) and as it has low impedence it will also generate low counter voltage so the place (yellow) is very small for the develloping of the BEMF.
So as Peter explain in the DVD we need winding of very low resistance to accept very high current pulsed once per revolution, to get strong mono-torque to spin the flywheel.
Finally if we use a cap to pulse the motor . the distance between the pulse is time to recharge the cap. So if you pulse more than 1 time per revolution you will have less time to recharge the cap and you will have more space for the BEMF to develop.

The problem with this one pulse motor is that it does not self start, or if you place collector section under the brush and you apply the power, the amperage will be huge, that is why i started the graph not at zero speed.

This my understanding and please don't hesitate to correct me if i miss something

Hope this helps

good luck at all

Laurent

Woopy,

I think you understand it really well!! Just relax your understanding and look at the relationships. Right now, we are just looking at running in "pulse mode" at about 3 times normal voltage, while trying to protect the commutator from arc damage and the rotor winding from over heating. Matt's test motor with only one power pulse per revolution is showing significant power at higher speeds, so this is an indication that the "theory" is correct.

By adding a little bit more mass (flywheel) the performance may improve, especially under a pulsed load, like a generator charging a cap.

Peter

[Peter Lindemann]

Issues with PWM Control

I have been thinking about what we are trying to accomplish here and have some ideas I want to throw out for your consideration. We want to use the most efficient motor we can come up with for our drive and we want to be able to control our output. Or at least be able to get a stable output. One of the most efficient gasoline engines made was the old hit and miss engines. They were huge because of the massive flywheel which they had to keep spinning. They were also very efficient. There are reports of them running all day long on a gallon of gasoline while producing 5 hp or so. So the idea of using a large flywheel to increase efficiency seems to be proved by real life. If you remember the hit or miss engine would fire for a time or two and then coast for several strokes of the piston before firing again. Almost exactly what we want our motor to do.

If we modify our motor to only have one or two pulses per revolution how are we going to control our output? If our input current is high enough to get the motor up to a speed that will turn our generator fast enough to produce an output that will keep the motor running what will prevent the motor from accelerating beyond that speed? I suspect in the original Lockridge device the 300 watt bulbs played a part in the self regulation of the device. As the bulbs get brighter from a higher voltage the resistance of the bulbs will also increase causing a drop in voltage to the cap and thus a slowing of the motor. I think this may have been difficult to get balanced out and probably had to be redone each time a bulb burned out.

With a fixed pulse width the only way to control the motor speed is by varying the voltage applied to the motor. If we use some of our modern technology available to us we can control the motor by varying the pulse width instead of the voltage. Even the little Picaxe 18X has a PWM output which could be used to drive a mosfet motor circuit. If we use a 12 volt DC motor as was first suggested by Peter then we could drive it with high voltage and high current to give us the torque we need and still have control of our speed. Another advantage of the 12 volt starter motor is that it is shunt wound which means when we turn off the current to the motor there is no back EMF.

Using the ADC input to the Picaxe 18X we can monitor the output of our generator and use that info to control the PWM signal for our motor. This means we would only be applying just enough power to our motor to keep the flywheel spinning at the right speed for our generator. Another advantage is we can now leave the armature unmodified and use all the commutator segments instead of only a couple of them.

Please feel free to point out any errors you see in my thinking.

Carroll

Carroll,

All of your thinking about this is excellent. The only issue I see is, if you can make the pulse width shorter or longer, how do you manage the recovery pulse at the different timing places on the commutator? In general, I think you are just getting a little ahead of the situation and are looking for a complex solution to a simple problem.

My current goal is to see if this can be solved like Lockridge did it, with brushes and commutators. If this can be done, and it looks very promising right now, then we can evolve a simple set of parameters for modifying motors for producing mechanical energy at a rate higher than 746 watts = 1 horsepower. If this thread can prove out a way to produce 1 HP for 300 watts or less, then the self-powered home generator is right around the corner.

That is my focus for the near term.

Peter

[Mark]

Peter

From my understanding of the last few posts It would be better to use 20 awg instead of the 26 awg I have currently, is this correct? I also have 18awg should I use this? What are your thoughts of running a quad filler 26awg all in Parallel?

[Matthew Jones]

Mark
your probably right in wanting to use a larger wire, the problems come in with the setup we are using.
If your inrush current in the beginning exceeds the diode surge then your not going to keep a diode alive long enough to enjoy the extra power.

So you have 3 solutions. A soft start type setup, or use smaller wire to ensure some resistance, or larger diodes.

A larger diode seems the way to go, but it got has got to fit onto the rotor.

Also there is one other thing that I have been noticing in mine. Lower wire resistance is a lower speed. I rewound my rotor with 24 same as the first one but did it with less wire. I wanted the resistance of the wire to be 2 ohm. But the speed is slower.
You said earlier (I think) that you wound with 26 and you were getting speeds in excess of 4000 rpm with 60 volt.
So this is an avenue that need to be explored. At some point the size of wire will reduce the overall performance but it may be a balancing act to get just the right performance out of the given setup so that we get the most power from the motor we are using.

I don't know if you are still running the 26 awg or not but I would encourage you to at least note the Ohms of resistance on the wire or the wire length so that resistance can be calculated.
as we figure out a standard performance these things are going to grow more important.

Cheers
Matt

[Matthew Jones]

Got It!!!

So after all mayhem. And figure out the motor was puller not pusher I tried 3 commutator spots.
5200 rpms from 72 volt .6 amp after start up. 2 ohms of resistance on the wire.

Now its doing something.

Best of all its stepping up the output voltage really nice and filling the 4700 UF cap to 92 volt close to instantly and not growing higher. That means its at the perfect point for stepping up.

If your using the razor scooter motor and you want full run down on everything let me know and I'll put it together.

Matt