Lockridge Device - Peter Lindemann

[mbrownn]

Matt said

"One thing I did last night was go to 60 volt. That doesn't work as well. Something must be happening internally because amperage use goes up. All the times I stepped the voltage up before the amps went down. So that might be the overload point."

Peter said

"This is WHY we want to run the motor on high voltage pulses and ultimately restrict the speed with an appropriate load, such as a generator that charges a capacitor."

So if I have this right, just below The speed where the amps increase we start to load the motor in a way that the speed remains constant. Easily done by using an alterneter as the load and varying its supply on the rotor.

The recovery is then fed into a capacitor placed between the source and the input of the motor to reduce input.

[n84dafun]

Brian

Have you run any amp draw tests yet with your 4 pulse setup?

Mark,

I haven't done any testing since I took those videos. In the video, I was running about 15V at 600mA, and up to 900mA when I shorted the recovery lines (without any diodes). I just glued the brush housing on the brush board so it doesn't wiggle around. Should be dry in 20 hours or so.

I did a stupid thing today and tried to get a waveform reading on my old ungrounded variac. Thinking that one side of the outlet plug hole was ground, like a DC source ground, and the other side was a hot AC line, I placed the ground of my scope probe on the left slot and SHAZAM!!! sparks flew, the fuse blew on the variac, and sent me jumping back a few feet. Luckily it just left a black soot mark on my thumb and didn't burn a finger or stop my heart. I wish I had my video cam running! This is a warning to me that this hobby can be fatal if not careful.

Brian

[Mark]

Mark,

I haven't done any testing since I took those videos. In the video, I was running about 15V at 600mA, and up to 900mA when I shorted the recovery lines (without any diodes). I just glued the brush housing on the brush board so it doesn't wiggle around. Should be dry in 20 hours or so.

I did a stupid thing today and tried to get a waveform reading on my old ungrounded variac. Thinking that one side of the outlet plug hole was ground, like a DC source ground, and the other side was a hot AC line, I placed the ground of my scope probe on the left slot and SHAZAM!!! sparks flew, the fuse blew on the variac, and sent me jumping back a few feet. Luckily it just left a black soot mark on my thumb and didn't burn a finger or stop my heart. I wish I had my video cam running! This is a warning to me that this hobby can be fatal if not careful.

Brian

LOL, Damn I hate that when that happens! Well at least you didn't let the smoke out.

I did a little testing on my new unmodified 24 volt motor. @12 volts draw is 700ma @24 volts 900ma and @36 volts 1amp. Rpm's are 1650, 3350, 5080 respectively. When comparing the modified motor to the unmodified motor my amp draw is actually higher and the power "seems" to be less (untested except using finger pressure, ouch). The modified rotor is 20 poles and the stock one is 16. The higher amp draw is most likely due to thicker wire, not enough turns and using 2 commutator sections (these are my thoughts).

[Matthew Jones]

......So if I have this right, just below The speed where the amps increase we start to load the motor in a way that the speed remains constant. Easily done by using an alternator as the load and varying its supply on the rotor.
The recovery is then fed into a capacitor placed between the source and the input of the motor to reduce input.

Most likely not. The output might be serialized with the output of the generator to achieve a high voltage, moderate amperage source. Then the potential difference between the output and the capacitor is used to drive the bulbs, while recovering energy.
This allows everything to stay in the system. Keeps the generator and motor from locking up from a big load.
Main goal might not be the recover, its most likely a high voltage real low amperage pulse to create alot of torque, but the recovery is going to be the key. It gonna need to be high enough to be able to add to the system.

One thing I have noticed is the amp draw while the recovery is on does go up, as expected. But the torque appears to almost double.
I am going to try to get a pony brake going and see the torque differences in real numbers.

Cheers
Matt

[rave154]

Electric Motor Secrets

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

[Mark]

More tests to report:

Rewound the 20 stator pole motor with 23awg wire with 200+ wraps.
Input 24 volts @ .375ma = 1090 rpm's
Input 36 volts @ .310ma = 1810 rpm's

With an input of 12 volts the motor only turned around 325 rpm's and the amp meter bounced too much to get a accurate reading.

So with smaller wire the amp draw and the speed were both reduced. I collected the spike in a same cap used before the the voltage was a lot higher.

What I found was bigger wire = more speed with the same voltage but higher amperage. I did some calculation on input watts divided by speed and noticed that when comparing the 2 wire sizes that the rpm's per watt were near equal. To clarify the speed was the same when using 8 watts of input with 20awg wire and 12 volts or 26awg wire with 24 volts. This ratio is not set in stone and may change depending on set ups.

Hope this info is helpful.

Mark

[pault]

I collected the spike in a same cap used before the the voltage was a lot higher.

How are you determining what size cap to use?

thanks
pt

[Mark]

How are you determining what size cap to use?

thanks
pt

No method, just using a low uf cap to get an idea of how big the back spike is.

[Matthew Jones]

You should try a higher voltage Mark. See if the amps find a point where they level out or go down.
Do you have an Internal Diode?

I have also been charging a cap. 120v 10000 uf and it immediatly shows 28 volt. But runs up to 36 volt real quik. Thats running a 48 volt system and using a bridge rectifier.

I still haven't moved my brush's or expanded the commutator.

This is showing more promise that I would have expected.

Matt

[pault]

P.A. motor info

The stock Princess Auto motor uses 18awg wire for the windings.

15 turns is about 90 inches of wire.

I haven't kept up with motor theory and I don't recognize how it's wound (lap? wave?), so I'm going to start with the assumption that one stock commutation energizes four 15-turn coils. I'll try 60 turns of 18awg...

pt

[Mark]

You should try a higher voltage Mark. See if the amps find a point where they level out or go down.
Do you have an Internal Diode?

I have also been charging a cap. 120v 10000 uf and it immediatly shows 28 volt. But runs up to 36 volt real quik. Thats running a 48 volt system and using a bridge rectifier.

I still haven't moved my brush's or expanded the commutator.

This is showing more promise that I would have expected.

Matt

I'll give that ago Matt. I wish I wouldn't have moved my brushes yet so I could have played some with the generator action like you have.

What kind of rpm's are you getting at 36 and 48 volts? I also noticed that with the 20awg wire I wasn't getting very big spikes and am wondering if not moving the brushes would cause much harm to them. What are your thoughts on this Matt. And how is your brush wear?

[pault]

First light

I wound the armature, but stopped after 30 turns of 18awg. That's about all that would fit.

It ran on a 12VDC slab for some seconds.

I could see, and smell, arc's through the entry hole for the leads (I didn't replace the grommet yet), so I quit, pending the addition of the 2nd set of brushes. Nothing seemed to be getting hot.

- To get it to start itself, I marked the shaft and positioned it so that the brushes were "on" before applying power. (It took me only one false no-start to figure this out ).

- Replacing the cowling (with the magnets glued in) was a pain. As soon as I got close, the magnets would suck the armature up and out of the brushes, and the brushes would snap shut. The best way to keep the brushes away from the shaft while re-inserting the armature seems to be by pulling the spring lever arm right out from the brush casing and pinning it to the back of the casing until the shaft is in place.

- The commutator assembly is offset from the armature such that when I positioned the coil directly in the middle of the magnets, the brushes touched two commutators each. I picked one set and went with them. This turned out to be the commutator two slots away from the coil. [This model has 10 slots].

- The 18awg was hard to work with. I unwound my work a few times before getting reasonably flat / tight windings. Had to pull hard when setting each winding in its slot. It still looks like it was hand-wound by someone who hasn't wound a motor in decades...

pt

[Mark]

You should try a higher voltage Mark. See if the amps find a point where they level out or go down.
Do you have an Internal Diode?

I have also been charging a cap. 120v 10000 uf and it immediatly shows 28 volt. But runs up to 36 volt real quik. Thats running a 48 volt system and using a bridge rectifier.

I still haven't moved my brush's or expanded the commutator.

This is showing more promise that I would have expected.

Matt

48 volts is the max I can run. At 60 volts the motor bogs down and the amps jump up. With 48 volts my 300uf cap would chaarge up to almost 100 volts. The amp draw of the motor @ 48 wolts was 450ma with the cap but if I hooked the back spike up to a 12 volt battery the input would jump up to 1 amp.

My other 2 motors arrived today. They are 12 volt, 2 pole motors. The rotors have 10 slots and the commutators are twice the size of the 24 volt motors and are very well constructed. Someone else had posted pictures of one a few pages back. The rotor slots are pretty wide and magnets are quite a bit larger then the 24 volt motor ones. The wire on the rotor now looks like 20awg to me. Adding 2 commutators will be the problem with this one because the boards aren't complete circles. It looks like I maybe able to cut one board and glue it to the top of the other. The commutators are pretty long and there should be enough clearance.

[Mark]

Hey Matt,

I was going back thru some of the posts and seen the one where you posted pictures with your commutators moved. Why haven't you tried to bolt that one on the motor or is the cover different?

[pault]

My other 2 motors arrived today. They are 12 volt, 2 pole motors. The rotors have 10 slots and the commutators are twice the size of the 24 volt motors and are very well constructed. Someone else had posted pictures of one a few pages back. The rotor slots are pretty wide and magnets are quite a bit larger then the 24 volt motor ones. The wire on the rotor now looks like 20awg to me. Adding 2 commutators will be the problem with this one because the boards aren't complete circles. It looks like I maybe able to cut one board and glue it to the top of the other. The commutators are pretty long and there should be enough clearance.

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. [Oh, I can choose the direction of rotation by choosing which lead is +ve and -ve.]

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.

I'd love to hear any other ideas.

pt