Lockridge Device - Peter Lindemann

[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

[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

[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.

[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]

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

[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

[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

[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).

[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

[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.

[pault]

Princess Auto motor update

Update regarding the "Princess Auto motor":

I managed to remove the varnished wire from the armature with fairly little effort and no heat.

I snipped the outermost coil at the commutator and just pulled the wire.

The varnish wasn't a big problem, but took a bit of pulling. I wound the wire onto a spool and used the spool to help with the leverage.

I found that the worst problem was with the blue glops. They were rock solid. I destroyed the coils that had blue glop, by cutting them and then pulling (hard).

I salvaged about half of the windings, and destroyed the other half.

Be careful not to put leverage on the armature itself - it is built with many layers of thin material that can be damaged in the process.

I counted 15 turns in each loop. The spec sheet says 14awg.

[There were 10 slots. The wire loops were 5 slots apart. The end of each loop was connected to adjacent commutator segments.]

The copper commutator connections are "crimped". I opened the crimp using needle nose pliers, grabbing the connector vertically and pulling gently backwards.

* The 14awg in the spec sheet refers to the lead wires, not necessarily the windings.
* Two coils are connected to each commutator segment. In fact the windings are composed of one continuous piece of wire which is connected to a commutator every 15 turns. It's not clear to me how many loops are fired on every commutator pair connection (2, 4?).
pt

[Matthew Jones]

Its 120 ft of wire. 3.33 ohms of resistance. Its not much wire really.

I didn't get to it tonight, the beer was tasty though. I'll let ya know tomorrow.

Cheers
Matt

[Mark]

240+ turns of 24 awg on the zig zag pattern. That means 1 turn equals a full pattern.

2 commutator spaces on a 16 pole rotor. But I am going to try 3 or 4 tonight. then I will not have to replace my recovery brush's.

48 volt so far showed the best results. But I am going higher after I fix the rotor.

Matt

240 turns, wow! That may make a big difference. With the 20 pole, the slots are not very big and I used 20 awg, I didn't count the turns but probably only had around 30. I just recieved a new motor I just ordered should be the same one you have. I also ordered 2 of the 2 pole motors, they should be here in a few days. I have some 24 awg but probably not enough to wrap that many turns. I also have some flat wire, 30 or 34 awg but I think thats too small.

Please keep us posted on your results when running 3 or 4 spaces Matt. Sure would make things a lot easier if we don't have to move the brushes.

[Matthew Jones]

Wanted everyone to know that I rewound my rotor back to the zig zag method to try and replicate the low amp draw Matt had. Running on 36 volts My amp draw while collecting the spike into a cap was around 1.2 amps. Pretty much the same as it was with winding 2 seperate coils. I'm not sure why my amp draw was 4 times higher than Matts. Could be my wire size, number of wraps, the differences in the rotor not really sure.

I'm curious to hear more about Matts setup after he moves his brushes to see if that changes his results.

240+ turns of 24 awg on the zig zag pattern. That means 1 turn equals a full pattern.

2 commutator spaces on a 16 pole rotor. But I am going to try 3 or 4 tonight. then I will not have to replace my recovery brush's.

48 volt so far showed the best results. But I am going higher after I fix the rotor.

Matt

[Mark]

Brian

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