Lockridge Device - Peter Lindemann

[Mark]

Sounds like an awesome motor Mark P. Is it a permanant magnet motor and if so do you know how many magnets are in it?

[Robbush]

They should work, how many magnets are in the case?

[Rl2003]

Just Two very large magnets. They are 4 inch's long and .625 thick. The ID of
the motor housing is 4.25 inch's. There is about a 1 inch gap on each side
between the magnets. It seems that there is a S and N facing in. The
cool thing is if I hold a 1" long neo (rod) magnet near the edge, as if you
where putting it into the motor case, I can twist the magnet around. If I put my
fingers with the magnet (tightly) into the middle of the case, it is very very hard to twist.
The field between the two magnets is very strong. Especially in the middle.
I will try to post some pictures tomorrow so you can see what I an trying to
describe.

Mark P.

[Rl2003]

I have a puzzling question for all you thinkers. These have been boxed
up for almost 50 years in storage, and yet the motor case is not magnetized???
Nothing steel sticks to the out side of the case. It's steel or iron because a
magnet will stick to it, but with those big magnets inside, one would think
there sould be some magnetizum to the case??
Anyway just a side thought.

Mark P.

[Matthew Jones]

You got a Ferrite/Ceramic magnet inside?
They don't saturate the iron in the case for one. You also have a condition in which one is canceling out the other. The flux that is traveling through the case is taking the shortest path to the opposite pole. That would be the surface of inside of the case down to the next magnet.

If for instance it was one magnet, you might see more magnetization around the perimeter of the magnet.

This is the same reason Bedini always uses Ceramics, they do not saturate the metal the point that the metal changes state, most of the time.

Matt

[Rl2003]

You got a Ferrite/Ceramic magnet inside?
They don't saturate the iron in the case for one. You also have a condition in which one is canceling out the other. The flux that is traveling through the case is taking the shortest path to the opposite pole. That would be the surface of inside of the case down to the next magnet.

If for instance it was one magnet, you might see more magnetization around the perimeter of the magnet.

This is the same reason Bedini always uses Ceramics, they do not saturate the metal the point that the metal changes state, most of the time.

Matt

Yes Matt, They are ceramic. Thanks for the explaination.

Mark

[Rl2003]

Here is a short video of that motor I have. It was easier that taking
a bunch of pictures. I think this will work well, as I could make the brushes
very narrow and the on time would be very short even at slower RPM's.
If you can see the commutators are long and narrow as well as the
brushes.

Mark

YouTube - VIDEO0016

[Robbush]

Mark,
Those might be a bit more difficult to work with as the first thing to to is pull all the wire off. I can say the motor I found came apart very easily, only two glue spots that broke off easily. I think you could wrap two slots next to each other and also bridge the commutator sections and that could work. Those are some big magnets in that motor.
Peace
rawbush

[Eric]

ok so i decided to set and learn how to run a prony brake test running my motor in stock mode to get some output numbers to compare with for when i modify the winding.

below is a picture of the setup and a table of results, the first time i tried to run a prony test awhile ago i used delron plastic to make a wheel of known circumference when i tried the test the plastic got too hot and melted to the leather strap didnt know it untill i hit the power again the wheel didnt let go of the strap and it ripped my 50 Newton spring scale apart. ooops. so i moved on to other things.. this time i used 28lb scales used to weigh fish and a piece of thick aluminum tubing and epoxied a piece of delron in the core and trimmed this down to a 6inch circuference bored and tapped the center to use the threads on the shaft. it spins really nice, no flex if i reef on it up and down with my hand, you have to spin the moter very slowly to see there is a very slight wobble in the wheel. after running a few brake tests the wobble hasnt grown. unfortunately i reached 28amps on the last test so i needed a bigger gauge. the 0 to 100 gauge i have appears to be giving me readings that dont match up with my smaller gauge so i will have to find anouther gauge.

i am wondering is there a point where useing this leather strap method might be unwise (ie will leather stretching yeald bad results) should i switch to a different setup like shown here de Prony brake - Wikipedia, the free encyclopedia useing a wooden arm to pull on a spring scale?

[Matthew Jones]

ok so i decided to set and learn how to run a prony brake test running my motor in stock mode to get some output numbers to compare with for when i modify the winding.

below is a picture of the setup and a table of results, the first time i tried to run a prony test awhile ago i used delron plastic to make a wheel of known circumference when i tried the test the plastic got too hot and melted to the leather strap didnt know it untill i hit the power again the wheel didnt let go of the strap and it ripped my 50 Newton spring scale apart. ooops. so i moved on to other things.. this time i used 28lb scales used to weigh fish and a piece of thick aluminum tubing and epoxied a piece of delron in the core and trimmed this down to a 6inch circuference bored and tapped the center to use the threads on the shaft. it spins really nice, no flex if i reef on it up and down with my hand, you have to spin the moter very slowly to see there is a very slight wobble in the wheel. after running a few brake tests the wobble hasnt grown. unfortunately i reached 28amps on the last test so i needed a bigger gauge. the 0 to 100 gauge i have appears to be giving me readings that dont match up with my smaller gauge so i will have to find anouther gauge.

i am wondering is there a point where useing this leather strap method might be unwise (ie will leather stretching yeald bad results) should i switch to a different setup like shown here de Prony brake - Wikipedia, the free encyclopedia useing a wooden arm to pull on a spring scale?

Ya use a 1 foot piece of wood and 1 scale. Makes it real easy to calculate. Tighten it down till you get a certain RPM, then you can do your calculations.
Maybe use a scale that measures in fractions of a pound and up to multiple pounds.


Matt

[theremart]

RE: Prony break.

ok so i decided to set and learn how to run a prony brake test running my motor in stock mode to get some output numbers to compare with for when i modify the winding.

below is a picture of the setup and a table of results, the first time i tried to run a prony test awhile ago i used delron plastic to make a wheel of known circumference when i tried the test the plastic got too hot and melted to the leather strap didnt know it untill i hit the power again the wheel didnt let go of the strap and it ripped my 50 Newton spring scale apart. ooops. so i moved on to other things.. this time i used 28lb scales used to weigh fish and a piece of thick aluminum tubing and epoxied a piece of delron in the core and trimmed this down to a 6inch circuference bored and tapped the center to use the threads on the shaft. it spins really nice, no flex if i reef on it up and down with my hand, you have to spin the moter very slowly to see there is a very slight wobble in the wheel. after running a few brake tests the wobble hasnt grown. unfortunately i reached 28amps on the last test so i needed a bigger gauge. the 0 to 100 gauge i have appears to be giving me readings that dont match up with my smaller gauge so i will have to find anouther gauge.

i am wondering is there a point where useing this leather strap method might be unwise (ie will leather stretching yeald bad results) should i switch to a different setup like shown here de Prony brake - Wikipedia, the free encyclopedia useing a wooden arm to pull on a spring scale?

Hi,

I also was thinking thru how can one figure out how accurate the prony brake was.. I believe the way to do is is to take a motor of known horse power and use that to calibrate the setup. As you mention there are many variables that need to be worked out and it looks like you are making good progress in your method.

But picking up an electric motor with X horse power that is in range of your measuring scales may be the way to go to get a ballpark idea if your measuring technique is accurate.

Just a thought.

[Eric]

Ya use a 1 foot piece of wood and 1 scale. Makes it real easy to calculate. Tighten it down till you get a certain RPM, then you can do your calculations.
Maybe use a scale that measures in fractions of a pound and up to multiple pounds.


Matt

how do we alter the math in calculating for the 1 foot arm to the scale are we adding it to the circumference of the wheel?

[dragon]

If you have a 1 ft arm and are measuring in lbs you simply multiply those together. The formula becomes...

ftlbs x rpm / 5252 = HP x 746 = watts
________
Electronic Cigarette

[Matthew Jones]

Dragon is right. Makes it real easy to determine the horsepower or watt output.

Matt

[pault]

Back-to-back test jig

I now have a back-to-back test jig - the modified 12V motor driving an unmodified motor of the same kind as a generator.

I'm running the unmodified motor unloaded and simply attaching an analogue voltmeter to its leads.

I'd appreciate any advice about the setup and the desired measurements.

I did a few quick test runs:

voltage in, current in, generated V in un-mod'ed motor, RPM
12.54V, 5.6A, 11v, 3333RPM
In a minute or so, the current dropped to 5A, then 4.7A

25.33V, 6A - had to stop to tighten a bolt

25.17V, 7.25A, 16V, 6,000 RPM
23.58V, 5.7A, 14V, 4,285 RPM (after 90 sec of running)
23.42V, 5.7A, ??, 3,750 RPM (after 4 minues of running).

I tried to swap a dead SLAB in on the 2nd pair of brushes and ran the back-to-back at 37.3V, but I saw sparks inside the motor, and stopped.

Advice would be appreciated.

If this looks like a dead end, I can wind another armature differently, since I've got a spare armature.

pt