Electric Motor Secrets

[Peter Lindemann]

Slow Down

Peter,

For my first post I would like ask you a very important question. I am finalizing my construction plans for an electric motor which is very closely related to your attraction motor. I have found that Silicon steel is very hard to come by, and when one can get it, after it has been properly prepared individuals of limited means cannot afford it. My question is, what over the counter sheet steel grade is best suited for these types of devices. High permeability and almost zero retentivity. Thanking you in advance.

Please forgive me if this was posted in the wrong area.


P.S.

I was looking forward to meeting you in Heidelberg Germany November 2006 at the 150 Tesla Conference. I was the guest of Walter Baumgartner. Jeanne Manning came in your place, one day I hope to meet you.


Regards

Dear Erfinder,

Before you go out and start substituting materials to save money, you really need to read this whole thread. A number of experimenters did a lot of work on models that failed because they started with the wrong materials. I do not recommend any substitutions for motor laminations. This material is the industry standard for these applications and works properly for our requirements. You are better off saving up your money and doing it right the first time, than cutting corners and working hard for months, only to end up with a model that doesn't work properly.

The Internet is full of bargains. Put your time into looking for a good deal on the right material.

Peter

[erfinder]

Dear Erfinder,
This material is the industry standard for these applications and works properly for our requirements.
Peter

This is what I was looking for. Thank you sir!


Regards

[ren]

To Erfinder,

I have been fascinated by your work and ideas in other forums, Im glad you found us here, and I hope you continue to visit and post!

Ren

[elias]

Some tests

Hi,

Thank you Peter, this means a lot to me.

I did some tests with higher voltage, here is the result:
Input: 42v, 550mA
Output: 6.7v, 1.2A
Running at around 7500 RPM

The recovered energy is more than 34% of the input used at 7500 RPM and the mechanical power is considerably strong at around 3000RPM (which draws about 1A), which is impossible to stop by holding the shaft.

But the input current increases when loading it to a lower speed. (due to the increase "on time" of the coil)

Some more test to be done tomorrow after I modify the circuit and try pulsing the coil with a function generator to find the optimum pulsing rate.

Elias

[Jetijs]

Elias, those are some good results
If you chop the ON pulses so that they are eaqual to the coils rise time, then you should get the best inpututput ratio. Do you have some current scope shots? If you have, then you can easily calculate the best pulse lenght
Thank you,
Jetijs

[Peter Lindemann]

Measuring the Output

Hi,

Thank you Peter, this means a lot to me.

I did some tests with higher voltage, here is the result:
Input: 42v, 550mA
Output: 6.7v, 1.2A
Running at around 7500 RPM

The recovered energy is more than 34% of the input used at 7500 RPM and the mechanical power is considerably strong at around 3000RPM (which draws about 1A), which is impossible to stop by holding the shaft.

But the input current increases when loading it to a lower speed. (due to the increase "on time" of the coil)

Some more test to be done tomorrow after I modify the circuit and try pulsing the coil with a function generator to find the optimum pulsing rate.

Elias

Elias,

How did you measure this output of 6.7 volts @ 1.2 amps? What is the load?

Peter

[elias]

Elias,

How did you measure this output of 6.7 volts @ 1.2 amps? What is the load?

Peter

Peter,

I have put a 6 volt battery at the charging end, and I was measuring the current into that battery, but I guess it is better to measure the pulse width by the scope, I would do some tests on the motor coil today with a function generator, and post the results.

I intend to connect the output of the hall device with a pull up resistor to the RESET pin of a 555 timer, and adjust the 555 chip to pulse the coil at the most efficient rate, so when the hall device comes on, the reset goes down and the timer sends pulses to the transistor base, to make the attraction cycle work, and when the hall device turns off the RESET pin pulls up and the timer would not send any pulses. First I am going to find the efficient pulsing rate with my function generator.

Regards
Elias

[elias]

More Tests

Hi,

Thought to share new tests:
This time I used a 220V, 60W lamp parallel with a 33uF capacitor on the output.
Around 6000RPM:
In: 49V, 0.52A, Out: 58V, 0.11A recovery: 34%

Around 3000RPM (loaded)
In: 45V, 1.2A, Out: 100V, 0.17A recovery: 30%

Just to mention that the motor seems to have a lot torque to it, and it is impossible to stop it by holding the shaft.

While pulsing independently, the maximum efficiency was at 205Hz, with 50% duty cycle:
In: 44V, 1.27A = 55.8W
Out: 130V, 0.18A = 23.4W
Recovery = 42%

Next, I'll use a 555 to pulse the coil at 200Hz.
It seems that different size capacitors can capture different amount of energy. I'll find this out later.

Elias

[Peter Lindemann]

Excellent Work

Hi,

Thought to share new tests:
This time I used a 220V, 60W lamp parallel with a 33uF capacitor on the output.
Around 6000RPM:
In: 49V, 0.52A, Out: 58V, 0.11A recovery: 34%

Around 3000RPM (loaded)
In: 45V, 1.2A, Out: 100V, 0.17A recovery: 30%

Just to mention that the motor seems to have a lot torque to it, and it is impossible to stop it by holding the shaft.

While pulsing independently, the maximum efficiency was at 205Hz, with 50% duty cycle:
In: 44V, 1.27A = 55.8W
Out: 130V, 0.18A = 23.4W
Recovery = 42%

Next, I'll use a 555 to pulse the coil at 200Hz.
It seems that different size capacitors can capture different amount of energy. I'll find this out later.

Elias

Elias,

Great work. I know everyone here would love to see the schematic of your circuit, and how you are using the hall effect device to modulate the 555 timer. 42% recovery still seems a little low. My GUESS is that the aluminum frame has some big eddy currents in it that soak up the rest of the recoverable power. This was always a problem in the reluctance generators until we went to plastic frames. The aluminum end plates act like "shorted turns" of a second output circuit. If this is true, then 42% may be as high as you can get for this model.

If you can't stop the shaft, you may have some good torque. I measured (as close as I could) the mechanical energy output of my little motor at about 34% with an air-gap of .021". Your air-gap of .015" is 28% smaller than mine (envy) . Your torque production should be above 42% mechanical efficiency, if my guessing is close.

This is excellent, over all, for a simple demonstrator of the principles involved in the system.

Keep up the great work!

Peter

[elias]

Peter,

I will post my schematic, after perfecting it ok?
Just wanted to ask why is maximizing conventional recovery so important? SSG never outputs more than 30-40% conventional energy, but it does output more when charging batteries. If we charge batteries with this system, we are way up unity, no?

Also, I think that I can increase the mechanical output of the motor, by welding the gaps of my rotor segments, and making them as one, do you recommend me doing this at a later time?

Thanks
Elias

[elias]

Scope Shots

Peter,

My scope shots show that at least 70% of the energy is being recovered, what do you think? The attached scope shot, has voltage divisions of 50 volts, and 1ms time scale. It shows the signal at the collector of my transistor. The negative pulse is the power pulse, and the positive pulse is the recovered pulse, going to a capacitor + 60W lamp, through a diode. The frequency of the pulses is 206Hz which means: 60*206/2 = 6180 RPM. The second shot shows the current changing in the coil (probe across a 1ohm resistor).

I used a 555 to chop my motor pulse into smaller pulses, and it was not very good at all, because the motor almost lost its self-regulating function, which made it rather easy to stop. So I removed the 555 from my circuit, which made my motor drop down in performance. Although my motor draws more under load, but it also recovers more.

I wonder if there is an easy way to feed the recovered energy back into the driving capacitor.

I would share some videos, and the schematic tomorrow.

Elias

[Peter Lindemann]

70% looks Good

Peter,

My scope shots show that at least 70% of the energy is being recovered, what do you think? The attached scope shot, has voltage divisions of 50 volts, and 1ms time scale. It shows the signal at the collector of my transistor. The negative pulse is the power pulse, and the positive pulse is the recovered pulse, going to a capacitor + 60W lamp, through a diode. The frequency of the pulses is 206Hz which means: 60*206/2 = 6180 RPM.

I used a 555 to chop my motor pulse into smaller pulses, and it was not very good at all, because the motor almost lost its self-regulating function, which made it rather easy to stop. So I removed the 555 from my circuit, which made my motor drop down in performance. Although my motor draws more under load, but it also recovers more.

I wonder if there is an easy way to feed the recovered energy back into the driving capacitor.

I would share some videos, and the schematic tomorrow.

Elias

Elias,

Great scope shot. By the "area under the curve" method, it looks like you do have about 70% recovery. That's pretty good. The width of the output pulse is so close to the width of the input pulse, you are approaching an optimum speed. If it will go faster, see what the scope shot looks like at between 7000 and 7500 RPM. Somewhere in there, you should have maximum power AND maximum electrical return. This is the same speed range I calculated my motor would maximize its electrical recovery.

Your motor is probably OU already if your mechanical energy production is over 40%. Unfortunately, without a separate output winding, there is no way I know of to put the recovered energy back to the front of the circuit. It's one of the drawbacks of modifying an off-the-shelf motor.

Great work. Thanks for showing everybody that it is pretty easy to get this far with it!

Peter

[elias]

A Video

Hi,

Here is a short video,which shows the motor running with recovering energy to a 60W light bulb.

YouTube - Lindemann attraction motor test

Elias

[elias]

The Schematic

Hello everyone,

Here is the schematic I am currently using for my motor.
When the hall device gets activated it turns Q1 on and makes MJ15022 activate the coil. When the hall device turns off, Q2 turns off, and Q1 turns on, which makes MJ15012 turn off quickly, by discharging the base capacitance of it.

EDIT:
A resistor (about 1k-5k) must be placed, between the Zener diode and the hall effect sensor output, which I forgot to add.

Elias

[elias]

Increasing Motor Torque

GREAT WORK!!!!
It's nice to SEE the evolution of you're work.
Do you plan to welded the gap of you're rotor still???
Happy you have share it with us!!!

peper10

Thanks Alain,

Lets see if Peter recommend me to do this. But it seems that if I weld the gaps between my rotor segments, the amount of iron being attracted would increase thus increasing the motor torque. Currently it has a lot power at around 3000 RPM.

I wonder if I use a 30:1 gearbox, to convert the speed of it to more torque power, it may be able to drive a bicycle for me.

My motor is using around 28W at 6000, and 51W, while loaded at 3000 RPM. I can't hold it down to 3000 RPM more than a few seconds, by gripping my hand tightly to the shaft. It also recovers more under load.

Elias