Electric Motor Secrets

[Peter Lindemann]

Moving On

Steven, glad to hear form you
If I understood you correctly, then what you are suggesting is that one should use two switches, one on the positive side of the coil and other on the negative side. Then you must switch them on simultaniously and let the coil get the core magnetized, and at the end of this cycle, you need to switch both switches OFF at the same time? In my circuit There is only one (negative) side of the coil switched off and on, the other (positive) side is always connected to battery positive. Did I understood correctly?

Peter, if there is nothing I can do about my current motor, then I would like to go on with a simple induction motor startor core as my startor, just like Steven did, this has may advantages, first of all, the core material best suited for this purpose, there is a bigger area of attraction, the rotor wont move on its inertia at any time, because there will constanly be an attraction force. Also the startor core will be already perfect and I would not need to do any machining work on it. All I need will be only a rotor, and it is much easier to cut the rotor to the diameter needed to fit the startor, than to machine both out of nothing. I think I could make the rotor with a silicon steel lamination core since lighty kindly ofered to send me some silicon steel plates. Also since I need these plates only for my rotor, I wont need very much material for this compared to my current design. The wiring will be a pain in the ass, but all in all this design should be easier for me to make with the tools I have
What do you think about this?
Thanks,
Jetijs

Jetijs,

I agree. The design you built I had only proposed as a "stylized design" to show the relationships of the rotor and electromagnet. The design works, as you have seen, but is not the best for high power outputs. It's a great little demonstrator design.

The "notched drum" rotor, like Steven has shown, is going to produce a much more powerful motor. Before you try and build something along these lines, I would like Steven to tell us how his motor works.

Personally, I believe his pole pieces are a little too close together. Unlike a standard "Switched Reluctance Motor", this motor has to breathe. The field must have time to grow to maximum and decay to zero before the next cycle starts. The field must be completely gone for the rotor pole face to slide easily away from the stator pole or the speed of the motor will be restricted. There must also be sufficient space between the poles to prevent a forward attraction force from being partially negated by a reverse attraction force because the features of the physical geometry are too close together. As you can see on my little YouTube films, the test motor has no speed restrictions because there is plenty of time in-between attraction cycles. Your current motor was starting to show many of the right performance characteristics, in spite of the unfavorable magnetic behavior of your rotor and stator.

Since we both want you to build a successful motor, if we are going to abandon your current set-up, let's take all the time necessary to discuss motor operation theory and materials performance so that the next model you build has no hidden problems that show up after all the work is done.

So, Steven,....moment of truth.....what is going on with your motor?

Peter

[Jetijs]

Steven, glad to hear form you
If I understood you correctly, then what you are suggesting is that one should use two switches, one on the positive side of the coil and other on the negative side. Then you must switch them on simultaniously and let the coil get the core magnetized, and at the end of this cycle, you need to switch both switches OFF at the same time? In my circuit There is only one (negative) side of the coil switched off and on, the other (positive) side is always connected to battery positive. Did I understood correctly?

Peter, if there is nothing I can do about my current motor, then I would like to go on with a simple induction motor startor core as my startor, just like Steven did, this has may advantages, first of all, the core material best suited for this purpose, there is a bigger area of attraction, the rotor wont move on its inertia at any time, because there will constanly be an attraction force. Also the startor core will be already perfect and I would not need to do any machining work on it. All I need will be only a rotor, and it is much easier to cut the rotor to the diameter needed to fit the startor, than to machine both out of nothing. I think I could make the rotor with a silicon steel lamination core since lighty kindly ofered to send me some silicon steel plates. Also since I need these plates only for my rotor, I wont need very much material for this compared to my current design. The wiring will be a pain in the ass, but all in all this design should be easier for me to make with the tools I have
What do you think about this?
Thanks,
Jetijs

[Peter Lindemann]

How is your motor?

Lost of good experiments going on there lately!
But it might be time to move onto the more 'big boys' capture techniques.

You need to pulse both the pos rail and neg rail together.
There is a lot to this but to put it simply you have much limitations in how you are going to collect this energy.

Quick example.
Imagine this energy is a compressed spring, it is supported at one end by a red bracket and supported at the other end by a green bracket. Well if you are going to suddenly release its compression only at the green end, you have still got pressure at the red end as the spring keeps expanding. Ok, now lets suddenly remove both the green and red end together, there is no more pressure in our supporting frame which means the system is completely free and isolated from what the spring is doing. Mechanical and electrical all have the same effects.

(Side note: The purposed technique is not mine but from a well respected engineer I work with)
Steven

Steven,

Thanks for the two-sided switch idea. John Bedini has used a similar circuit for years, developed by his late friend, Ron Cole.

So, have you finished and tested the motor you built and posted photos of earlier in the forum? We are all very interested to know..........whatever you are willing to share.

Peter

[Peter Lindemann]

Core Material

elias,
yes I tried various frequencies with the 555 timer. I think, that the optimum frequency sweetspot is somewhere around where the pulse lenght is eaqual to the current rise time in the coil and that varies with different coils. I should get a function generator for these tests, because it is hard to adjust the frequrncy correctly with the 555 timer.

Peter,
are there any more tests you want me to do before I move on with a different aporach? Because with all the tests I have made, it does not look like that the problem with a low recovery is in the transistors, timing or frequency, it must be in the core material. If there is nothing I can do about this design anymore, then I have some other ideas
Thanks,
Jetijs

Jetijs,

We started this investigation with the assumption that the problem was the core material. I agree with you, that the tests you have run seem to have eliminated the other possible factors. Its your project, so do what you believe is best. I have no other suggestions at this point, other than replace your core and rotor material with something that behaves better magnetically.

Peter

[nali2001]

Back spike capture

Lost of good experiments going on there lately!
But it might be time to move onto the more 'big boys' capture techniques.

You need to pulse both the pos rail and neg rail together.
There is a lot to this but to put it simply you have much limitations in how you are going to collect this energy.

Quick example.
Imagine this energy is a compressed spring, it is supported at one end by a red bracket and supported at the other end by a green bracket. Well if you are going to suddenly release its compression only at the green end, you have still got pressure at the red end as the spring keeps expanding. Ok, now lets suddenly remove both the green and red end together, there is no more pressure in our supporting frame which means the system is completely free and isolated from what the spring is doing. Mechanical and electrical all have the same effects.

(Side note: The purposed technique is not mine but from a well respected engineer I work with)
Steven

[Jetijs]

elias,
yes I tried various frequencies with the 555 timer. I think, that the optimum frequency sweetspot is somewhere around where the pulse lenght is eaqual to the current rise time in the coil and that varies with different coils. I should get a function generator for these tests, because it is hard to adjust the frequrncy correctly with the 555 timer.

Peter,
are there any more tests you want me to do before I move on with a different aporach? Because with all the tests I have made, it does not look like that the problem with a low recovery is in the transistors, timing or frequency, it must be in the core material. If there is nothing I can do about this design anymore, then I have some other ideas
Thanks,
Jetijs

[Peter Lindemann]

Great Work

Yes and that's nice, but you didn't mention the frequency at which you pulsed your coil? My test data shows that there is a frequency for any coil that the efficiency gets maximized. Have you attempted to adjust the frequency of your pulsing? I have been able to get about 80% back with those coils, but maybe larger coils don't put back as smaller ones do. I'll do more experiments with different coils and see what happens.

Elias,

Thanks for running these tests. I have been saying that I thought 80% recovery was both possible and the goal of this project. If the motor can recover 80% of its input electrical energy AND produce 80% mechanical energy at the shaft by careful timing and small air-gap, then the motor should be able to operate with a COP=4.

Your tests show that 80% electrical recovery is possible with proper switching.

Thanks again,

Peter

[elias]

Are you talking about the motor I am working on? If so, then you have missed, that we already have an independent frequency of the pulses regardless of the RPM's of the motor. The switching is done by a 555 timer.

Yes and that's nice, but you didn't mention the frequency at which you pulsed your coil? My test data shows that there is a frequency for any coil that the efficiency gets maximized. Have you attempted to adjust the frequency of your pulsing? I have been able to get about 80% back with those coils, but maybe larger coils don't put back as smaller ones do. I'll do more experiments with different coils and see what happens.

[Jetijs]

Maybe we can design a system which can stabilize the frequency of the pulses independently from the RPM of the motor. increasing the input voltage, increases the recovered energy a bit.

Regards
Elias

Are you talking about the motor I am working on? If so, then you have missed, that we already have an independent frequency of the pulses regardless of the RPM's of the motor. The switching is done by a 555 timer.

Ok, I have done some tests today. I used my motor circuit to pulse the coil with a welding rod core. I made these tests with 5 different frequencies. I used two 12v batteries in series (24V) on the input. In the first test I used a 24V battery in the output and pulsed the circuit with one 2n3055 transistor to get the basic results so that I can compare the with other tests. The switching circuit with the 555 timer and the optotrigger consumed 0.09A, that must be taken into account. For the second test I used the MJL21194 transistor soldered on the same base plate parallel to the 2n3055 transistors. This time the switching current was 0.11A, because the PNP transistor now had to switch four transistors instead of three. Basically I got a little bit worse results compared to the 2n3055 transistor, bat I think that this is because now the circuit had to open and close four transistors in parallel thus consuming more current. After all both transistors are working just as good and we can safely say, that the problem is not th the transistors used. In test number 3 I used a light bulb in the output and the 2n3055 for switching. This time I got lower voltages and overall efficiency. And in the last test I attached a 10000uF cap in parallel of the bulb in the output, this increased the efficiency a little bit. Here are the results:
Test1

Test2

Test3

Test4


Any comments, suggestions?
Thanks,
Jetijs

[elias]

Another experiment

Hi

I played with the function generator a bit and found something interesting while connecting a lamp to the output along with a capacitor. See the attached circuit. There is a sweet spot for the minimum current drawn from the battery depending on the coil used. it is somewhat a bell-shaped curve. I experimented with the same coil and the result was interesting as it provided minimum current (29mA) to the inductor at about 28KHz and it increased when either increasing the frequency or decreasing it. In my setup I had:
Vin = 12V, Iin = 29mA
Vout = 10.20V, Iout = 27.5mA

The data above yields a recovery of about 80% of the input and it seems promising.
But when using capacitors only as the previous experiment I did at 5KHz, but now at 28KHz 50% duty cycle, I did not get more than 6 volts on the output capacitor. It seems also that lower frequencies with less duty cycle are better than higher frequencies with more duty cycle.

When the input voltage was 18 volts the minimum current drawn from the battery was at 31.5KHz:
Vin = 18.2V, Iin= 38mA
Vout = 16.36V, Iout = 35mA
In this case the recovered energy was about 81% of the input.

I experimented with a larger coil and that one gave me 76% efficiency at its sweet spot which was 2KHz.
In all of these experiments I used a duty cycle of 50%.

In conclusion I have to say that the motor seems to be able to recover the most in a certain RPM, or certain amount of pulses per second. Maybe we can design a system which can stabilize the frequency of the pulses independently from the RPM of the motor. increasing the input voltage, increases the recovered energy a bit.

Regards
Elias

[elias]

My test about the amount of recovery possible

Hi Jetijs,

I did an experiment to see how much output I could get out of pulsing a coil. The picture of the coil used is attached. It is pretty small (about 1cm in length). Probably it is about 5-10mH or less. Its core is about 1mm in diameter and is apparently made of ferrite.

For this purpose I used a 10,000uF capacitor for the input and a 10,000uF capacitor for the output, across the diode. I charged C1 to 12 volts and by pulsing it with an approximately 20% duty cycle at 5KHz I got the output capacitor charged to about 9.15 volts, while some charge was remained on the input capacitor at the end (about 0.5 volts). So I concluded that the efficiency of my pulsing system is about (9.15/12)^2 = 58%. Note that as the charge on the capacitor decreases the spike gets lower in amplitude and reduces the charging effect. I used a 900v FS7SM MOSFET and a square-wave signal generator for this purpose.

Hope this helps ...

Elias

[Peter Lindemann]

Welcome, Stefan

Hi Jetijs,
is your stator iron core solid iron or
laminated iron ?
Maybe eddy currents play a major role here,
that you can only get 24% back out ?
Also , did you see, how much you already are in saturation
in your BH curve of the iron core ?

Peter, is it better to drive the iron into saturation
or not ?
Also it probably depends a lot what kind of
core material you are using.
A low hysteresis metgals alloy would probably be much
better than just iron...
Maybe you also have too much hysteresis losses at the moment.

Regards, Stefan.

Stefan,

Since we are trying to recover the maximum energy from the collapse of the magnetic field, keeping the iron below saturation is best.

Also, you are probably right that low hysteresis materials like MetGlas would work the best in a motor like this. But right now, we are just exploring the limits of using low cost materials like cast iron or silicon steel laminations.

Thanks for bringing these ideas up, since they had not been discussed very much yet.

Peter

[hartiberlin]

Stefan,


Welcome to this forum. This is unrelated to the topic of this thread so lets move the discussion to the corresponding thread:

http://www.energeticforum.com/renewable-energy/1438-bedinis-ssg-secrets.html#post13434

This circuit is an abstract form which yields to more charge, not more energy. But in my opinion it has the potential to produce more energy if we use better coils + better core materials + battery instead of a capacitor + correct timing of the pulses.

You are right.
I answered you over here and asked the energy question:

http://www.energeticforum.com/13497-post12.html

Please answer this.

Many thanks.

[elias]

Hi Elias,
does this mean that this circuit:



is producing more energy than was stored as 0.5 x C x V^2 in the beginning in C1 ?
If yes, you would have already creazed a circuit with COP >1 !

Please let us know more about this experiment.
Many thanks.
Regards, Stefan.

Stefan,


Welcome to this forum. This is unrelated to the topic of this thread so lets move the discussion to the corresponding thread:

http://www.energeticforum.com/renewable-energy/1438-bedinis-ssg-secrets.html#post13434

This circuit is an abstract form which yields to more charge, not more energy. But in my opinion it has the potential to produce more energy if we use better coils + better core materials + battery instead of a capacitor + correct timing of the pulses.

[hartiberlin]

Notice how they get shorter in height when there are more spikes per 25 degree window. That means that I can get the pulses even shorter than the rise time, but nevertheless I can not get more than 24% back. Also the higher the frequency of the spikes, the higher pitch noise the motor gives out.
Any suggestions which way to dig next?

Hi Jetijs,
is your stator iron core solid iron or
laminated iron ?
Maybe eddy currents play a major role here,
that you can only get 24% back out ?
Also , did you see, how much you already are in saturation
in your BH curve of the iron core ?

Peter, is it better to drive the iron into saturation
or not ?
Also it probably depends a lot what kind of
core material you are using.
A low hysteresis metgals alloy would probably be much
better than just iron...
Maybe you also have too much hysteresis losses at the moment.

Regards, Stefan.