# Increasing Mileage, Not Overnuity, simple Tesla Circuits...



## clone477 (Sep 21, 2008)

I forgot to add the link to the patent for those interested.

http://rpmgt.org/588177.html


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## Technologic (Jul 20, 2008)

clone477 said:


> The controllers for an EV are to expensive to experiment with to blow up. This will have a great impact on EV mileage as far as Im concern, and I really think we should look at this closely. Fernando


I'm fairly certain the field never collapses during PWM control... it effectively functions like DC current unless I'm mistaken. Also I'm unsure where this energy is coming from exacting that you are storing in caps.


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## clone477 (Sep 21, 2008)

My description was most likely not the best, but if you read Tesla's words, then you will get a better idea. Also Tesla's controller in that patent was designed to provide a sharp cutoff and turn on, square wave so to speak. It seems to be the same as PWM with solid state circuitry today. But that's why I am here, correct me if Im wrong.


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## Anaerin (Feb 4, 2009)

Okay, so what you're suggesting (If I've got this straight) is that we use a capacitor across the motor to collect the back EMF of the collapsing magnetic field during the "off" part of the PWM duty cycle, and use that to add to/increase the available power in the system.

I believe (Though I could be wrong) that this would cause the motor to go from powering to dragging and back in rapid succession, as voltage is first put in, then taken out of, the drive coils, causing an overall slowing in the motor as you're using it's rotating mass (Along with the rest of the drivetrain) as a big flywheel. So while you may get some power out (not much, I'd be willing to bet) you will also be "braking" the motor, causing it to run slower.


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## clone477 (Sep 21, 2008)

I think you are misunderstanding the circuit, and Im not saying that to be condensending. I have been reading and understanding this circuit for over a year. I can finally say I totally understand it. You have to read though and examin the patent completely. 

In a nut shell....
On the off portion of the PWM signal from the controller of an EV, there is a huge voltage spike as the field collapses, this is how an ignition coil works in a gas engine. 

This voltage spike, that is usually wasted(I belive the Mosfets have a diode to deal with this??) is instead used to to charge a cap to higher than traction battery voltage.

Then the next time the mosfets from the controller turn "ON", it completes a parellel LC circuit, by shorting the cap(remember the cap was fully charged).

This parrellel LC resonant circuit contains a primary of a transformer as the "L". 

The Parellel LC will produce a damped wave, which is kept ringing in resonance with the continual collapse of the motor coils. 

Then the primary is resonantly tuned to the secondary. Large amounts of power and developed using this.


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## kek_63 (Apr 20, 2008)

I have to agree with Technoligic on this one - the field doesn't collapse. I wish you luck in your quest for increased mileage, but I don't think this idea of Tesla's is the answer.

And as far as your request for "no flaming", I think that you will find that the word *overunity* is treated as a glowing bbq briquet on this forum. Fortunately there aren't too many members who keep a bottle of lighter fluid on their desk.

Keith


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## clone477 (Sep 21, 2008)

kek_63 said:


> I have to agree with Technoligic on this one - the field doesn't collapse. I wish you luck in your quest for increased mileage, but I don't think this idea of Tesla's is the answer.
> 
> And as far as your request for "no flaming", I think that you will find that the word *overunity* is treated as a glowing bbq briquet on this forum. Fortunately there aren't too many members who keep a bottle of lighter fluid on their desk.
> 
> Keith


 I respect your opinion, but, why do we use flyback diodes in mosfet and in an EV setup in general?? Is it not to deal with the high voltage spike? Here is a quick link.....

http://en.wikipedia.org/wiki/Flyback_diode


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## Anaerin (Feb 4, 2009)

clone477 said:


> I respect your opinion, but, why do we use flyback diodes in mosfet and in an EV setup in general?? Is it not to deal with the high voltage spike?


It's because a spinning, permanent magnet motor will act as a generator as well, and when the MOSFET isn't conducting, it is slammed with the current from this spinning motor, which can seriously damage the MOSFET. If you attempted to take the current from the motor, feeding it into a capacitor for example, the load would cause the motor to drag, as regen causes it to, slowing the motor and producing drag.

So yes, you can get power out during the "Off" portion of a PWM cycle, but you will be putting a drag on the motor, slowing it and the vehicle down, and you probably won't get enough power out to make up for the drag.


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## bblocher (Jul 30, 2008)

clone477 said:


> This voltage spike, that is usually wasted(I belive the Mosfets have a diode to deal with this??) is instead used to to charge a cap to higher than traction battery voltage.


I'm really not sure if there is a field collapse. It takes a certain amount of time to build and tear down a magnetic field through induction. I believe the time it takes for this to happen is based off the number of windings in the coil but could be wrong there. Regardless of all that, getting more voltage out of the coil than you put in is also not going to happen unless the winding counts changed twice during each cycle.

However, history has shown many times that the masses can be wrong when one is right. What did you do in your small scale test to prove this theory? That well documented and measured would be interesting to see.


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## Qmavam (Aug 17, 2008)

clone477 said:


> Here is the quick on it....
> 
> Basically you are driving a DC motor with a PWM circuit, 50/50 duty cycle. Tesla used a controller to cause the make and break of the motor. Everytime the circuit is broken, there is a huge collapse of the field coils in the motor. This huge voltage collapse is collected in a capacitor. When the controller reconnects the motor circuit, this shorts out the cap causing a resonanlt tuned circuit, between the cap and the small inductor(primary of a xformer). That small inductor is the primary of a transformer, attached to a secondary. This secondary has its own capacitance(the ozone plates). This secondary output can be rectified to DC very easily to charge the battery bank.
> 
> ...


 
You say, "The RPM of the motor controls the frequency of the collapse."
Then you say, "The frequency of the collapse is a harmonic of the small inductance and capacitor." Which is is?
Frequency is dependent on the inductance, the capacitance and the resistance.
Next, the collapsing field is not wasted it is recirculated through the freewheeling diode and the motor.
Here is a thread from sci.electronics.design that you might get some info
about the field collapse. 
http://groups.google.com/group/sci....group:sci.electronics.design#f024274cff3cd5f1
Mike


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## clone477 (Sep 21, 2008)

Guys, 
All I suggested in the first post is that people study the patent, it will answer all these questions I'm getting. I did not design this circuit, I'm just suggesting it for our application. We are all after the same goal, increased mileage with an EV. 

I'll leave at this.
Thanks Fern


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## 144VDC (Jan 25, 2009)

clone477,
I am sure Qmavam is right that the freewheel diode is allowing the motor to use the energy stored in the winding inductance when current from the battery is switched off.

I believe Tesla was doing the same with the equipment he had in the days before electronic control.

I think it is good that people bring up these ideas so they can be discussed; you never know when you might find a good one.

I have one main rule when trying to improve efficiency, look for the heat, if it gets hot it's wasting energy. 
Jerry


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