# Motor theory

From what I’m seeing is all the AC motors are using a sine wave, or multiple sine waves to power them. But why? When the shaft magnet passes the coil, the field is at its strongest and creates the most torque. However after it passes over the coil it drags it in the opposed direction. Which is just counterproductive. I propose using a tangent wave, so that as soon as the magnet passes over the coil the coil changes polarity to repel the magnet.

This seems like the most efficient method of propulsions. But I have not seen anyone do this. And this seems like common sense to me. Since no one is doing this I assume (yes, I know) that someone has already thought of this and there are flaws or drawbacks in this design.

Any thoughts

Can you give me a drawing of a sample tangent wave…I honestly can’t picture one

I don’t know exactly what you are asking.

``````If you’re asking what a tangent wave is (it's the resulting graph of y=tan(x))
``````
``````If you’re asking how it's going to be used, then It will take me a little longer. You just over lap 4 tangent waves one on top of each other, so that they are evenly spaced.
``````

The goal of this design is that once the motor magnet passes the coil. The coils will reverse polarity to create maximum torque.

AC is sinusoidal… it DOES repel once it passes the coil. Each phase is positive for 1/2 period, and then negative for 1/2 period. It reaches peak at the coil.

Its not about polarity, its about forces.

http://www.shermanlab.com/xmwang/javappl/acMotor1.html

each phase maxes out as the magnet is passing the coil, then it decreases and the next coil takes over. You cannot just instantaniously reverse the field on that or its going to pull towards the center of the shaft, and not tangential. You have to consider the moments and forces with a motor. a motor gets its most torque when the field and magnet are aligned.

Essentially, its kind of like a bike pedal. If you push on the pedal just off-center of top dead center, it goes slowly forward and the force is maxxed out when the pedal is 90 degrees from top dead center. Same thing for a motor.

well not my EV per say, its my dads

but I’m working on it too. You can see me in the picture (I’m dirty from crawling under the car)

http://www.evalbum.com/2064

Well I want the motor to create a moment, I think that is the howl point of a motor. And the motor sould pull from the top and bottom evenly sence its a 4 phase motor. So it sould not put any extra strain of the shaft.

And the reson I thought of using a tangent wave insted of a sine wave; Is that the coils in a sine wave driven motor create a net feild, and the rotor lags behind the maximum flux. This seams inefficant to me, so I thought I could design a motor that would run the motor in the max flux.

Here is a link I think that you can see what happens in the sine wave motor
http://www.eu.necel.com/applications/industrial/01_motor_control/images/3phasesync.gif

(OK, I don’t know if I worded this well, or if I used correct terminology. I hope that you can understand what I’m saying)

I’ve never seen a 4 phase motor, so I’m not so sure what you’re talking about.

I know you want to create a moment, but if you’re saying you want to switch the polarity once it passes the center of the coil, the FORCE will only be a few centimeters on the x axis from the center of the shaft, creating almost NO force. See my pedal example above.

Second, you are going to have a TOUGH time creating a tangential wave with electronics… they don’t like switching polarities from high potentials (going from Vmax to -Vmax almost instantaniously). Inductors don’t like switching polarities either.

The whole thing I think you’re missing is the actual understanding of the forces/magnetics and moments involved. Its got alot of vector math and phasors.

The sinusoidal motor MAXIMIZES the force in its design.

here’s a page with an animation of 2 phases showing the magnetic force vectors and the resulting force vector.
http://www.physclips.unsw.edu.au/jw/electricmotors.html#ACmotor

I want to use a 4 phase motor to canlsel out the electro magnetic radiation. I got the idea when resurching polyphase motors.

I’ll have to show you how a came up with a tangent phase motor later.

maybe your right, I’m not going to give up untill I know I’m wrong. (which I think I might be)

Thanks for your help.

PS (sorry I can’t use spell check on this computer)

well, you’ll have a hard time designing a 4-phase motor, and it’l be almost impossible to find one that’s already built. there isn’t 4-phase AC in the industrial world, just 3 phases.

I think I am going to go back to a 3 phase motor. You are right, to hard to prototype, and (as I now know) it wast energy.