Rotating Magnetic Field's and Inductors.

[EMJunkie]

Nice Video too!!!

Induction, Time Rate of Change of the Magnetic Field in the proximity of a Conductor. Little bit of both emf = Bvl and also emf = dPhi/dt all there I would say.


   Chris Sykes
       hyiq.org

[tinman]

It looks like one of the scope shots that is with the rotor is showing the rotor producing some generating in the waveform.  Im not sure i understand all of the stepping in the waveform without the rotor.

Mags

You mean as the scope shot below show's.
I would say that my FG is unable to supply enough current to the base of the transistor to switch it on hard enough when the current reaches a certain level flowing through the collector/emitter junction-->maybe we could call this transistor slip lol.. If the transistor is switched on hard enough,then the voltage across the collector/emitter should be zero during on time--either that,or the transistor is not so good anymore  . I would be better off using a mosfet,which i will be changing to from now on.

But that is just a guess.


Brad

[verpies]

An Inductor will take 5 Time Constants to charge to 99.3% of its Current Carrying Capacity. Why they chose 99.3% I don't know. This is sometimes conflicting, 99.3 and 99.7 are common numbers for the same thing.

It is 99.32620530% because 1 - (1/e⁵) is that much

Also, it should not be called a "Current Carrying Capacity" but a V/R limit - a consequence of the Ohm's Law.
The V/R limit is a completely different concept than the core saturation limit.
It is all described in detail here.

[tinman]

With a few minor adjustments,we have managed to increase the efficiency even further.
I have the duty cycle set spot on now,and not only did that decrease the P/in (as it would),it also increased the P/out.

So now it is time to put it together as a pulse motor,where we will now use the trigger coil to fire the transistor. Lets see if we can break the 50% efficiency barrier as far as electrical P/in and P/out go's.


Brad

https://www.youtube.com/watch?v=4leXKDz7D8c

[tinman]

Below are the two scope shots that are from the last video(post above),along with the P/in P/out calculations.


P/in with rotor is
180mA @ 12.47v = 2.246 watts
P/out is 74mA @ 12.48v
Efficiency is 41.22%

P/in without rotor
240mA @ 12.47v
P/out is 12.49v @ 74mA = 2.992 watts
Efficiency is 30.88%

Once again-with the duty cycle set at optimum coil performance,the rotor and spinning magnets increased the efficiency by 10.34%.


Brad