Controller circuit for Hilden Brandt motor needed..

[Honk]

Yes, they occur more often at higher rpm but each back emf pulse stays at the power level and voltage regardless of the rpm at load.
Is does not matter that they occur more often. The controller will handle the emf spike and return it to the coil of the next phase. This will save energy.
At 500 RPM the motor generates 50 back emf spikes/second. At 3000 RPM the motor generates 300 back emf spikes/second.
But 300Hz of back emf spikes is no match for modern electronics that can easily cope with many hundreds of thousands hertz.

[Gregory]

Nice motor Jack!

As I see you use three rotors, 1 valve per rotor, and a 120 degrees offset for the timing of the valves, I guess.

Great setup, I like it. Best of luck to you & Honk!

There is an option mentioned before, to gear down the rotational output of the motor, and attach it to a low Rpm windmill generator. But now as I read you are planning to build a generator to exactly fit with the requirements of the new motor.

So, at what Rpm level you are planning to run the self-running test?

[Liberty]

Yes, they occur more often at higher rpm but each back emf pulse stays at the power level and voltage regardless of the rpm at load.
Is does not matter that they occur more often. The controller will handle the emf spike and return it to the coil of the next phase. This will save energy.
At 500 RPM the motor generates 50 back emf spikes/second. At 3000 RPM the motor generates 300 back emf spikes/second.
But 300Hz of back emf spikes is no match for modern electronics that can easily cope with many hundreds of thousands hertz.

Hi Honk,

Do you find that the bemf pulses are of a higher impedance nature and return in a form of much higher voltage and lower current than the voltage that the motor normally operates on?  I notice this on 6 or 12v relay coils etc...   (It may depend on the number of turns in the coil).  To avoid an impedance mismatch and power loss from the bemf pulse, does the circuit step down the pulse to a lower, more managable voltage and useable current before returning it to the motor for usable power, and can the electronics handle the high voltage spike that occurs on bemf pulses?

[Humbugger]

Yes, they occur more often at higher rpm but each back emf pulse stays at the power level and voltage regardless of the rpm at load.
Is does not matter that they occur more often. The controller will handle the emf spike and return it to the coil of the next phase. This will save energy.
At 500 RPM the motor generates 50 back emf spikes/second. At 3000 RPM the motor generates 300 back emf spikes/second.
But 300Hz of back emf spikes is no match for modern electronics that can easily cope with many hundreds of thousands hertz.

@Honk...okay...sounds like you've got it under control then...thanks for clarifying.  By the way, as a fellow product developer (power electronics) I have to say I'm impressed with your speed and professional-looking job on the controller.  It looks kind of small to me, and I was taken aback by the 20W worth of big sandbox resistors there (for a 45w unit running 92% eff, that must be pretty extreme overkill on something!), but I'm not privy to the specs and requirements, so, I guess I will just have to wonder!

My last high power project was using RF HV Mosfets in a extremely compact 96VDC-to-40.68MHz RF generator of 1200W RFoutput.  It took a year for me to develop.  These RF generators are, since 2001, used in every Synrad F-series Firestar CO2 laser from 100W to 400W optical output.  I mention this so that you will understand I am aware of what modern electronics can handle.  The biggest problem I had was a back-emf problem that is a bit different than in motors and electromagnets. 

In RF-driven laser tubes, there is typically a very high Q resonant circuit driven by RF which is used both for ignition and running modes.  To strike the plasma up in these particular tubes, reactive power well in excess of 20KVAR is required to be shoved into this ultra-hi-Q internal network consisting of the laser tube's inherent inter-electrode capacitances and a set of a dozen or so gold-plated beryllium-copper inductors placed in parallel over the length of the electrodes. 

Fortunately, the ignition only requires a few microsecond long pulse at 40.68 MHz so it can be done with the same RF amp, but, when the laser tube won't light up for some reason (bad gas mix, off-tuned resonator, whatever) all hell would break loose at the end of the ignition pulse when the energy stored in that ultra high Q circuit would come flying back into the RF output stage, whose MOSFETs were now all off.  This brought some pretty big energy with rising voltages that occasionally went past the 500V rating and the avalanche rating of the MOSFETs...bang!  Took some doing to resolve. 

Normally, once the plasma in the tube began to form, it would easily absorb all the energy and things ran just fine...no back-spike at all.  All that reactive power would change to true power, asthe plasma load is like a nice big resistor and the RF tuning was set up for low VSWR during run-mode as opposed to start mode.

It sounds like, when I hear that the back emf from the motor is 2/3 of the input power on an ongoing basis no matter the RPM or mechanical load...well...the only way I could think to explain that is poor coupling between electromagnets and motor armature but that makes no sense if the motor is really as efficient as purported!  I often wonder how much of my (and others) confusion comes from not communicating on the same wavelength with the same terminology and how much comes from not measuring things correctly. 

Seems like in a motor where the coefficient of coupling was extremely high, the input current and BEMF would be highly dependent on mechanical loading!  Anyway...you guys are doing some really neat looking work and with what appears to be top-notch skill levels...world-class actually.  I sure hope the concept pans out for you, fellas!  I'm an OU skeptic, as you may have gathered.

[Honk]

Hi Honk,

Do you find that the bemf pulses are of a higher impedance nature and return in a form of much higher voltage and lower current than the voltage that the motor normally operates on?  I notice this on 6 or 12v relay coils etc...   (It may depend on the number of turns in the coil).  To avoid an impedance mismatch and power loss from the bemf pulse, does the circuit step down the pulse to a lower, more managable voltage and useable current before returning it to the motor for usable power, and can the electronics handle the high voltage spike that occurs on bemf pulses?

Hi

You are close in some of your assumption's but still far away from how the controller handle the back emf.
Be patient....hehehe....sometime in the close future I will reveal the secret of the Flux Booster Controller.