Alright....a little back story, because I truly suck at real "data". I scribble notes and have thousands of pages (not just this project) but it is totally unreadable to anyone. I do things by feel and what peeks my interest, unless its something useful then I do my best to get every point documented so that it can be useful for someone else.
When i first got everything up and running I did a lot of testing of this and that and didn't really find anything special. But for the sake of documenting the process I will post a description of what I did.
At first I was using some crude brush system with a flat piece of brass mounted to the shaft, a positive brush made of thick pencil lead. for the other brush I used multiple different things in an attempt that had some success but was just "not right" so I left the device alone for a while. The success was being able to have it running with my power supply reading zero on the current meter, but that boiled down to the duty cycle being so low that its just simply didn't "see" when the current was coming out.
Then I switched to an arduino, the sketch I wrote up, and actually used, was about the fifteenth iteration. after much frustration trying to do to much at one time I settled on using two hall sensors with interrupts on the arduino. One to turn on a pin and one to turn off the pic. With this I was able to turn the drive coil on or off at any angle and for any duration that I wanted. I originally wanted to use the output to switch a mechanical relay to get rid of the "fried semiconductor" syndrome and have something that isolated the "switching" from the "switched". I soon realized that mechanical relays take anywhere from 5 to 15 milliseconds, which on a four pole rotor in the best scenario would be a max of about 50 rpm. So that idea was dead, but having put the time into the sketch I just used a mosfet circuit added to the arduino to power the drive.
So ...once I had it running I tried every turn on angle, duration of pulse, everything I could think of with the aid of an led and reflective strp, to basically get a "feel" for how it ran. Once I was comfortable with it I tested it in a simple, and probably not the best, way. I took the "input" and ran it through a known resistor value so I could use my scope and calculate the current going into the system. I then took many different resistors and many different capacitors on the output of the coils. I only ever did one coil at a time, so it was either a single diode to a cap or a bridge rectifier to a cap. I put the "many different resistors" across the cap to see what the sustained voltage was while the system was running. This leaves out many aspects of testing to get the "true" in vs out. however I was able to get the idea of what changes caused what effects. The best I ever got from this testing was about %50 of what I put in across the resistor on the out.
During that testing I spent many days thinking about this thing and what all was stated in the patent. I started thinking about how JB talked about reversing the back emf. While most of my VERY basic and incorrect way of testing showed that the lowest current draw was at higher speed and the higher speed came from a longer on-time. If ran at a low duration from TDC I never got any effect that showed a noticeable difference in the back-emf. I will still be doing further testing in the future on this, But me being me I moved on to test what I was thinking.
Given the above information I started to think that if the back emf is reversed, well away from the cores after a longer pulse, then it wont have much effect. But if the back emf or the inductive collapse happened when they were very close to the cores what would happen? So I swapped the wires and halls and decided to test it in the "pull" configuration. partly just to see what difference it made and partly the idea of what would the effects be on an inductive collapse that happens while the magnetic strength is still increasing (when the coil turns off before or after TDC and the collapse has to "ride" on that changing flux). Before I could get any real testing done I noticed something else That intrigued me.
There was not just one inductive collapse there were many! after the coil turned off it did its normal thing then it would pulse back on repeatedly at about 275 Khz while climbing in voltage until it would just stop and level out. I will post some scope shots of this soon and am going to be testing this further tonight to try and figure out what is going on. I have already ruled out a feedback from the coil to the hall and am scratching my head as to what is making this happen. Maybe this is what is supposed to happen! I dont know.
I am sorry for the super long post and no real information that can help anyone. But I figured having the "back story" would help and I will be posting soon with any and every detail I can on what is going on and if it has benifits or not to what we are all working towards.
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Originally Posted by Bradley Malone
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