Brushless DC motors - gotta study and learn

[Leitmotif]

Does anyone know of a good start with basic and get to advanced reading material on brushless DC motors. Why I ask I need to learn more. Have a in wheel hub motor off a scooter that we wanted to test and see if would rotate. Phase to phase reads approx 0.3 ohm phase to ground 1M or better. rotates freely. -- So motor looks OK so far. Tried running for one or two second on 1. AB non vector VFD no luck although it was harder to turn tire when energized 2. Old six step inverter motor would turn approx 1/8 turn 3. Applied DC to two of 3 phase leads motor would turn approx 1/8 turn did on all three pairs and turned each time SO we conclude the motor is OK it will turn when energized move on to the controller and replace both capacitors - one is blown out. try controller and see if can make run IF that fails students decide to either scrap project buy new controller From another source we see the pulse shape may be special for this not a PWM and not a full six step. So we do not know what wave form a controller must have to make motor run. Scooter is 1. owned by a group of EV enthusiasts 2. Donated by an electric vehicle shop who gave up on it and is a basket case 3 We are doing this project as Inependent Study in association with high school students and is THEIR project all I do is mentor and advise they make own decisions 4. complete mystery no markings not even a serial number anywhere on scooter. Students were able to track down US representative who is helpful but gave wrong manual - working on that issue 5. This is a great lesson to students on reality of working in industry with equipment ie "do we have a manual" etc etc. 6. These are good hard working high achieving kids who are worthy of your help. Any help study info on what the waveform may be would be great. Dan Bentler

[Peter Nachtwey]

I go to the University of Texas Instruments. You can find what you need by searching "TI Brushless DC Motor control" You can find the chips used to control BLDC motors and the app notes are very good. Start there. We actually bought a start BLDC motor kit using a TI DSP. It cost $400 but it included two BLDC motors, the DSP and driver board and software. Note other DSP sites have information too. You should also check Analog Devices and Freescale. The DSP manufacturers are trying to make it easy to use their chips.

[Leitmotif]

Peter Good stuff and thank you. Looked at them and gotta look again to learn even more. As example up to a day or so ago I thought that BLDC and PMSM were synonomous terms for motors they are not from all I have read - although closely related BLDC takes a "near DC" almost like a six step applied in sequence to each phase compared to PMSM uses a more sinusoidal PWM. Was looking for a book but the Freescale and TI web sites were most helpful. Dan Bentler

[Peter Nachtwey]

Here is more info. There is a lot. http://www.pdfgeni.com/book/BLDC-DSP-pdf.html Research the way I do it. There are many such PDF search engines. I have GBs of pdf files that I have download on all sorts of topics.

[Leitmotif]

Thanks Peter Evaluating and learning. Sure hope you do not want book report on all. Dan