Wayne Weedon wrote: >Jon Elson wrote: > > >>I have been working on a drive for brushless servo motors. I just got the >>prototype running, and I am impressed by how well it is working, >>already. I'm working with a Pittman 4443 motor I got on eBay a while >>ago. These would make great motors for small routers and desktop >>mills. They are NEMA size 17 but long. Amazingly, the VHDL code for >>the drive's CPLD worked first time! I sure didn't expect that! So, I am >>already at the step to design a board for it. >> >> >> >> >Jon > >Sounds interesting. Sinusoidal commutation? Perhaps throw a page >together to show your progress ;) > > > Very simple 6-step commutation, driven entirely by the hall sensors on the motor. That way, it doesn't need to know anything about the motor, or see the encoder signals. It does require a motor with the extra hall signals, but can handle any motor that has them. Sinusoidal commutation requires the driver to know the encoder resolution per motor pole, and have some kind of absolute feature on the encoder. This amp has no current feedback, other than through the position as sensed by the encoder. But, even with no load on the shaft, it performed amazingly well, although there was some slight velocity ripple at each commutation. When attached to a machine, it will not be a problem unless you try it with a 100 CPR encoder or something like that.
>I very reluctantly put steppers on my Leadwell VMC wghen I could not >find drivers I would be SURE would work with the original motors. >(300w, Halls + encoders 5000ppr). Still it's now almost earned some >new motors. > > Well, I should have these done in a month or two, if you still have the motors. 5000 cycle/rev encoders should give great resolution and smooth motion. If you have any question about compatibility, I'm going to be making the following deal to all customers : send me one of your motors, and I will figure out the correct wiring and all parameters for you, before you buy. (Of course, once I've seen a particular model of motor, I won't need to do this again and will list the connection info on my web pages. I will even list the ones I know are not compatible, like Yaskawa Servo-Pak motors, which have proprietary encoder C channels and no hall sensors.) Jon ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
