Tom,
My glib answer was going to be to set the "noise" parameter to 0. Maybe putting in a negative value would make the controller absorb some of the noise from other sources. :)
As a customer of James, I'm aware of the effort and complexity of these issues and what he's gone through to optimize his system. I would say that the simpler controllers have fewer parameters to mess with, but some attributes like the hum (whine) of a PWM controller can't be adjusted away. The Gen4 is way more flexible but requires more technical expertise and equipment to optimize it.
It's kind of like the changes to the cars that we drive. There wasn't anything I couldn't do to tune an engine with carbs. I even tweaked an older analog fuel injection system by hand. But the last few cars that I've bought go directly to specialists for whatever work they need. I get my "tweaking" fix with various projects like my Porsche 914 V8 conversion that I've been messing with and upgrading for 20 years and a stock 1915 Ford Model T that has been in the family since the early 1960's.
I think that buying a tuned electric drive system for my boat has put me way ahead of where I would be if I did it all myself. After converting a couple of cars to electric over decade ago, I've got the basic expertise, but that experience is what turned me towards a complete system with support. I'd rather be sailing than spending time messing about with the drive.
Don't get me wrong,I know that most DIY systems are perfectly functional and work fine just bolted together. However, I think that the complete systems offered by the various vendors here are more predictable and might be considered better, depending on the judging criteria, i.e. noise or efficiency.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
>
> Thanks for the scoop, James.
> If I didn't already have a $450 MillipaK, It'd be easier to pay out $595 for the new Gen4. But that will have to wait.
>
> PS: At idle, the MillipaK draws a lot less than 750A. :)
> -Tom
>
> --- In electricboats@yahoogroups.com, James Lambden <james@> wrote:
> >
> >
> >
> > There are about 100 variables to characterizing a controller for a
> > certain motor.
> >
> > I was present when the Sevcon Engineers characterized the Gen 4 for
> > the Mars 20 turn, 28 turn, and double stator 28 turn motors.
> >
> > They run the motor on an oscilloscope, spin the motor as a generator
> > to find out its voltage to rpm constant, and input other variables
> > from the electrical design of the motor.
> >
> > There are error control loops for past, present and future operation,
> > each weighted differently. Change one variable too far the wrong
> > way and the motor will not perform, or act like a speaker, or hickup,
> > or vibrate.
> >
> > I characterized the Gen 4 for the double stator motor myself, and had
> > it running fairly well, but notice dramatic improvements when
> > Sevcon's engineers did the characterization process. Its a very
> > difficult task and requires specialized training, not to mention the
> > software to make the changes. And then the program is tested on a
> > motor hooked up to a dyno....
> >
> >
> > James
> >
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