I should mention that the low speed growl that I was talking about is really just a curiosity. When I run the motor at less than 200 rpm (200 rpm is still quiet), there is no significant thust from the drive. Running at those speeds, if you stand on the dock and look at the prop, you can clearly see each blade go by and it takes about 20 seconds for the boat to put any pressure on the dock lines. The power load is less an 50W, so there is no pratical reason to try to drive the boat that slow.
I don't think that it is important to resolve this noise because it doesn't effect how I use the boat, it's just a geek thing for me.
Fair winds,
Eric
Marina del Rey, CA
--- In electricboats@yahoogroups.com, "Eric" <ewdysar@...> wrote:
>
> Tom,
>
> I haven't heard anything from the Gen4 controller. As far as I can tell, it is truly silent. My experience with DC controllers in EVs is that some will "whine" at certain settings, I think that it's some sort of harmonic related to PWM or something like that. That noise comes from the controller itself. There may be other mechanical harmonics that show up as motor noise. They may be related to motor mount plates or other physical pieces. These will occur when a minor vibration falls in synch with a piece's natural resonance (like your tires on certain sections of highway) and each pulse is perfectly timed to push the resonance farther, making any noise louder. Usually, a slight change in system speed will break the cycle. The other option is to add a flexible mount or pad to de-couple the vibration source from the "sound board" component.
>
> On my boat, the low-speed growl (very noticable) is the only noise that I didn't expect. I knew that the motor wouldn't be silent, the noise during normal operation is reasonable to me. Once I get the whole installation (wiring, additional components, etc.) locked down, I may try to mitigate some of the mechanical noise that I get today.
>
> Fair winds,
> Eric
>
No comments:
Post a Comment