T-Pain Is On A Boat: Re: [Electric Boats] Forward/ reverse potentiometer.

Thursday, December 31, 2009

Re: [Electric Boats] Forward/ reverse potentiometer.

Mr. Searchin,

The throttle ramp and neutral delay parameters are set to prevent "instantaneous" switching from forward to reverse - it takes maybe a second or two to go from F to R. The motor has plenty of power to overcome the windmill action of the prop through the water. The delay is plenty of time to minimize the inertial load of the spinning components.

Denny

----- Original Message -----

From: im_searchin

To: electricboats@yahoogroups.com

Sent: Thursday, December 31, 2009 1:19 AM

Subject: Re: [Electric Boats] Forward/ reverse potentiometer.

Dennis;
Does the new firmware apply a low current to stop the shaft from turning before allowing your selected input to be applied? You have the mass of the prop to stop plus the speed of the water trying to spin the prop to overcome.
thanks;

--- In electricboats@yahoogroups.com, "dennis wolfe" <dwolfe@...> wrote:
>
> Matt's answer is probably the correct explanation for your hesitation but there is another possibility.
>
> Your controller knows the speed and direction of the motor shaft via the hall sensors. It may not give you reverse current until it detects the shaft has stopped moving forward.
>
> I had a real problem with my Sevcon PMAC at first. It took 15 seconds for the boat to stop coasting forward; that is a long time to wait for reverse. Sevcon changed the controller's firmware to fix the problem.
>
> Denny Wolfe
> www.wolfEboats.com
>