Of course its correct that the 5k reading should be in the centre position (zero speed).I have read that somone programmed his controller to be zero speed above about 3.5 k setting . This allows for any small error in setting the lever to stop. I'll put a wiring diagram in the files section to show how to use a 10K pot or 20 K pot. A good quality pot should be obtainable from electronic suppliers such as Digikey for less than $10.0.
Chris S
--- In electricboats@
>
> Interesting way of doing it Hans . But a pot bridged as you suggest will give a non linear response and the 5k would be in the centre position , not at the ends
> . personallY i might use a pair of easilly obtained 10K pots . And have a mechanical arrangement and switching so that half travel of either pot is used in the two directions.
>
> regards
> Chris S
>
> --- In electricboats@
> >
> > Russ,
> >
> > I did something like what you are trying to do. I have a sevcon millipak, but mine is for the brushed motor. I have a joystick/ control unit that I built up myself with parts I scored on ebay and radioshack. The joystick itself is from a scissor lift truck. Do you have the sevcon hand held calibrator unit? It is sort of expensive, but you can tailor any aspect of the performance of the unit to your specs, and you can easily adapt a 3 dollar potentiometer to do what you are trying to do. If you do not have the calibrator you can still do it, but it is not that intuitive.
> >
> > Most three terminal potentiometers will register 1/4 of their rated resistance across the middle and the outside terminals when the dial is in the middle of the travel of its turning radius, AND the outside terminals are bridged together. The best way to see this is just buy a couple of pots at radioshack to experiment with. Try a 20k pot if you can get it. It is probably easier to find a 25k pot if I remember correctly. Hook up your ohmmeter from the middle to one of the outside terminals, and then bridge the outside terminals. It's been a while since I have done this so take what I say with a grain of salt, but you should find a 20k pot will behave the way you desire. The trick then becomes having a forward/ reverse switching system that recognizes your joystick position.
> >
> > You could always spend the dough and buy an electric yacht controller. I think it is adaptable to the millipak. The sevcon millipak also recognizes a digital input protocol. I sae a proper used marine ZF electronic throttle joystick at Minnies yacht surplus in Newport CA for about 50 bucks. You could probably adapt one of those units.
> >
> > Â With the calibator from sevcon you can program the millipak to recognize 0 and 100% power demand from your different throttle positions. It took me a while to get the hang of all this, but once I did, I appreciated all the abilities to customize the performance of my controller
> >
> > One word of caution. I would use a good sealed potentiometer. You can get them from a better electronic supply store for about 10-15 dollars. I still have a cheap one in my control and sometimes it gives me slightly erratic behaviour. It is OK to get your foot in the door and breadboard your system, but eventually you should get a good one.
> >
> > Hope this makes some sense.
> >
> > Hans K.
> >
> > --- On Tue, 12/22/09, russ1302 <no_reply@yahoogroup
> >
> > From: russ1302 <no_reply@yahoogroup
> > Subject: [Electric Boats] Forward/ reverse potentiometer.
> > To: electricboats@
> > Date: Tuesday, December 22, 2009, 12:09 PM
> >
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> > Â
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> > I'm looking for a Potentiometer 0-5k, that turns both directions. I want to make a throttle that is neutral in the center with forward throttle one direction and reverse throttle the other. Does anyone have anything like that? I want to make it simple like the Electric Yachts throttle. I'm using a sevcon Millipak with Mars 48 volt brushless.
> >
> >
> >
> > Thanks
> >
> > Russ
> >
>
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