Actually, the wire has a fixed resistance on the end of it to represent the fixed resistance in the motor.
The formula is (ohms)=(fixedohms)+(motorconstant)*(RPM) Joe Smalley Rural Kitsap County WA Fiesta 48 volts NEDRA 48 volt street conversion record holder [EMAIL PROTECTED] ----- Original Message ----- From: "1sclunn" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, September 29, 2002 7:35 AM Subject: Re: How much power am I losing? > one way to look at this is as the motor being a piece of wire . At a 1 rpm > it might be 10 feet long /minute but at 4000 rpm its 40,000 feet/m long . > If your controller is full on and your pulling 120 amps at 120 volts your > resistance is 1 ohm > ----- Original Message ----- > From: "Seth Murray" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, September 28, 2002 8:56 AM > Subject: Re: How much power am I losing? > > > > Peter VanDerWal wrote: > > > > > the resistance through the brushes on a moving comutator is different > > > than on a stationary one > > > > I have been wondering about this. Lets say I am driving in second > > gear. When I first start my EV moving, the motor wants lots of amps. > > Once it gets up to 4,000 rpms or so, the motor seems to have a limit on > > its current draw, even if I put my foot on the floor (current well > > under the current my batteries and controller can deliver). As soon as > > I shift into 3rd, though, the motor will take all the current my poor > > batteries and controller dish out. The only thing I could thing of was > > that the resistance through the motor must change depending on rpms, > > which because of Ohm's law would allow the motor greater current at > > lower speeds. I know there are other factors involved, but do I have > > any clue of what's going on? =) > > > > Seth > > > > > > -- > > QUESTION INTERNAL COMBUSTION > > > > My electric truck page, with lots of photos and a 25 page conversion > > journal. Check it out! > > http://www.wpi.edu/~sethm (NO MORE POPUPS!!) > > > > My EV Album page > > http://www.austinev.org/evalbum/387.html > > > > >
