hehe, guess I don't know too much about motors now do I?? =) here's a
dumb question - if our motor here is making all this back EMF, if we
are coasting down a hill and keep on winding the motor up and up and up
until the BEMF exceeds the input voltage, would we not have regen? My
understanding was that series motors are tricky to do regen with. Why
would that be, if we have this apparently straightforward EMF thing
going on? Thanks for the info.
"Us racers swear at them..." someday, Rich, I will give you a run for
your money (or a new PFC) =)
Seth
On Saturday, September 28, 2002, at 01:12 PM, Rich Rudman wrote:
> Seth Murray wrote:
>>
>> 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
>
> HOooooH ha ha HHHHEEEE! Yea rather obvious is the BACK EMF of the
> motor.
> As it spins up it becomes a generator, you need to over come this with
> more volts or your motor will spin up to a certain speed and then wind
> out no futrther!!!!
> Basic V/F ratio. volts to Frequency or RPM same thing.
> All motors have rpm and torque curves. You are just seeing them .
> Us racers swear at them and try to manipulate them to our best uses.
>
> Check the motor curves from Advanced DC and from Rod at EVparts, and
> Ken
> Koch at KTA.
>
>
> --
> Rich Rudman
> Manzanita Micro
> www.manzanitamicro.com
> 1-360-297-7383,Cell 1-360-620-6266
>
>
>
>
--
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
