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4095Re: [solectria_ev] Re: Overhaul Motor recommendations

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  • Jay Grossman
    Jul 1, 2008
    • 0 Attachment
      Wolf,
      As an aside can you tell me about the 3 wheel solar car you worked on. EVA/DC has restored the MIT Aztec solar car a '94 competitor in the Tour de Sol and I wonder if you have any knowledge about this vehicle. Your vehicle description sounds similar.
      Jay H Grossman


      ----- Original Message ----
      From: Wolf <wolf@...>
      To: solectria_ev@yahoogroups.com
      Sent: Monday, June 30, 2008 8:12:47 PM
      Subject: Re: [solectria_ev] Re: Overhaul Motor recommendations



      I just remembered why we where adjusting the sensor... :)

      Our solar car had 3 wheels on it, the two in the front steered, and the
      one in the back was powered by the motor.

      When they made the motor mount for the motor, they placed it infront of
      the wheel, and it was chain drive to the rear wheel, the other side had he
      brake caliper and brake disc.

      When they did this they choose to place the output shaft on the right side
      of the car (right side drive).

      When I wired up the car according to the manual, when the switch was in
      the "forward" position our car went backwards.

      No big deal, we just flipped the wiring on the switch, and all was good...

      However our performance numbers did not match what was expected of the
      motor. So we called up Solectria, and they helped trouble shoot the
      problem. Then they found out that the motor was mounted backwards.

      The motor sensors where actuly slightly advanced to account for the
      controller's feedback lag, so the motor did actuly have a perfered forward
      direction.

      We had to adjust the circuit board with the hall sensors on it, to make
      the motor more efficent in our "forward" direction, it was like 3 or 4 arc
      seconds, but it made a big difference in motor efficency. :)

      Wolf
      *wags his tail*
      www.wolftronix. com

      >
      > There is a procdure that lines up the hall sensors. I remember doing it
      > once on a solectria 5HP BLDC motor on a solar car...
      >
      > This will find all the stator coils (poles):
      >
      > It involved applying a low voltage, like 12 volts to one coil thru a
      > resistor to limit the current to 1 or so amp, the rotor will cog to line
      > up the magnet with the stator. Then you mark the shaft relation to the
      > housing. Then turn the motor by hand till it snaps to the next cog, then
      > using the same mark on the rotor you place another mark on the housing.
      > Keep rotating and marking till you over lap an exsiting one.
      >
      > Then reverse the voltage on the same coil and repeate the procedure.
      >
      > Then hook up the low voltage to the next coil. (use a different color
      > mark)
      >
      > Repeate the same process for all the coils (some coils will yeild the same
      > results, these are the ones that can be connected in series or parallel,
      > if you have 6 wires exposed from the motor).
      >
      > The three sensors should line up with three consecutive marks you made on
      > the housing.
      >
      > Procedure to find the magnets N/S magnets on the rotor.
      >
      > Apply the low voltage to one of the coils, the rotor will cog an line up
      > with a one of the marks you made on the housing. Circle the mark on the
      > housing. Then rotate the motor shaft by hand to the next cog. Transfer the
      > circled mark to the shaft. Repeat this till the marks over lap. The marks
      > on the shaft will be the locations of all of one type of magnets (North or
      > South, by definition, if the motor coils are marked + and - and you have
      > the positive voltage connected ot the + terminal they will be the North
      > magnets).
      >
      > Reverse the voltage and repeate the procedure, this will find the opposite
      > poles.
      >
      > When you are done, you should know where all the N/S magnets are, and you
      > can align the sense magent to the rotor, it should have the same number of
      > poles as the rotor.
      >
      > Note: this is from memory, of something we did about 10 years ago to
      > confirm that our motor was adjusted right... I do remember a division by
      > three might be needed for the magnet locations... It should make sence
      > when all the marks are on the rotor (shaft) and the stator (housing).
      >
      > Hope this helps. :)
      >
      > Wolf
      > *wags his tail*
      > www.wolftronix. com
      >
      >> Charles Bliss:
      >>
      >> To recap:? Your brushless DC motor has a permanent magnet rotor.
      >> Using the analogy of a clock face you have:
      >> S pole (12:00 - 3:00)
      >> N pole (3:00 - 6:00)
      >> S pole (6:00 - 9:00)
      >> N pole (9:00 - 12:00)
      >>
      >> About how many degrees is the interpole gap at 12:00, 3:00, 6:00 and
      >> 9:00?
      >>
      >> Also, when you look at the stator on-end, how many pole teeth are there
      >> in
      >> the stator metal?
      >>
      >> Sincerely,
      >>
      >> Gary Carlson
      >> gjc0@...
      >>
      >>
      >> -----Original Message-----
      >> From: Charles Bliss <cbliss@cbliss. com>
      >> To: solectria_ev@ yahoogroups. com
      >> Sent: Mon, 30 Jun 2008 7:54 am
      >> Subject: RE: [solectria_ev] Re: Overhaul Motor recommendations
      >>
      >>
      >>
      >>
      >>
      >>
      >> I am pretty sure that I need to modify or replace the sensors. At the
      >> minimum, all the wires from the 3 hall effect sensors are brought to the
      >> controller in the original. In the new controller, there are only 6
      >> leads
      >> required, +/- supply and the three phases. The original sensor is a mass
      >> of
      >> machined epoxy. The magnet is four pole 2N, 2S and the sensor looks like
      >> 30
      >> deg separation of the three pickups.
      >>
      >> Any information / help will be appreciated.
      >>
      >> From: solectria_ev@ yahoogroups. com [mailto:solectria_ev@ yahoogroups. com]
      >> On
      >> Behalf Of ldr214
      >> Sent: Monday, June 30, 2008 7:41 AM
      >> To: solectria_ev@ yahoogroups. com
      >> Subject: [solectria_ev] Re: Overhaul Motor recommendations
      >>
      >> Solectria had a lot of different suppliers and changed many things as
      >> the cars evolved. It would be wise for all of us to post specifics
      >> when we have a problem or comment. Even amoung the rather similiar 96
      >> and up Force productiuon there are still variations, such as nicad,
      >> chargers, avcon inlets and so on.
      >>
      >> Wolf which motor are you referring to in your post? I don't know if
      >> the truck used the same one as in the 97 Force (ACgtx20).
      >>
      >> Kruspan has some support for disks and sensors.
      >>
      >> Mike
      >> 97
      >>
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      >>
      >>
      >>
      >>
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      >>
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      >>
      >>
      >
      >






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