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8459Re: [solectria_ev] Controller delta vs WYE [was Re: Upgrade voltage - DC-DC Converter ...]

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  • Lawrence Winiarski
    Oct 27, 2012
    • 0 Attachment
      Just lurking and not a motor expert, but wouldn't the lag of the phasor (and of course the total current) depend more heavily on the slip?
      I'd think the actual reactive inductance varies all over the place as the car goes up and down hills and shifts from power => regen.

      Not saying the static inductance doesn't matter, but curious how much the phasor angle varies from the static position.
       
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      ________________________________
      From: geo_homsy2 <geo.homsy@...>
      To: solectria_ev@yahoogroups.com
      Sent: Saturday, October 27, 2012 11:14 AM
      Subject: [solectria_ev] Controller delta vs WYE [was Re: Upgrade voltage - DC-DC Converter ...]


       
      Ahaa! Thanks, Wolf!

      --- In solectria_ev@yahoogroups.com, Wolf <wolf@...> wrote:
      >
      > The controller cares because the motor has twice the inductance when wired
      > in WYE, thus the phasor needs to be advanced to counteract the lagged
      > current.
      > On Oct 26, 2012 1:26 AM, "geo_homsy2" <geo.homsy@...> wrote:
      >
      > > **
      > >
      > >
      > > Hi Josh-
      > >
      > > I'm familiar with phasor analysis, and I understand the difference between
      > > a motor wired delta, and a motor wired wye. I like to think of it as
      > > changing the voltage- and current- constants of the motor, by a factor of
      > > sqrt(3) = 1.73, as you said.
      > >
      > > What I do NOT understand, however, is why the controller cares! Phases R,
      > > S, and T, should be basically the same, but 120 degrees out of phase.
      > > Period, end of story. I don't know why the controller wants to know the
      > > topology of what it's driving, as long as it's 3-fold symmetric.
      > >
      > > You had me confused with "I'm guessing that the controller was 'smart' and
      > > outputting 2 full power outputs, and 1 low voltage, like it should for
      > > WYE." I'm still confused by that. As you and I both said, all three outputs
      > > should be roughly the same but phase-shifted.
      > >
      > > Yours,
      > >
      > > //Geo
      > >
      > > --- In solectria_ev@yahoogroups.com, "otedawg" <joshua.orfield@> wrote:
      > > >
      > > > Geo,
      > > > Of course I can help out. I didn't know all of this till recently, but I
      > > am a EE and I have worked with power systems, but not motors before.
      > > >
      > > > I guess I'll start with Delta. Simply put, Delta is a motor wired in the
      > > shape of a delta (triangle). The controller outputs the same voltage on all
      > > three posts, and the motor runs in the correct direction based on the
      > > phasing of the wires. A 156V delta 3 phase system runs the 3 points of the
      > > triangle at a total of 78V to ground, and 156V across for phase A-B, B-C, &
      > > C-A. Phase: A is at 0degrees, B is at 120degrees, and C is at 240degrees.
      > > >
      > > > A WYE or Y motor is wired in the shape of a Y (hence the name). To
      > > control this motor, the controller runs similarly, but the voltage across
      > > each leg of the Y motor is lowered. (After EE magic, that number is 1.73).
      > > >
      > > > I'm not sure if I've explained or obfuscated the issue there. You've got
      > > to wrap your mind around the fact that there are 3 different voltage
      > > application locations, keep in mind that power is conserved (A delta motor
      > > will have it's current divided by 1.73, but a Y motor will have the voltage
      > > divided by 1.73), and stare at it long enough.
      > > >
      > > > Equations: http://www.watlow.com/reference/equations/0101.cfm
      > > > Motor Depictions: http://www.firstelectricmotor.com/images/motcon9.jpg
      > > >
      > > > Hopefully that's helpful.
      > > >
      > > > Thanks,
      > > > Josh
      > > >
      > > >
      > > >
      > > > --- In solectria_ev@yahoogroups.com, "geo_homsy2" <geo.homsy@> wrote:
      > > > >
      > > > > Hi Josh-
      > > > >
      > > > > question for you: You seem to know how the controller differs in its
      > > drive characteristics when it's configured for delta or for wye. Can you
      > > elucidate that for me, and for the other group members?
      > > > >
      > > > > I would've just assumed symmetric drive in both cases, and that's why
      > > I've never been able to understand WHY the controller has a setting for
      > > delta vs. wye.
      > > > >
      > > > > yours,
      > > > >
      > > > > //Geo
      > > > >
      > > > > --- In solectria_ev@yahoogroups.com, "otedawg" <joshua.orfield@>
      > > wrote:
      > > > > >
      > > > > > I have switched the motor from wye to delta, and back and forth when
      > > I was trying to test it. I'm confident that I've done it right. I even
      > > tested the leads to make sure the labeling is correct. I think that my
      > > problem was the .par file - I'm guessing that the controller was 'smart'
      > > and outputting 2 full power outputs, and 1 low voltage, like it should for
      > > WYE.
      > > > > >
      > > > > > I'm hoping that's the problem.
      > > > > >
      > > > > > Thanks,
      > > > > > Josh
      > > > > >
      > > > > > --- In solectria_ev@yahoogroups.com, Collin Kidder <collink@> wrote:
      > > > > > >
      > > > > > > The parameter file can now be found here:
      > > > > > >
      > > > > > > http://www.kkmfg.com/PAR-10-1631-0007_SO1083.par
      > > > > > >
      > > > > > > As I had mentioned, I went from delta to wye with a car. I got a
      > > new CCS
      > > > > > > and PAR file and I had to open the motor housing and switch around
      > > wires on
      > > > > > > terminals. The motor can be switched from delta to wye and back by
      > > > > > > loosening nuts and moving wires in the motor. Have you done that?
      > > > > > >
      > > > > > > On Wed, Oct 24, 2012 at 12:33 PM, otedawg <joshua.orfield@> wrote:
      > > > > > >
      > > > > > > > **
      > > > > > > >
      > > > > > > >
      > > > > > > > Collin,
      > > > > > > > Thanks for that - I'll try downloading and running with this
      > > file when I
      > > > > > > > get home today... And I just realized that I need the parameter
      > > (.par)
      > > > > > > > file, not the .ccs file. Could you upload such a file? Sorry for
      > > the
      > > > > > > > inconvenience.
      > > > > > > >
      > > > > > > > Hopefully the wye -> delta conversion is just a parameter
      > > change, not
      > > > > > > > something hidden that Azure uses...
      > > > > > > >
      > > > > > > > Thanks,
      > > > > > > > Josh
      > > > > > > >
      > > > > > > >
      > > > > > > >
      > > > > > >
      > > > > > >
      > > > > > > [Non-text portions of this message have been removed]
      > > > > > >
      > > > > >
      > > > >
      > > >
      > >
      > >
      > >
      >
      >
      > [Non-text portions of this message have been removed]
      >




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