[NSRCA-discussion] Electric vs. Glow

[Ed Alt]

Bob:
The faster the prop turns in a freewheeling mode, the more braking effect, so the less load on it from expending energy into a load, the faster it will turn.  When you have an electrical generator being propelled by some force and the voltage generated from the windings is not connected to an external load, then no current other than eddy currents is going to flow in the motor, which ought to be fairly insignificant.  So there is an EMF, but no significant power generated by the motor windings when being driven by an external mechanical force when there is an incomplete circuit from the windings into any external electrical load.  

Ed
  ----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Sunday, February 19, 2006 9:29 AM
  Subject: Re: [NSRCA-discussion] Electric vs. Glow


  Maybe I'm not understanding what you are saying. Regenerative braking would cause less downline braking than a freewheeling motor?

  If you are comparing regenerative braking with non-regenerative braking, I would think the motor would heat less, since with non-regenerative braking the motor windings ARE the load, are they not?

  Bob R.


  Ed Alt <ed_alt at hotmail.com> wrote:
    Also, though it's a great thing if it can be implemented well, regenerative braking will contribute to heating of the motor and it may actually reduce the downline braking effect somewhat.  If you don't dissipate the energy into a load, the motor will spin at a higher RPM while windmilling, effectively incr! easing the disc area and allowing it to cool a little bit on downlines.  Re heating, when a load is applied (the battery under charge in  this case), the voltage generated by the motor windings now results in a fairly significant current flow (no, or very little flow happens without the charge path closed).  This will result in electrical power being dissipated in the windings, therefore heating will occur on a downline, not cooling.  Also, since the battery is already running warm, it may not be very good for it to get these brief and relatively large charging currents.  Not sure how bad that effect may be, but it's got to get evaluated by a battey expert.  Sure would be good to solve the problem and keep everything within safe parameters though.

    Ed



------------------------------------------------------------------------------


  _______________________________________________
  NSRCA-discussion mailing list
  NSRCA-discussion at lists.nsrca.org
  http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.nsrca.org/pipermail/nsrca-discussion/attachments/20060219/84b26aaa/attachment-0001.html