<VV> Re: TONNAGE no internal combustion Corvair

[TiM M]

Hey Frank,
     I'm running an Advanced DC 9" motor. Yes, the
motor will slow the truck if I put a load across it,
the problem lies with the brush timing. To turn the
motor into a generator the brushes have to be retarded
in order to eliminate arcing which will burn up the
brushes and the commutator. The modern AC powered car
sized motors have three phases and the timing is
controlled electronically so regenerative braking is
easy. There are a few schemes out there to make a
movable DC brush rigging, but it's complicated and not
easily implemented.

TiM

'61 Electric Rampside

--- Frank DuVal <corvairduval at cox.net> wrote:

> 
> What type of DC motor are you running?
> 
>  From a motor standpoint, you have your terms
> backwards.
> Induction AC motors, the most common, are the ones
> that don't 
> regenerative brake well, because they do not act as
> alternators. Most DC 
> motors will act as generators, therefore can
> regenerative brake.  For an 
> AC motor to be used for regenerative braking, it
> typically would be a 
> synchronus motor with brushes. Just like a Corvair
> alternator.
> 
> Regenerative braking is just placing a load across
> the motor terminals 
> while the motor acts as a generator. The ability to
> do useable work 
> (like charge a battery)  with an AC motor just
> became possible easily 
> with newer electronic methods because of the varying
> frequency of the AC 
> motor output as speed changes. DC just needed to be
> a higher voltage 
> output than the battery that needed charging.
> 
> Just play electric street car with your rampy and
> place a load across 
> your DC motor terminals when you need to brake. Yes
> you need to 
> dissapate heat, but better than dissapating it with
> brake shoes and drums.
> 
> Frank DuVal
> 
> 
> TiM M wrote:
> 
> >     Unfortunately my truck doesn't have
> regenerative
> >braking. Lifting my foot off the pedal is the
> >equivalent of shifting into neutral, it only slows
> >down if I'm going up hill. It's very difficult to
> >implement regenerative braking on a DC motor, it
> comes
> >naturally to a AC motor, but they cost more.
> >     Fading could be a problem, I'm probably going
> to
> >go with Kevlar shoes when these wear out. I try to
> >avoid as many big hills as I can, too much power to
> >climb them, then I toast the brakes on the other
> side.
> >     Being electric it's much easier on the clutch.
> I
> >put it in gear and release the clutch before I
> apply
> >power. The only time the clutch slips is when I hit
> >the pedal too hard from a stop while leaving it in
> >third. I figure this is my safety release that
> >preserves the rear end and axles. ;-)
> >
> >TiM
> >
> >'61 Electric Rampside
> >
> >  
> >
> 


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