🚀 go-pugleaf

Do they use permanent magnet, electric field or AC (induction) motors?

An electric field DC motor might be the easiest, but the field burns up a
couple horsepower sitting there.  That would cut into efficiency a bit.
[Asynchronous] AC motors are a bit harder to generate power from.

The nice thing about a DC motor is you can drive the armature with a big
fucking H bridge, open circuit coasts, forward = accelerate, reverse =
regenerate / reverse.  It's a built in buck-boost.

Tim

--
Deep Fryer: A very philosophical monk.
Website @ http://webpages.charter.net/dawill/tmoranwms

"kevin93" <kevin@whitedigs.com> wrote in message
news:4c286ed5-dd92-4c84-9c4e-81d507289548@q24g2000prf.googlegroups.com...
> On May 18, 9:58 am, JosephKK <quiettechb...@yahoo.com> wrote:
> > On Sat, 17 May 2008 18:58:49 -0700 (PDT), kevin93
> <..>
> > >This is done to maximize efficiency since the mechanical transmission
> > >has an efficiency of 95% or more but the electrical losses through two
> > >motor/generators are about 20%.
> >
> > That is way past remarkably crappy motor and generator efficiencies.
> > Both are typically each 95 to 98 percent efficient.  Hell the antique
> > "Molly Long Legs" topped 99%.
> <...>
>
> I don't know about those you mention but the published peak efficiency
> of the ones in the Prius (including the inverter) are about 93%, put
> two in series and the losses to convert from mechanical energy back to
> mechanical energy when operating at peak efficiency would be about 15%
> - for other operating conditions they can be a lot worse, hence my 20%
> number.
>
> AC Propulsion (www.acpropulsion.com) only claim 91% from battery to
> shaft for their system with 86% with a "road load" (implying an
> average under normal usage).  That is even lower than the Toyota
> figure.
>
> When considering regenerative efficiency the numbers get even worse -
> the battery may only have a 70% efficiency giving only a 50% overall
> energy recovery efficiency.
>
> Undoubtedly the efficiency could be improved but would add weight and
> cost - Toyota and Honda are the only manufacturers with real-world
> experience of producing this class of machines in million unit
> quantities so presumably these designs represent their view of the
> optimum compromise for this application
>
> kevin