(ET) AC tractor DC implements ?

[Jim Coate <jbc_lists_NO_REPLY coate org>]

I think we've leaped to apples vs oranges here...

There is no reason why a garden tractor couldn't have a 36 volt pack 
which would provide power to existing DC attachments (like mower deck or 
tiller) and also supply power to a controller which drives an AC motor. 
In fact, I think the Electric Ox may do/have done just that?

Using an AC motor and matching controller does not require jumping to 
high voltages. The choice of AC vs DC and the choice of system voltage 
are separate. I think I've seen 36- or 48- volt AC controllers and 
motors for golf carts, which I suspect use FETs, just like their low 
voltage DC brethren. And as David mentioned, commercial AC applications 
(forklifts, etc) may go up to 72 volts, which still isn't all that high 
a voltage.

At the high voltage end of things, my (previous) factory-built S-10 used 
a 360 volt AC drive which did indeed have IGBT's inside. And if you look 
inside the "Zilla" controller used on high performance DC cars 
(including the electric drag racers) you will also find IGBT's.

AC is trendy, but a well matched DC controller and sep-ex DC motor can 
provide similar performance and features... which is why more sep-ex 
stuff is also in golf carts these days.

And to the original point, if you look at Walt's announcement, METI is 
using "reliable DC motor technology" so no problems with attachments.


JohnR wrote:
> Just need a monster [$$$$] Buck (DC-DC-Down) Converter to run those 
> attachments ...
> ... safety considerations:  trained Forklift repair guys fixing those
> units, versus homeowner fixing 36v Elec-Trak ?

RJ Kanary wrote:
>    The downside of course would be that none of the existing
> attachments will work..........unless there will be dual mode
> controls. {sigh! }

--

Jim Coate, Spencertown, New York

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