Re: (ET) Speed control

["Christopher Zach" <czach computer org>]

Mmm. Does the E12-E20 units also have a transmission?

The "Single speed" thing really isn't that odd, all things considered. When
you mow your lawn with an ICEngine, you basically have to run the engine at
full throttle to keep the blade speed up. Then you're limited to the six
speeds.

Chris

----- Original Message -----
From: "David Roden (Akron OH USA)" <roden ald net>
To: "Elec-trak" <elec-trak cosmos phy tufts edu>
Sent: Wednesday, January 09, 2002 12:47 AM
Subject: Re: (ET) Speed control


> On 7 Jan 2002 at 21:13, Christopher Zach wrote:
>
> > What kind of speed control do the elec-tracs use? Variable volatge on
the
> > field windings? Stepped volatges off the batteries? Big hunking
resistors
> > (I hope not, the waste!)? Primitive pulse based throttle?
>
> Depends on what model.
>
> The E8/10 I believe had ~no~ speed control -- you just turn on the motor
> and when you want to go you engage the clutch.  You get different speeds
> by using a transmission.  This is the way my ER-36 mower is, and it's
> utterly silly.  GE essentially just dropped a motor in place of the
> engine on a gas rider mower, and failed to utilize the motor's great
> advantages -- that it doesn't need to idle, and that it needs less in the
> way of a shiftable transmission (and no reverse gear).
>
> The E12 has 3 speeds.  The first two speeds put big nichrome ribbon
> resistors in series with the armature.  This is similar to old-fashioned
> resistor golf car controllers.
>
> The E15 has 7 speeds derived similarly, but with field weakening for the
> speeds above #3 or #4.
>
> The E20 has 8 speeds and I believe it is similar to the E15, using field
> weakening, though I haven't looked closely at one.  It has a foot pedal
> instead of a hand lever.
>
> There was no battery tapping for speed control (as far as I know), and
> I'm pretty sure neither GE nor WH ever fitted PWM choppers to any model.
>
>
> David Roden - Akron, Ohio, USA
> 1991 Solectria Force 144vac
> 1991 Ford Escort Green/EV 128vdc
> 1979 General Engines ElectroPed 24vdc
> 1970 GE Elec-trak E15 36vdc
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