Re: (ET) Big day: E-15 back in service.

["Max Hall" <maxmatic gmail com>]

Max here; yep, I'm using a series controller.

 

And YEAH, David Roden, the Curtis wasn't designed for this application. The one SPST switch I had lying around and used for F/R has a center-off position. If you have it in the off position (and thus have no field current) and hit the "throttle," you can push big current through the armature winding unopposed but for what small resistance those fat windings have (and maybe a little inductance, though the Curtis ramps the current). Not good. Your suggestion is right on; first I should have a two-position SPST, and second, I should make it so the first TWITCH of the pedal switches on the field current relay, THEN any further pedal displacement engages the main contactors and then current from the Curtis. (Then, of course, the shut-off will happen in the reverse order... first PWM current goes away, then the contactors open, then the field winding relay opens.)

 

I would have used the Alltrax, as it seems like a great solution, but I didn't happen to have on of those just sitting on my shelf, the way I did the Curtis, a potbox, and a pair of Czonka contactors!

 

On a related subject: I was telling a friend the other day about how the ET manual starts with an electricity/electronics primer. Thirty years later... consumers are expected either get products fixed by someone else, or just toss 'em when they break. The implicit self-reliance in the manual, and the related assumption that these things aren't planned for obsolescence, and the idea that nothing can go wrong with them that the owner can't somehow fix... well, heck. I've said how much I love 'em.

 

Happy holidays, everybody. Here's to a great New Year, too.

-Max

On 12/21/07, David Roden <etpost drmm net> wrote:

On 21 Dec 2007 at 15:39, Pieter Litchfield wrote:

> If I were you (and I'm pretty sure I'm not),
> I might want to think about spending the $$ for an Alltrax
> controller.

Did I misunderstand Pieter's post?  The way I read it, he's using an
electronic controller, but it's a Curtis golf car controller instead of the
Alltrax.  This works, but requires a separate means of control for the motor
field, since the Curtis controllers are (mosty) series motor devices.  The
important thing is to make sure the field is always first on and last off.


David Roden - Akron, Ohio, USA

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