Re: [DML] Auto Transmission Seal controllers

[Marc Levy <malevy_nj@xxxxxxxxx>]

Thanks for sharing the details Jeff!  Sounds like some nice improvements..  Many of which I considered when I day-dreamed about an improved control unit.  I am glad you did not do a complete re-design with a microcontroller like some have suggested (WAY too complex for this application!!)

One thing I did consider when looking for alternatives for the 2 large switching transistors was the impact some other components would have on the solenoids in the transmission..  

"order of magnitude lower than that of the power transistors" has me a bit concerned.  You say it like it is a good thing, but I am not convinced it is.

Is it possible the original engineers intended to have that additional resistance in (voltage drop across) the transistors?  In my "what if" design (in my head), I decided it was not worth the risk to change the conditions of the switching circuit for the solenoids as I could not predict the long term impact it would have on the physical internals of the transmission, mostly the solenoids themselves.  The added resistance in the circuit due to the transistors may be needed to restrict how much DC current those solenoids can pull.  

Are you trading off heat in the controller box for additional current (and therefore heat) at the solenoids?  I'd rather change the transistor (something I have never needed to do) in the control box than one of those solenoids!



--- On Thu, 12/3/09, Jeff Angwin <jangwin@xxxxxxxxx> wrote:

> From: Jeff Angwin <jangwin@xxxxxxxxx>
> Subject: Re: [DML] Auto Transmission Seal controllers
> Hi Marc:
> 
> My design is mostly the original, but I improved upon it in
> a few ways.
> 
> First, I added a component that conditions the power to the
> board............


------------------------------------

To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/dmcnews/join
    (Yahoo! ID required)

<*> To change settings via email:
    dmcnews-digest@xxxxxxxxxxxxxxx 
    dmcnews-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/