On Sun, 18 Sep 2005 11:02:36 -0700, GM wrote:
  
> > From: piclist-bounces@mit.edu 
> > [mailto:piclist-bounces@mit.edu] On Behalf Of Vasile 
Surducan
> > 
> > On 9/16/05, alan smith <micro_eng2@yahoo.com> wrote:
> > > I am looking, and actually prefer a china source 
(lower cost of 
> > > course) for an door solenoid, running on 12VDC 
(well....6VDC is 
> > > preferred but most run 12V I believe).
> > 
> >  12V yes, DC NO. Because of the magnetisation 
problems. All 
> > door locks solenoids are using either AC, either DC 
with 
> > polarity reversal.
> > 
> 
> How do modern automobiles power door solenoids? 
> 
> I have not examined the electrics from a new vehicle, 
but I have had to
> cannibalize parts from (American made) cars made in 
the 70's and 80's,
> and I assure you that they were using unadulterated 
12VDC to power the
> door lock solenoids. Of course, those were simpler 
times with far fewer
> electronic devices in an automobile, and the factories 
were less
> concerned about the sound of OEM audio so things may 
have changed since
> then. That's why I'm asking.

Well the simple answer is that they aren't solenoids!  I 
have one here (as it happens :-) and it's an electric 
motor driving a rack-and-pinion to give the linear 
motion.  

There are just two wires and I wondered how 
sophisticated it was, so I tried it earlier to see if it 
has any sort of limit switch, but no - it draws about 5A 
when the rod is at end of travel, so it seems to be 
purely a motor with nothing else, so they couldn't use 
AC even if they wanted to - drive it one way to lock, 
reverse the current to unlock.

Cheers,


Howard Winter
St.Albans, England


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist