Re: Door Lock Module (long)

[jtrealty@xxxx]

One thing you must take into account in reedesigning the lock module 
is the inductance it must control ie: the lock solenoids are coils 
which when you try to stop putting electric into them (like when the 
relay contacts open) the coils still have a lot of "electrical 
inertia" re: inductance, so the current will try to continue which 
results in arcing across the contacts. The heat generated will 
eventually weld the contacts unless you oversize the contacts and use 
capacitors to reduce the arcing. Using an undersize circuit breaker is 
a very temporary solution. Circuit breakers must have a margin of 
capacity above what is being used in the circuit (They are not meant 
to be tripped often). They are primaraly used to protect the wiring 
from overheating, not devices. If you find a circuit breaker to work 
at this low (sensitive) level it will eventually get very sensitive 
and start tripping at lower and lower levels so that it won't let the 
coils activate. In cases where you need accurate and sensitive circuit 
tripping you must look for a better solution that a mechanical circuit 
breaker or a fuse, you will need a circuit capable of sensing current 
draw and shuting down the lock module something like used in modern 
amplifiers speaker output circuitry. (This just keeps getting more and 
mote complicated!)
David Teitelbaum
vin 10757



--- In dmcnews@xxxx, dherv10@xxxx wrote:
> Walt and group. Again I'm not making a case to save the door lock 
module, But 
> I finally made mine lock up also and it was in the position of the 
door 
> switch. So, If your carefully you might be able to avoid the 
problem. Also, 
> the smaller circuit breaker played a big part in the module not 
burning up. 
> It tripped very often till I caught it in-between locks and unlocked 
the 
> doors.