Emil Johnsen said:
I want to run a 3.6V DC motor from a 12V battery. The motor will not run
continously, only 0.5sec at a time with several seconds delay before it will
run again.
Can I do this without damaging the motor?
(I'd like to avoid using a regulator or PWM if possible, also the extra
torque from higher voltage would be useful.)
I haven't tried it, but I would have thought the answer was No. And if
it wasn't for your final proviso, I'd have suggested a simple 12V PWM
approach. Apart from probably minimising risk of motor damage, that
would allow you to secure extra torque.
FWIW, that's what I was considering doing for my curtain controller
(subject of recent threads). That too uses a screwdriver motor and
gearbox. Mine was originally powered by 2.4 V (2 x 12 V Nicads). But
that didn't quite cut the mustard. So I increased it to 3.6 V (with a
permanent trickle charge sourced from an existing convenient 12 V DC
supply). In initial tests that seemed to give too violent an action
(especially dramatic when the curtains opened automatically at dawn
<g>). But it turned out that the necessary longish wiring to the motor
provided sufficient resistance to tame it.
BTW, I originally tried my 2.4 V motor at progressively higher
voltages from my bench power supply, but quit at 6 V.
Did you also consider a limiting microswitch? I'd be interested in
what stall-detection circuitry you are using.