Ignoramus8558 wrote:

On Thu, 15 Dec 2005 09:06:21 -0800, Tim Wescott wrote:
snip
Are you driving the gate directly from the motor?


Yes, it is just a little stick on the shaft.


If so you're really not matching the motor's capabilities to the
problem. If you have an old RC servo lying around you could strip
out the electronics and just use the geartrain and arm from that,
with an appropriate resistor to limit the current, of course.


You know, I may be able to just use a little counterweight and reduce
torque requirements to next to nothing. Then this motor and a resistor
would just be perfect. Torque is a non issue, as I am realizing. Sorry
to have brought it up. As long as I limit current and overheating, I
will be perfectly fine.

i

You mentioned using a solenoid earlier. They're terribly inefficient,
but they're generally built for this kind of load. They have lots of
windings that bulk them up and would slow them down if they should go
fast, but give lots of actuating force and a high resistance to limit
current. You may even want to use separate "open" one and "close" ones;
this will let you use two single-acting solenoids and would simplify
your switching.

If you don't already know about it you want to check out Herbach and
Rademan: http://www.herbach.com. They have this kind of stuff cheap.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com