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Unread 02-03-2011, 21:54
LLogan LLogan is offline
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Re: resetting window motor driven arm after each round

Quote:
Originally Posted by Da Kid View Post
does anyone know about a gear box with a wormdrive in it that uses a cim motor? our mentor was thinking about doing this because of the cim motors' strength.
in a related matter, what would the gear ratio need to be for a denso window motor to rotate a 10 lbs, 50 in. arm that extends to 62 in? we want it to not put too much strain so that the thermal breaker doesn't get tripped. we do have a spring on the arm so that makes it a little easier, but what would the gear ratio be without the spring, just to be safe?
Just do the math. 10lb *16oz/1lb * 62in = 9920 oz*in. A window motor's stall torque is 1501 oz*in.

That means you need about a 7:1 reduction with a single window motor. That'll give you an angular velocity of about 12 rpm. You also should design it so that the window motors don't operate at their max stall torque, so you may actually need to increase the reduction some more or add another motor.
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