late van door question

[Rick TYler]

Originally Posted by JKsenior05

We are using the motor to drive a bike chain and pair of gears. We built a fixed posting tower in the front and then attached the pivot point of the arm to the top.
The smaller of the two gears was placed at the bottem and the large at the top. I believe the math with accounting for arm length and tetra weight it came out to be gearing to something like a 1 to 3 or 1 to 4 ratio. Anway we have enough speed and torque to raise a tetra and hold it in place fairly quickly.

We used the same motor with a fairly short arm (around 42 inches, IIRC) driven by sprockets and a chain with a 9:1 reduction. We've never had a problem at all. We calculated that 5:1 would be the minimum reduction we could use with our arm, but chose to go with 9:1 when we decided that speed of arm movement would not be a critical factor in the game.

Depending on your arm length, you may just be over-stressing the motor. Is it too late (Tuesday) to get a bigger sprocket for the top?

Good luck!