Cim-Sim gearbox for shooter questions

[Kevin Sevcik]

Originally Posted by RoboCat2005

Thanks we worked hard on the system for getting over, we based it on the NASA Rocker Bogie system.
To answer the questions:
-2 Fisher Price motors
-Started with 6" now has a 4" in it
-With the 6" it had about an 1.5" almost 2" of compression, although it happens early and the exit is a little less then at the beginning.
-it bogs the motors down quite a bit as the ball drops in
-Each motor is hooked up to a jag each and the motors run at full speed when the ball is introduced.

If you're only running about 0.5 to 1" of compression now, you really shouldn't be bogging those motors down, even if those are the weaker FPs. You really shouldn't be having problems if you have 0673 FPs. Do you have any guess how much current the motors are pulling when it's running without any balls? It should be something less than 10 amps. Anything more means you have some serious mechanical binding somewhere.

Frankly, your system looks like it should manage better than a foot or two. I'm leaning towards there being some significant mechanical resistance somewhere in your system. Your sprocket-chain connect there is a possibility. I'd also look at your bearing system for the axle of those shooter wheels and make sure you don't have any resistance anywhere. Some of my kids had a shaft collar rubbing against an aluminum retaining plate. It warmed up the shaft nicely and also slowed done the shooter a good bit.


I guess the other thing I would do is make sure both motors are actually running and pushing the shooter in the right direction. You can check that by unplugging one of the motors at a time and making sure the wheel still turns and in the correct direction.

EDIT: Now that I see you're runnig the new 170W FPs, you might as well swap those out for a pair of the BaneBots RS-550 motors. Those are 250ish watts but otherwise physically identical to the FP motors. That'll atleast give you a little more speed and torque.