Full CIM mounted to a 100:1 Banebots

We have 125 lbs robot and trying to winch robot off ground,
We have
1 full CIM also tries 775 pro
100:1 Banebots planetary
2 4 inc drum using 1 inch straps

we can not lift robot off the ground after it winds up and starts to pull the motors overload. Any suggestions

I would suggest using a JVN calculator (it’d be cool if you used mine :slight_smile:) to calculate the gearbox/motor required. I would say your best bet would be lowering the diameter of the pulley. Remember to account for your battery and bumpers in your robot weight.

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Oddly, if I understand OP’s configuration correctly it’s not out of whack…at first blush.

BUT!

Let’s check the motor data on the CIM to see what kind of torque it’s kicking out at 21A. 0.36 Nm is 0.27 foot-pounds, which at 100:1 is 27 foot-pounds at output…which is well within the limits of a 100:1 HD CIM Sport (140 foot-pounds).

BUT!

If the gearbox is getting stalled, a CIM can kick out significantly more torque than a 100:1 CIM Sport can handle. I would check for binding, go with smaller pulleys to reduce the torque needs, shave weight where it’s possible, and verify any ratchet mechanism is getting engaged in the right direction.

A CIM at 100:1 should have a stall torque of 177 ft*lb, and lifting a 125lb robot on a 4" diameter drum should take 125lb * (4in/2) * 1ft/12in = 20.83 ft*lb. It sounds like you should be well within the CIMs capability. Can you post a picture of the climber and electronics?

it had a tough box at first didn’t work but has the 100:1 with 775 under and chain drive to pulley that is 1-1

Maybe need to pull more from the middle of the robot

I read the same thing I wounder if it’s because we are lifting from back of robot.

as you can see ladder is not fully down, we just fold with pneumatic but if poll is unbalanced we hit the ground

By overload do you mean tripping breakers? What power level are you running the motor?

on a 40 amp and no it overloads motor itself or maybe stall is a better description

with the 775 you would actually hear the thermal overload in motor click off

In the programming though are you running it 70, 80,90,100%

100%

Try running it lower, 70 or 80% and with a fresh battery

Okay, looking at that picture, the problem isn’t the motor. At a guess, the problem is that the nylon strap has to go around that hard 90 degree bend in order to pull the climber back. It probably has a ton of friction, and it also has to fight against that surgical tubing. Is there a way that you can put a pulley in there so that the strap isn’t rubbing against the aluminum?

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check your battery level lol

I’m going to agree with @BordomBeThyName that its friction around that corner that’s killing you. At least put something with less friction (e.g. corrogated plastic) there, but if that doesn’t work, reduce the pulley diameter to get a larger force.

Is there flex in the horizontal piece that the straps bend around? If there is, it would confirm the hypothesis from @BordomBeThyName