Need help with 4 bar

So we decided at the beginning of the year that we wanted a 4 bar. we started off with a 1:7(or 7:1 i forget all the time the one with the most torqe) gear ratio with speed motors. before the competition we put on turbos. That didn’t seem to change anything if anything it just made our lift faster. But lately we only changed out fork mech and now we cant lift more that 20 times or so before our 6 turbo lift motors burn out. I am asking what should i do? i have 2 more turbo motors or should i change them all to speed? Or should i change the gear ratio? Help please.

@Infinity Minus 1 We do use rubber bands. And it fights agents the motors when going down.

Our team uses a 1:5 speed. It works with 6 motors (theoretically with 4) but to play it safe we use 8.

1:5 with 4 motors and a load of rubber bands works well. Generally, use enough rubber bands so you need ~15 motor power to keep the lift down.

I think an 8 motor lift is a waste of motors unless you want to decrease your external ratio as well. Remember by adding more motors, you are just adding more torque. So if you keep the same external ratio and just add more you will not notice a large difference. If you decide you want 8 motors on your lift, you should you will need to find a more efficient external ratio that takes advantage of the increased torque. This requires more experimenting and a lot of work.

Alternatively, I would suggest changing your internal gear ratio to speed. This means you will not have to reconstruct your arm so it’s quicker and easier than adding two more motors. Also, as many others have suggested above, a common ratio is 5:1 (torque). By changing the internal gearing to speed you final ratio should be 4.375:1.

internal ratio (of speed motor) : exteral ratio of 12 tooth gear to 84 tooth gear = 1:1.6:7:1

1:1.6:7:1 = (1/1.6)* (7/1) --convert ratios to fractions

(1/1.6)* (7/1) = (71)/(1.61) – multiply fractions; numerators together and denominators together

(71)/(1.61) = 4.375/1-- simplify

4.375/1 = 4.375:1-- convert fraction back to ratio

4.375:1 which is as close as you can get to 5:1 without changing your external ratio.

Hope this helps :slight_smile:

Are you using a power expander? We were experiencing similar problems with our six bar, and that fixed it

Rubberband the 4 bar