4 Motor Base Drive (Torque or HS)

I’m coming to the VEX Community to try and help out my middle school team. They are trying to determine how to rig up their 4 motor base drive. And yes, they will be staying with 4 motors. They started out with HS motors on a 1:1 ratio. This all worked fine but they would like more speed. They geared the 4 HS motors at 2:1 and picked up speed but they started tripping and stalled during competitions. Their scissor lift may be a little heavy. So their question now is would they benefit from going to 4 Torque motors geared at 2:1? Would they pick up quickness with less chance of stalling?

High-Speed gears are 1.6:1, so HS geared at 2:1 would be 3.2:1
Torque geared at 2:1 would be 2:1 (obviously) This would be a little faster than direct HS, and have a little lower torque. If it doesn’t stall at HS direct, that I would fathom that it would likely won’t for Torque 2:1

They are actually 1:1.6

Huh, TIL

Turbo 1:1 would be a good in between at 2.4:1, and it would be easy to set up.

You would probably be fine with a 4 motor torque then 1:1

They might still stall, though…

It would at least be better then high speed 2:1. Also the external gearing in that setup would add extra friction the 1:1 turbo wouldn’t have.

Guys, you cant put a scissor lift on a four motor turbo drive. Even high speed will probably stall rather easily. I would recommend starting with torque.

@Bryan R is absolutely right, you cant have a 4 turbo drive, I’ve run it a couple times on very light bots and it still stalled in some games. an average DR4B is fine with 1:1 HS, but a heavier scissor will probably require 1:1 torque to be reliable. i generally wouldn’t recommend an external ratio, but if you do plan on keeping that 2:1 ratio, you almost definitely need to use torque, and even then it would probably stall. use this chart to compare different drive ratios. https://image.ibb.co/fLie9G/image.png

Thanks for all of the replies guys. Due to motor and wheel placement they chain motor to wheel so they will have the extra friction even if they go 1:1. They ran 1:1 with HS motors for three tournaments and never had stall problems. Sounds like the 2:1 ratio with the torque motors would give a small increase in speed over the 1:1 HS motors so maybe they will try that.

It seems they may also have had a problem with tripping the cortex as they had all four motors in ports 1-5. They are also going to separate 2 motors off to ports 6-10.

Yes splitting the pull of the motors between twon bridges is a good idea. Another drive setup i use fro m time to time is a 1.5-1(18t-12t) sprocket ratio. This is great cause then i can easliy swope out drive speeds between matches and skills. The torque setting would provide 150 rpm which is lower than 1:1 high speed but high speeds on this ratio give turbo speed with more internal torque.

We use a 4 motor HS 1:1 set up for our base and we’ve had no problems with it burning out during competition; although, it ends up burning out after strenuous work after 8-10 minutes.

They should switch to torque geared motors and 5" wheels, if they can fit.

i suggest keeping the four motor HS drive. improve speed on everything else and lighten weight of the bot.
by…

  • getting rid of unnecessary metal
  • use all aluminum
  • design lighter and more effective systems