So, we have two CIMs hooked up to an AM ToughBox. This is driving a pulley with a cable, lifting up a lift. Lots of torque, but not too much.
The first time you lift the lift, it goes up nice and smoothly. No motor noise.
The second time you lift the lift, the motors start making a terrible vibrating sound, almost as if they are being stalled. Increasing the speed reduces the noise, and at full speed there is no noise (but we would NEVER want to lift our lift at full speed.)
If you let it sit for about 10 minutes (I’m assuming the motor ‘cools’, or something to that effect), and try it again, on the first lift, there is no noise again.
Any Thoughts? (I can provide torque values if required.)
Are you sure that the vibrating is an issue? We have a 4CIM drive train and it makes a lot of noise on one side due to our plates being different sizes, so the gears don’t mesh as well as they should. You may want to check that.
It very well could be heating/cooling. The AM Toughbox has a lexan backplate, and plastics are known for having high coefficients of thermal expansion. It could very well be that you’re heating that plate up.
If you continue to have problems, you can try making a new back plate for the Toughbox out of a stronger material (like a plate of 1/8" (or holey 1/4") aluminum).
If that’s the case the friction for the heat must be coming from the gear boxes, By the time the CIMS get hot on the outside, they’re really hot on the inside.
The problem may not be in your motors.
Make sure there is a low amount of friction on your sliding device for upward travel. If it is metal on metal white lithium grease would work well, but requires maintenance and can be messy if you over apply.
If it is 80-20 with those nylon slide plates (which my money for no apparent reason is on) you have to check and see what will affect the nylon. I think the white lithium would work there too.
All speculation
all assumptions
but one big hunch
won’t hurt to check it out
Are the two Victors driving the CIMs driven by a Y-cable? You might try calibrating the Victors again using the same joystick to make sure the motors aren’t backdriving each other a little bit. I say this because PWM variability can be the worst at the lower speeds, and you said it vibrated more at lower speeds.