Power Problems?

My team built a scissor lift but when it lifts it go up then jam when we try to go down.However if we wait a couple of seconds the problems the problem fixes itself.The problem will comeback when i try to go back up directly after the lift goes down.

Its almost as if it is recharging.

Any idea how to fix this
Please respond quickly as we have to pack the bot for TSA nationals


When you say jam, do you mean that the linear slides/joints are binding up from friction? In other words is the lift physically stuck in place or could you easily lower it with your hands?

If the lift isn’t stuck then it sounds like your motors are just overheating, that would give it the “recharging” feel.

Either way you want to reduce friction. Are you lubricating your linear slides?

It sounds like you are tripping the over current protection in the motors.

How many motors are you using? What’s the gear ratio?

When it gets jammed we can easily push it down by hand
I dont know what the the gear ratio is but i have two motors (one on each side) which are connected to motors that rotate along stationary motors

Could you post a picture of the motors/gearing then if you don’t know the gear ratio?

If you are only using two motors you need a pretty large gear ratio (at least 1:7 probably more).

Here you go on both sides

Ok, so 1:1 ratio as the gears are the same size. You probably need to use a smaller gear on the motor side.

thanks i will have to try that

Yes, go with a 12 tooth metal gear to get a 5:1 ratio. Next thing is lok at friction and pulling forces of the rubber bands as you come down.

Are those rubber bands connected to the square shaft acting as the axle? That could be causing it to bend and give you some friction. Try making one of the bearing block screws longer and attaching there.

The amount of rubber bands could be hindering your decent too. It takes more force to get to the bottom as the rubber band stretches.

Lastly, look for friction points on the bottom rail. In gateway, we had the new linear sliders and eyelets to avoid metal on metal contact.

If that doesn’t work I would try a 7-1 gear ratio.
If that doesn’t I don’t know what to tell you.:frowning:

if 7:1 doesn’t work, go higher. Gear your lift as high as you think you’ll need.