Window Motor will not lift ball anymore. It did, but it wont any more.

[ShaneKent253]

Hello from team 253!

We have a window motor lifting a claw that extends out of our frame roughly 19". Last week it worked fine running directly off of a spike and now we just cant get the claw to lift even though we haven't changed a single thing.

I don't know what to do and I am feeling a lot of stress about the situation. Any help would be appreciated.

Thank you!

Shane

Pictures coming.

[Chris is me]

Are you gearing the arm directly to the window motor? This is bad bad bad. You need at the very least a healthy sprocket reduction.

When we used window motors on our 2011 arm, even with a reduction and counterbalancing the motors would wear out about once per regional. Basically they would get very hot and then just stop working like yours seems to have. I would not do a window motor arm again unless it was very short and / or a ton of reduction was added to the motor.

With the high number of COTS gearboxes that are available to accomplish high reductions, you have a number of other options to consider that use a higher power motor more safely. You will likely need to combine products (e.g. a VersaPlanetary + a spur gearbox) but it's very doable.s

[ShaneKent253]

Here is a picture of our motor. This motor is brand new and it still wont work again. Can you think if there is any reason that a brand new motor wont work any more?

Thanks.

[ehfeinberg]

Does the motor still spin in a no load application? (Not having to lift the entire arm assembly?)

[ninjabaker2395]

Originally Posted by ShaneKent253

Hello from team 253!

We have a window motor lifting a claw that extends out of our frame roughly 19". Last week it worked fine running directly off of a spike and now we just cant get the claw to lift even though we haven't changed a single thing.

I don't know what to do and I am feeling a lot of stress about the situation. Any help would be appreciated.

Thank you!

Shane

Pictures coming.

from what you described it sounds like you stripped the main gear of the motor. The same happened to my team2395 in 2012 on our bridge manipulator. You either have to change out the gear or replace the entire window motor, but that will be a temporary fix because it will strip again if you don't change the way in which you rotate the shaft.

[James Tonthat]

Does the motor make any noise at all? Did you burn out the 20A fuse in the Spike?

[ShaneKent253]

The fuse is brand new and so is the window motor.

[ShaneKent253]

In a no load application where we are only lifting our arm assembly without the ball the motor works fine. Only when we try to lift with the ball does the window motor not work.

Any ideas?

[Chris_Ely]

Originally Posted by ShaneKent253

In a no load application where we are only lifting our arm assembly without the ball the motor works fine. Only when we try to lift with the ball does the window motor not work.

Any ideas?

The window motor has an internal thermal breaker in it which opens to prevent the motor from burning out. It appears that you have the motor attached directly to the pivot of the arm. This will place a large load on the motor. When the ball is added, the motor stalls, and the internal breaker trips.
Try using a different motor, and using a gear/chain/belt reduction before the arm.

[ShaneKent253]

Originally Posted by luckof13

The window motor has an internal thermal breaker in it which opens to prevent the motor from burning out. It appears that you have the motor attached directly to the pivot of the arm. This will place a large load on the motor. When the ball is added, the motor stalls, and the internal breaker trips.
Try using a different motor, and using a gear/chain/belt reduction before the arm.

Would it be plausible to use a pnuematic piston on a cam system. By my knowledge it wouldn't have to be a large piston, it would just have to apply enough force to lift the ball.

[nicholsjj]

Did you take the internal safety lock pins out?

[ShaneKent253]

Originally Posted by nicholsjj

Did you take the internal safety lock pins out?

No, but I have heard about this. Can you explain what this would do for us?

[Chris_Ely]

Originally Posted by ShaneKent253

Would it be plausible to use a pneumatic piston on a cam system. By my knowledge it wouldn't have to be a large piston, it would just have to apply enough force to lift the ball.

That could be possible. It depends on what you are trying to do. A pneumatic cylinder only has two positions, in and out. If that is all you need, then it could work. You will have to do the calculations to determine how large a cylinder you need.

[nicholsjj]

Originally Posted by ShaneKent253

No, but I have heard about this. Can you explain what this would do for us?

http://www.chiefdelphi.com/media/papers/2685? This is a paper on how to take them out. From my limited understanding of what happens is that they will lock the system up if they are put under too much stress, such as lifting a heavy arm. This is added to them as a saftey feature so that children or adults do not break their fingers in a jamed car window I think. We had trouble at first with them last year as we used 4 windowmotor gearboxes for our climber. If you arm is lifiting and then all of a sudden stops then I would look into taking them out. It is legal to do still by R30 in the rules. If you are still having problems you can machine out another motors output shaft and attach it to the window motor gearbox leagly per Q&A 243.

[Chris is me]

You definitely can't get away with directly driving an arm with a window motor. You need a reduction of some kind.

If you can make pneumatics work for you, I would suggest that simply because it's much easier to accomplish and simpler than a motor driven arm system.