Incredibly Frustrated - Broken Motors

New to vex. I have 8 kits for 7th graders. Last year we started to play with them but we didn’t use them long. We lost 6 motors.
This year we replaced the motors and We built the basic speed bot and clawbot in 10 weeks.

Of the 32 motors across the 8 kits 4 have broken. They get plugged in and the light doesn’t turn on, they don’t respond to signal. The last four weeks of students trying to build and drive the robots results in a motor dying every week.

I know it isn’t the wire or the brain. I take that same cable and put it in other motors and those motors work. I try other cables and these motors stay broken. I tried waiting 10 min, 24 hours, and a week to see if it was a “cool down” issue and they never turn back on.

Today a robot that worked yesterday was taken off the shelf, put on the floor, turned on and the motor wouldn’t start. Nothing changed other than putting it on and off the shelf. We have NOT ever used the motor in any creative way. We have only build the standard bot, and the only thing they have lifted with the claw bot is empty soda cans. I can’t imagine we broke them by over torquing them.

We don’t have mats and work on the concrete. I would assume this means they are constantly grounded and don’t build up static charge. They sit on cardboard trays on the shelf when not in use.

This is $200 of motors that broke in the first 10 weeks of use. This seems stupid expensive if I have a motor break every week. I contacted vex support and they said the motors are “consumables”.

What do we do about these motors breaking? Do I need to spay the concrete? Do we need to purchase special anti-static gloves for students to wear? Do we need to unplug every motor when not in use? I am at my wits end with almost every week a robot going out of service and having to scramble so students can finish / complete basic coding activities.

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What is the date code of the motors? If they were purchased in late 2022/early 2023 it is possible that the motors have a defect which makes them prone to dying earlier. See this thread for some details:

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I will say also that what you’re mentioning doesn’t sound like a static issue; when motors and/or brain ports are damaged by static typically the result is that the light on the motor will blink periodically. When the light is off completely as you described, generally that means something else has happened.

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Have you emailed VEX support - if these are new motors, they should be under warrantee.

Common issues is to look for bent pins either port or motor.

Does the motor appear when you go to Devices menu on the brain?

Cooling off does not require a week.

I am sure others have more ideas.

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Sounds like they did exactly that and VEX rejected the request.

It seems odd that they would reject the request considering this sounds like a rev10 motor failure, and the timeline lines up for them having had issues from last school year (2022-2023).

If the light is off on the motor, that means it isn’t booting at all there there is no hope of seeing it on the brain.

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First, go through your local EP and/or state rep. They might know someone @ vex.

Secondly, motors DO die and must be budgeted for along with shafts, cut metal, etc. Your failure rate is excessive though. This is not typical… going forward.

Third… and most concerning. If these are the bad batch, and it sounds like they are, then the rest of the set may die an early death also.

Save the old motors. If you’ve got someone going to worlds, take them and maybe they can get swapped there… along with ALL the rest of yours.

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I have students checking the motor version and it looks like half our motors are rev 10.

we found 11 of 28 motors were rev 10. we threw away the first 3 that fully broke and replaced already and the 3 currently broken don’t turn on so I am not sure how to check if they are Rev10.

Rev 10 Motors - VEX Robotics.
“For failed motors
Failed motors will not have a red light on the smart port when connected to a powered V5 Robot Brain.
Locate the date code on your motor (see image to the right).
If the first four digits of the date code is “2143” or higher it is possible that this motor is a rev 10 and can be returned.”

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this is completly normal and hapens to us all the time. the most comon problem is the motors not being all the way plugged in. try using rubber bands to hold the cable into the motors and make sure the cable is pushed all the way into the brain before running a program. the other thing to try is different cables, because more often than not this will fix the motors not getting power at all. also, the motors seem to just burn up after awhile. (we’ve been through 5 on one bot this year, but we also do competitions so we get more use out of them.) if they are motors you use often, the magnetic contacts for the motor could be worn down or have a weakened magnetic force causing the power loss. and for the record, they are stepper motors. hope this helps!

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i would say your problem is probably the cables aren’t plugged in all the way. for the motor itsself, wrqp a rubber band around it, making sure it covers the cable and holds it in as far as it will go. on the brain, make sure the cable is pushed all the way into the port, as if they are not it can lead to power loss or a sketchy conection.

likely rev10 motors, meaning a number of motors under ‘rev10’ have a manufacturing defect where simply put they break super easily. run a rev10 test Rev 10 Motors - VEX Robotics on those motors.

if they are rev10s, fill out this form rev10rma.vex.com and vex will allow return / refund.

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and I need to add, as usual, this applied to motors built during a certain period of time, not all Rev10 motors have the manufacturing defect.

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Please read the thread. And no, they are NOT stepper motors.

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No need to throw them away, VEX will give you a refund after you return it and they inspect it.

I think my boss got vex to take them back. We are sending back 13 of 28 motors. So our semester is over and moving on to other projects

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