Broken V5 Motor... Again

Yes, yet again I have a burnt out V5 motor. This time from my puncher, I have 2 HS motors on there, and the primary one that’s connected to the slip gear, has died. About 15 seconds before it did, I shot a ball at my brother, which worked fine (Don’t worry, he was aware). We did it again, only the motor just died. After some troubleshooting, it is not the port, wire, or code, it is 100% the motor. It still lights up, occasionally flashing very fast, and recognizes that the command is -200rpm, and on the brain, says that as well as 0 rpm for the part that shows the actual speed of the motor. Any ideas how to fix this? I’ve redownloaded code, etc, but nothing seems to be working

EDIT: After new tests, changing port doesn’t work, either. This time its not buzzing either, its dead silent, and, well, its dead.

can you manually turn the motor? can you tell if the motor is physically broken, or if its something like the port on it that’s damaged?

@Xenon I havent tried with my hand, but the secondary motor that goes with it is able to move it, so i assume my hand can too

Contact VeX ASAP. They are well aware that some of the motors are just not up to the task. we’ve had a continual problem with ours. It is frustrating. :confused:

This seems like an electronics issue. We’ve had two motors fail, both in what seems to be the same way. The brush/commutator bit appeared to melt. The thing we noticed with ours is the sound from the motor. When we fully disassembled the casing, and removed the motor from the board (it snaps in) it made rattling noises. We decided to then take it apart (I don’t recommend if you want a replacement), and there was a solder blob, along with (what I assume to be) the commutator (which fell off when barely touched after removing the armature) with some blobs of solder on it, like it melted during operation. Here are some microscope pictures of the motor:

I am by no means a expert on Brushed DC motors, so I may be interpreting this wrong, but in my case it looked like an overtemperature issue. This was because it has a physical limit and was trying to reach a value it never could. It never burned out, just continued going until its death.

Were you trying to make the motor rotate for a certain distance, or using constant power?

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Constant power for a puncher. it was the motor connected to the slip gear.

PS: Your images are not working, try putting them in a google drive and sharing the link?

That’s probably your problem. You should either remove the brake hold(or constant power), and replace it with a ratchet. The motor must be overheating, and the firmware isn’t stopping it from dying.

oh apologies, misunderstood. its NOT constant, its on the coast brake type

It has to be a problem with your puncher. I see no other reason why two motors would die in the same application. Did you follow the 574C puncher tutorial?

we did not. only one motor died, the other (chained to it) is fine. one of the two motors that died were on our drivetrain, no idea why though. our puncher is a bit… shady to our secondary motor, but that one isnt dead

your… puncher… is chained…?

ask no questions… my teammate chained the two motors together, i tried to convince them to use gears, but alas, no success. if i have time i will probably change it since we’re losing a lot of power, but i dont think thats why the motor died

I think that is partially why it died. you were overpowering the single motor and the second one wasn’t able to assist it because of the chain. I could easily be wrong, but If it had been geared I dont think the motor would have been lost.

ok, thank you! ill use that as my point to convince my team to change it haha

I wonder if there needs to be some kind of thermal pad between the motor and the pcb? From my own testing there seems to be some kind of low-res temp sensor on the PCB opposite of the motor. If the motor pulls away from the PCB slightly, it might not transfer heat effectively enough to the temperature sensor to trigger throttling.

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this would be a good idea.

i love computers, and have built my own, and every pcb i used had thermal pads or paste of some sort. Itll help with heat transfer, and maybe make the vents actually BE vents? will help with overheating and heat detection, no reason for a motor that will be stressed and hot to not have overkill heat dissipation

While thermal pads between the motor and the casing would be beneficial, I don’t think it will happen because of increased assembly costs and complexity.

haha we can dream