Were trying to put thermal paste on the ptc in our motors. Were worried about the legality of doing so. Any insight would be much appreciated.
My guess would be no. I’m just saying no since I would figure it is considering modifiying the electrics
If you really need to, you can freeze your motors but I’m not sure about thermal paste
But Thermal paste doesn’t modify the electrics in the motor, it modifies the heat dissipation. That rule applies to completely taking the PTC completely out.
We ran the PTC test on two motors one with thermal paste and one without. We found that they both “give up” at the same time, but the main improvement we saw was how fast the motor turned back on. The motor with the thermal paste turns back on almost immediately, while the one without took a little over 30 seconds to turn back on.
I’d still be careful doing this. Yes it would help with recovery, but during a PTC test if the inspector is inexperienced, they may think you have a mod in and request higher authorities. When I’ve done PTC tests I specifically look for a motor “giving up” and then not moving afterwards for a good 5 seconds.
You should probably post this in the Official Q&A so that Karthik can see it and make a ruling. It really isn’t his style to answer questions that aren’t in that thread.
You’re basically accomplishing the same thing as removing a PTC… The function of the PTC is to make sure the motor doesn’t burn itself out permanently. By adding the thermal paste onto the PTC you’ve made it so that no matter how hot the motor gets it will continue to run without allowing itself to cool down.
That’s my understanding of the matter. It may be flawed however.
This is an unofficial view (according to my interpretation of the rules)…
I have bold the parts that are relevant.
So adding thermal paste should be considered as altering it from the original state.
You will need to post your question in the official Q&A if you want Karthik to reply.
On an unrelated note, how would you do a PTC test on a flywheel or a slip gear launcher?
@meng So we can’t re-pack the internal gears with grease either? It had grease originally so I guess if you got it back tot he original state that would probably be OK, but thermal paste is not a part of the original packaging so no go there it would seem.
@ekk to test on a slip gear launcher would be tough as it has other motors helping it too. You could just plug that one motor into a separate power supply and have it be tripped by holding back the slip mechanism. You may need to unhook the rubber bands.
As for flywheels, same deal but hold the flywheel much like they do a drive wheel.
In some cases I see no way around relubricating motors. If it is not allowed to use a different lubricant, then they should at least include some extra lube with the motor. on our shooter, the grease from the motors seems to leak out where the output shaft is. eventually, i would think most of it would leak out and would have to be replaced
Thermal paste on the PTC is definitely illegal.
Oh its wonderful. I’ve had tons of those tests at worlds. The man in a red vex shirt asks you to unplug the motor controller from your cortex, and plugs it into his benchtest. He then asks you to hold down whatever is attached to the motor, and then he proceeds to stall it for several seconds. 
Although this shouldnt cause damage teams that go through 15+ start to get dying drive motors.
It will be interesting to hold the 1:41 gear ratio lift for 15 secs
I have a 75:1… Not sure how that would actually work. 