My Robotics team can’t find if it is competition legal to modify Vex 393 Motors in the Vex rule’s. We want to take out the PTC in the motor since our motors are getting hot and the PTC turns off the motor.
It is illegal. Teams that are caught with modified motors can be disqualified from a competition. At the larger events robots will be checked for modified motors during inspection.
Here is a post from the head of the GDC explaining this position.
Rule <R15a> states that motors, including their internal PTC, may not be altered from their original state in any way. Some VRC events may choose to conduct PTC Verification Testing using a PTC Authenticator to ensure compliance with Rule <R15> and help establish a fair playing field for all teams. This is the same testing that was done at the 2014 VEX Robotics World Championship. For full details on the testing process and the PTC Authenticator, please visit:
Not all VRC events will be doing this testing; it is up to the Event Partner to determine if they will be doing testing at their event. Failed tests will lead to an event disqualification as per <R22> of the VEX Skyrise Game Manual.
We know that the overwhelming majority of our teams would never even consider partaking in the illegal modification of motors. However we are aware that a small number of teams have been doing this to gain an unfair advantage. Ethical and fair play are central to the ethos of the VEX Robotics Competition, as such we have taken the steps of creating this testing process to help ensure teams are all competing on the same level.