I had a question about y cable as i was looking through the rule book. I am planning on using 12 motors but i came upon this rule.
<R12> A maximum of one (1) VEX Y-cable can be used per Motor Port of the Microcontroller or
Power Expander. (You cannot “Y off a Y” to have more than two (2) motors controlled by the same
Motor Port.)
So theoretically i need 2 y cables in order for me to use 12 motors. but because of this rule i cannot. Can anybody clarify rule.
p.s. does anybody know if the power sent to the motors cuts in half if i use a y cable for 2 motors?\
Also, y cables do not reduce the amperage going into each motor (ignoring resistance, which increases). Instead, the motors draw more current from the same motor port. Be careful not to overload the Cortex’s 4 amp circuit breakers. There are two of them, for ports 1-5 and 6-10. 393 motors can trip them, even without y cables, if 4 of them are under heavy loads at the same time and on the same breaker. My team always puts 2 motors of our drive on each circuit, and 2 motors of the lift/flywheel/other scoring mechanism on each one. This way, if one mechanism places heavy load on the motors, such as a flywheel, it doesn’t trip the circuit breaker and reset the Cortex in the middle of a match. An example of this being useful is on our robot this year. When our flywheel first begins to spin up, the motors briefly draw so much current from the Cortex that the LCD screen shuts off. At least, it did last month, I haven’t checked since then, and we’ve rebuilt it, so it might be better now. The only reason the Cortex continues to work while the flywheel spins up is that only about 2-3 amps are drawn from each circuit, and that’s not quite enough to trip the breaker.