Drive Dying

Our drive is completely normal when we try to move forwards and backwards, but when we turn, the front two motors turn really slowly and die it in about 10 seconds.
We use a direct 4 motor highspeed drive on 4" omni-wheels.
Here is our code for our arcade drivem, the left two motors are y cabled and the right two are y cabled as well:

motor[LeftD] = (vexRT[Ch3] - vexRT[Ch1]);
motor[RightD] = (vexRT[Ch3] + vexRT[Ch1]);

Thanks in advance!


Is it only the front two motors that are dying? That would indicate to me motor troubles-- you could try switching out the motors and see what happens. It’s also worth changing out the motor controllers.

If that doesn’t work, my best guess is that a PTC fuse (on the cortex) is getting tripped because your motors draw too much current during turning. It often happens with heavy robots. The motor power ports on the cortex have 2 PTC fuses, one for ports 2-5, and one for 6-9. They trip at around 4 amps. The motors will usually trip a fuse before they stall. So if both Y cables are drawing power through the same fuse, they’re more likely to get tripped. Try powering one on ports 2-5, the other on ports 6-9. Or you could power your drive with a power expander (if you’ve got one). I believe those have their own fuses. Also it could be that HS gearing is the problem, because that will demand more power.

Hope this helps!