This is a continuation of
I thought that CB-1 was mainly a heat-sensing circuit breaker which was mounted on the outside of the main motor to trip at some high motor temperature cutting the current to everything including the PTO. My only reference was Page 6-7 in the manual which reads that the difference in the E20 over the E15 is the “physical size, available torque, the heat-sensing circuit breaker, and the field connection plug.” With that in mind I decided to shorten the leads to the motor which probably was wrong and based on your comments I will now undo and connect as the original schematic shows. I may buy some better wire one day as you have but not now. Thank you for pointing out that CB-1 is a Klixon and primarily an over current device to protect the armature. You’re wide awake! Raymon
I'm a little confused as to why you think the PTO circuit should be protected by CB-1? My guess is that since you are not using it to protect armature current, you figured you might as well use it someplace, huh?
To my knowledge, the PTO circuits of all the tractor's schematics I have seen have had no overload protection. A mower deck is the only thing I have ever plugged into the PTO receptacle and each motor has it's own circuit breaker. Since I have never messed with them, I'm not sure if the motors on the tiller or snow blower have their own built-in breakers or not.
I don't know if you have an early or late model E20, but in either case as originally wired, if the drive motor armature current draw was ever high enough to trip CB-1, then the entire control circuit, including the PTO contactor's coil, would drop out. Keep in mind that CB-1, the Klixon breaker mounted on the outside of the motor, is primarily an over current device for armature current. CB-3, located inside the motor, is an over temperature device.
With my current wiring diagram, if the small thermal overload inside the drive motor (CB-3) opens up, it would cause the PTO coil and the Alltrax control circuit (via the Main Contactor coil circuit) to drop out. I'm not positive, but if we ever got into a situation where the drive motor armature was drawing so much current that it kicked out CB-1, then internally the motor was probably getting hot enough to kick out CB-3 also. Maybe GE figured that if we abused the drive motor, either it would draw too much current and trip CB-1 or get too hot and trip CB-3. Either way, with the original wiring, the tractor would essentially shut down and so will mine.
The original high current wiring was #6 stranded copper. It was small (easy to run) and cheap, but in my opinion it was marginal with respect to current carrying capability and minimal voltage drop. As I have already stated, I'm replacing all that with #2 welding cable, but #4 welding cable would be a good choice also. Welding cable is relatively flexible and fairly easy to route through the tractor.
As for Steve wanting your 250 amp ANN fuse in the B- line, that makes sense. As you said, all power must go through that line to get back to the negative side of the battery pack, so maybe you don't need CB-1. I think I will keep CB-1 in one of the leads to the armature just as additional protection, but I will move my 200 amp ANN fuse to the B- line instead of the B+ line. I think I'd rather kick the 105 amp CB-1 instead of blowing a rather expensive ANN fuse and having to replace it. Give it a little time and CB-1 will reset itself and I might be able to drive back to the house.