What is the correct way of grounding single phase motor frame if I have to choose between two options:
(1) Short to earth connection: from the frame to nearest grounding rod. See below the schematic. (2) Long to earth connection: from the frame to the ground bus power panel that the motor is supplied by (which could be just far away. See below.
I think (1) is not enough since it does not have a fault current path with the neutral if the hot conductor (s) energizes the frame.
I see the fault current path as a way to trip the breaker or the fuse
However, I just do not understand why this is not the case with 3 phase motors
In 3 phase motors, you don't usually have a neutral, and if the frame is energized, then how will the trip happen ?