Industrial Electrician Practice Test

Swapping any two T-leads, which are the power leads connected to the motor’s winding, effectively changes the phase sequence of the motor's supply. In a 3-phase system, the interaction between the magnetic fields created by the current flowing through these windings determines the direction of rotation. When two of the three leads are swapped, the phase relationship is altered, leading to a reversal in the direction of the rotating magnetic field. This, in turn, causes the motor to rotate in the opposite direction, which is a straightforward and common method used to change the rotation of a 3-phase motor.

Other methods might involve more complex changes, such as varying the frequency, which can be controlled through a variable frequency drive, but this can affect motor speed as well. Adjusting voltage alone does not affect rotation direction; it might change the operating characteristics or efficiency of the motor instead. Reversing current flow is more ambiguous, as it doesn’t directly relate to a specific electrical configuration in a 3-phase system.