Wiring diagram for power circuit clockwise and counterclockwise rotation three phase motor.

The three-phase motors rotate clockwise or counterclockwise depending on the sequence of the three phases are provided.

The end of the three phases, which typically are named with English letters R, S, T, is clockwise and the motor to be connected in series with the U, V, W, will turn clockwise. But this is not always correct, because it depends on the manufacturer of the motor,  how has wrapped its coils and the "visual" of each. Besides, there is no right rotation for the motor; depends on the work that we want to achieve.

The change of direction is made in mutual permutation of two of the three phases. The plan change effect is accomplished by swapping the first to the third phase. The same effect can be rotating the second to the third or the first to the second.

A simple plan to control the rotation shown in the second drawing.

Design automation control direction three phase electric motor rotation

To avoid case to arm simultaneously two relays we put in a series on automation so-called latching contacts. Thus if one is armed relay can arm the other, even if pressing the START button, must necessarily be deactivated first reinforced by pressing the stop and then to activate the other. One relay that "latches" the other with a closed contact (normal close NC) to prevent the arm, hence the name of the contact.

This pattern of changing direction is not ideal because it requires the operator's attention to the actual stopping of the motor, wait some time before starting to reverse. Could someone, while the motor turns at once, press the stop and immediately after, without waiting at all, press the START of the other direction, bringing the motor and load abruptly and perhaps dangerous. This can be prevented by addition of another insurance provision.