Motor automatic cycle control circuit

In automated production, according to the requirements of the processing technology, the processing process is automatically cycled according to a certain procedure (process step). This type of work is often used in modular machine tools and special machine tools. The automatic process needs to be triggered by conditions. According to different triggering conditions, the automatic control circuit is commonly used in two forms: time control and stroke control. The following figure shows an automatic cycle control circuit controlled by stroke.

Press the start button SB2 or SB3 to start (forward or reverse). For example, after pressing the forward start button SB2, the contactor KM1 is energized and self-locked, and the M1 circuit is connected and drives the workbench to the left until the mechanical collision block presses the travel switch SQ1 to disconnect the forward circuit and the workbench stops moving to the left. At the same time, the normally open contact of SQ1 is closed to energize KM2 and self-protect, connect the reverse circuit, and the motor reverses to drive the workbench to the right. When the mechanical collision block presses the travel switch SQ2 to disconnect the reverse circuit, the workbench stops moving to the right. At the same time, the normally open contact of SQ2 is closed to energize KM1 and self-protect, connect the forward circuit, and the motor rotates forward to drive the workbench to the left, and the automatic cycle is realized in sequence.

In practical applications, for safety reasons, position limit switches SQ3 and SQ4 are generally set. In addition, due to the limited service life, noise and reliability of mechanical travel switches, non-contact proximity switches are increasingly used in modern equipment to replace mechanical travel switches.