Starting, maintaining, stop, Referred to as a power outage road) A typical control circuit

In automatic control circuit, the start button SB2, stop button SB1 and ac contactor KM form the start, keep, stop ( Referred to as a power outage road) Typical control circuit. Figure 1 - 24 is a commonly used the most simple control circuit. When starting, isolating switch on the QS. Introduction of three-phase power supply, press the start button SB2, contactor KM coil electricity, contactor's main contact closure, motor direct starting operation power supply is connected. At the same time with the normally open SB2 parallel auxiliary contactor KM is closed, the contactor coil of two roads electricity, so, when SB2 reset, KM coil can be still by KM contact continue to electricity, so as to maintain the continuous running of the motor. This depends on the contactor normally open auxiliary contacts and to keep its coil electricity called self-preservation or self-locking function, the pair of self-locking role contact called self-locking contact. To make the motor to stop operation, just press the stop button SB1, will control circuit disconnection, contactor KM power released, KM will always open the main contact of three-phase power cut, the motor to stop running. When the release button SB1 and restore closure, contactor coil can no longer rely on self-locking contact electricity, because the original closed contact already with the power of contactor disconnect. The bartender blackout road achieve continuous operation of the motor control. But some of the production machinery request button is pressed, the motor running, loosen the button, the motor stopped, this is the point of dynamic control. As shown in figure 1 - Figure 25 a. Figure b and c is to realize the dynamic and continuous operation of the circuit.