1、 Self locking

電動機起動后，松開啟動按鈕，接觸器通過自身常開輔助觸頭而使線圈保持得電的作用稱為自鎖。舉個簡單的例子，想讓電動機長時間轉，不用一直按著啟動按鈕，在不按停止按鈕和電動機不過載的情況下，只需要點擊一下啟動按鈕，電動機就會一直轉。這就是自鎖控制電路使電動機連續運轉的功能，除此之外自鎖控制電路還具有欠壓和失壓(或零壓)保護功能。如下圖所示，當按下啟動按鈕SB2時，接觸器KM1得電吸合，使電動機運轉，同時接觸器常開觸點也閉合，即使是松開了SB2，電動機也會繼續運轉，按下停止按鈕SB1時，電動機停止。

After the motor starts, release the start button, and the contactor keeps the coil energized through its normally open auxiliary contact, which is called self-locking. For a simple example, if you want the motor to run for a long time, you don't have to press the start button all the time. If you don't press the stop button and the motor is not overloaded, you just need to click the start button, and the motor will run all the time. This is the function of the self-locking control circuit to make the motor run continuously. In addition, the self-locking control circuit also has the function of under voltage and loss of voltage (or zero voltage) protection. As shown in the figure below, when the start button SB2 is pressed, the contactor KM1 is powered on to make the motor run. At the same time, the normally open contact of the contactor is closed. Even if SB2 is released, the motor will continue to run. When the stop button SB1 is pressed, the motor stops.

二、互鎖

2、 Interlock

互鎖兩個接觸器通過自身的常閉輔助觸頭，相互使對方不能同時得電的作用稱為互鎖。

Interlocking two contactors through its normally closed auxiliary contact, mutual make each other can not simultaneously power is called interlocking.

1、電氣互鎖是為了保證電氣設備的安 全運行設置的，舉個簡單的例子，當電動機在正轉的時候，如果誤操作會使控制正轉和反轉的接觸器同時吸合，這樣就會造成短路，如果加入了互鎖電路，當電動機正轉的時候，就算是按下了控制反轉的按鈕。

1. Electrical interlock is set to ensure the safe operation of electrical equipment. For a simple example, when the motor is in forward rotation, if the wrong operation will make the contactor controlling forward rotation and reverse rotation pull in at the same time, this will cause a short circuit. If the interlock circuit is added, when the motor is in forward rotation, even if the reverse control button is pressed.

如果正轉接觸器沒有釋放到位，也不會讓電動機反轉。此時，按下按鈕SB3控制電動機反轉的接觸器KM2是不會吸合的。當KM2得電吸合時同理。當按下停止按鈕SB1或者是熱繼電器FR過載時，電動機停止轉動。（在互鎖電路中我們也看到了自鎖）

If the forward contactor is not released in place, it will not reverse the motor. At this time, press the button Sb3 to control the motor reversing contactor km2 will not close. The same is true when km2 is powered on. When the stop button SB1 is pressed or the thermal relay FR is overloaded, the motor stops（ We also see self-locking in interlocking circuit

2、機械互鎖電氣互鎖是當一個接觸器打開的同時斷開了另一個接觸器的線圈電源達到互鎖的目的。一般電氣互鎖是使用接觸器輔助觸點達到互鎖目的，當一個接觸器接通的同時，切斷另一個接觸器的線圈供電回路。

2. Mechanical interlock and electrical interlock is to turn off the coil power supply of another contactor when one contactor is opened to achieve the purpose of interlock. General electrical interlock is to use contactor auxiliary contact to achieve the purpose of interlock. When one contactor is connected, the coil power supply circuit of another contactor is cut off.

機械互鎖就是通過機械部件實現互鎖，比如兩個接觸器不能同時合上，可以通過機械杠桿，使得一個接觸器合上時，另一個接觸器被機械卡住無法合上。

Mechanical interlock is realized by mechanical parts, such as two contactors can not be closed at the same time, through the mechanical lever, so that when one contactor is closed, the other contactor is mechanically stuck and cannot be closed.

電氣互鎖比較容易實現、靈活簡單，互鎖的兩個裝置可在不同位置安裝。機械互鎖可靠性更高，不用擔心誤操作，但比較復雜，有時甚至無法實現。通常互鎖的兩個裝置要在近鄰位置安裝。

The electrical interlock is easy to realize, flexible and simple, and the two interlocking devices can be installed in different positions. Mechanical interlock is more reliable, and there is no need to worry about misoperation, but it is more complex and sometimes can not be realized. Usually, the two interlocking devices should be installed in close proximity.