AC, AC, AC, A.C. or a.c. may refer to an abbreviation for something. For example, the abbreviation of academic, the abbreviation of axiom of choice and so on represent different meanings in different situations.

额定电流是指用电设备在额定电压下，按照额定功率运行时的电流。也可定义为电气设备在额定环境条件（环境温度、日照、海拔、安装条件等）下可以长期连续工作的电流。用电器正常工作时的电流不应超过它的额定电流。

Rated current refers to the current when the electrical equipment operates at rated power under rated voltage. It can also be defined as the current that electrical equipment can work continuously for a long time under rated environmental conditions (ambient temperature, sunshine, altitude, installation conditions, etc.). The current of the electrical appliance during normal operation shall not exceed its rated current.

接触器(Contactor)是指工业电中利用线圈流过电流产生磁场，使触头闭合，以达到控制负载的电器，由电磁系统、触头系统和灭弧装置组成。可用作控制工厂设备﹑电热器﹑工作母机和各样电力机组等电力负载，接触器不仅能接通和切断电路，而且还具有低电压释放保护作用。

Contactor refers to an electrical appliance in industrial electricity, which uses the current flowing through the coil to generate a magnetic field and close the contact to control the load. It is composed of electromagnetic system, contact system and arc extinguishing device. It can be used to control power loads such as factory equipment, electric heater, working mother machine and various power units. The contactor can not only connect and cut off the circuit, but also have the function of low voltage release protection.

其原理是当接触器的电磁线圈通电后，会产生很强的磁场，使静铁心产生电磁吸力吸引衔铁，并带动触头动作：常闭触头断开；常开触头闭合，两者是联动的。当线圈断电时，电磁吸力消失，衔铁在释放弹簧的作用下释放，使触头复原：常闭触头闭合；常开触头断开。

The principle is that when the electromagnetic coil of the contactor is energized, a strong magnetic field will be generated, so that the static iron core will generate electromagnetic suction to attract the armature and drive the contact action: the normally closed contact will be disconnected; The normally open contact is closed and the two are linked. When the coil is powered off, the electromagnetic suction disappears, and the armature is released under the action of the release spring to restore the contact: the normally closed contact is closed; The normally open contact is disconnected.