What are the functions of commonly used relays in the industry?

Relay This type of electrical appliance that is common in the industry, we all know that the relay is an automatic control device that operates according to a specific input signal. There are many types of relays, including intermediate relays, thermal relays, and time relays.

The KM intermediate relay is usually used to transmit signals and control multiple circuits at the same time. It can also be used to directly control small-capacity motors or other electrical actuators. The structure and working principle of the intermediate relay are basically the same as those of the AC contactor. The main difference between the AC contactor and the AC contactor is that the number of contacts is larger, and the contact capacity is small, and only small current can be allowed to pass through. When selecting an intermediate relay, the voltage level and the number of contacts are mainly considered.

The thermal expansion coefficient of the lower layer of the FR thermal relay is large, and the expansion coefficient of the upper layer is small. When the current in the main circuit exceeds the allowable value and the bimetal is heated, the free end of the bimetal is bent upward beyond the pinch plate, and the pinch plate breaks the normally closed contact under the tension of the spring. The contacts are connected to the control circuit of the motor. When the control circuit is disconnected, the coil of the contactor is de-energized and the main circuit of the motor is disconnected.

KT time relay power-on delay Air-type time relay uses air damping to achieve motion delay. After the attraction coil is energized, the armature is sucked down so that there is a distance between the armature and the piston rod. Under the action of the release spring, the piston rod moves downwards. A layer of rubber membrane is fixed on the surface of the umbrella piston. When the piston moves downwards, a thin space of air will be created on the membrane. The piston is under the pressure of the air below and cannot move down quickly. When air enters through the air intake hole, the piston gradually moves down. When moving to the last position, the lever actuates the micro switch. The delay time is the period from when the electromagnet attraction coil is energized to when the microswitch is activated. The delay time can be adjusted by adjusting the screw to adjust the size of the air intake hole.

After the draw coil is de-energized, it is restored by the action of the return spring. Air is rapidly expelled through the vent. This time relay has two delay contacts: one is a normally-closed contact with a time-delayed disconnection, one is a normally-open contact with time-delayed closing, and there are two momentary-action contacts.