Types of Relays

The types of relays include electromagnetic relays, voltage relays, time relays, pressure relays, thermal relays, overvoltage relays, static voltage relays, hot wire relays, solid state relays, and thermal reed relays.

Types of Relays

Electromagnetic relay

Electromagnetic relay is an electronic control device. It has a control system and a controlled system. It is usually used in automatic control circuits. It actually uses smaller current and lower voltage to control larger current and higher voltage. A kind of "automatic switch", so it plays the role of automatic adjustment, safety protection, conversion circuit and so on in the circuit.

voltage relay

Voltage relay is an electronic control device, which has a control system and a controlled system. It is usually used in automatic control circuits. It is actually an "automatic switch" that uses a smaller current to control a larger current.

Time Relay

Time relay refers to a kind of relay whose output circuit needs to go through a specified accurate time to produce a jumping change after adding an input action signal. Electrical components that switch on or off circuits with higher voltage and higher current.

pressure switch

The pressure relay is a component in the hydraulic system that makes the electric contact act when the fluid pressure reaches a predetermined value. The pressure relay can also be defined as a hydraulic component that converts pressure into an electrical signal. It can be adjusted according to its own pressure design needs. , to realize the function of outputting an electrical signal at a certain set pressure.

thermal relay

The working principle of the thermal relay is that the current flowing into the heating element generates heat, which causes the bimetal sheets with different expansion coefficients to deform. When the deformation reaches a certain distance, the connecting rod is pushed to disconnect the control circuit, so that the contactor When the power is lost, the main circuit is disconnected to realize the overload protection of the motor.

overvoltage relay

The overvoltage relay is a relay that operates according to the voltage value. When the input voltage value reaches the set voltage, its contacts will act accordingly.

static voltage relay

Static voltage relays are divided into protruding fixed structure, protruding plug-in structure, embedded plug-in structure, RY-D series guide rail structure, etc., and have a transparent plastic cover, which is set with a thin code.

hot wire relay

The hot wire relay is an electrical appliance that turns on or off the controlled output circuit when the input quantity (such as voltage, current, temperature, etc.) reaches a specified value, and can be divided into electrical quantities (such as current, voltage, frequency, power, etc.) There are two types of relays and non-electrical quantities (such as temperature, pressure, speed, etc.) relays.

solid state relay

A solid-state relay is a four-terminal device with two terminals as input terminals and the other two terminals as output terminals. An isolation device is used in the middle to realize electrical isolation of input and output. Solid-state relays can be divided into AC type and DC type according to the type of load power supply. .

Thermal Reed Relay

Thermal reed relay is a new type of thermal switch that uses thermal magnetic materials to detect and control temperature. It is composed of temperature-sensitive magnetic ring, constant magnetic ring, reed switch, heat-conducting mounting sheet, plastic substrate and other accessories. , The thermal reed relay does not use coil excitation, but the magnetic force generated by the constant magnetic ring drives the switch action.

Introduction to Relays

The relay is a kind of electric control device. When the change of the input quantity meets the specified requirements, it is an electrical appliance that causes the controlled quantity to undergo a predetermined step change in the electrical output circuit. The relay has a control system and a controlled system. It is usually used In the automatic control circuit, it plays the role of automatic adjustment, safety protection, conversion circuit, etc. in the circuit.

The principle of the relay

When the switch of the low-voltage relay circuit is closed, a current will flow in the relay coil, and the iron core in the coil will generate electromagnetic attraction force, and the armature will overcome the tension of the spring under the action of the electromagnetic attraction force and attract the iron core, at the same time The switch piece at the far end of the armature will be closed with the switch contact of the high-voltage circuit, and the high-voltage circuit will be turned on. When the switch of the low-voltage relay circuit is disconnected, the armature will be away from the iron core under the tension of the spring, and the switch piece at the far end will be at the same time. The switch contacts of the high-voltage circuit are disconnected, and the high-voltage circuit is disconnected.

The role of the relay

The role of the relay is to expand the control range: for example, when the control signal of the multi-contact relay reaches a certain value, it can switch, break, and connect multiple circuits at the same time according to the different forms of the contact group; amplification: for example, sensitive type Relays, intermediate relays, etc., can control large-power circuits with a very small amount of control; integrated signals: for example, when multiple control signals are input into multi-winding relays in a prescribed form, they are compared and integrated to achieve predetermined control Effect; automatic, remote control, monitoring: For example, the relay on the automatic device, together with other electrical appliances, can form a program control circuit to realize automatic operation.