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China Relay, Relay Wholesale, Manufacturers

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Basic Info

Product Description

Basic Structure
- The intermediate relay mainly consists of an electromagnetic mechanism and a contact system. The electromagnetic mechanism includes a coil, an iron core, and an armature. When the coil is energized, a magnetic field is generated, magnetizing the iron core and attracting the armature to move. The contact system includes a moving contact and a stationary contact. The movement of the armature causes the moving contact to make or break contact with the stationary contact, thus realizing the on - off of the circuit.
- It generally also includes a housing. The function of the housing is to protect the internal electromagnetic mechanism and contact system and also plays a role of insulation and dust - proof.
Working Principle
- When a certain voltage (such as AC voltage or DC voltage, depending on the type of relay) is applied across the two ends of the coil of the intermediate relay, a current will flow through the coil. According to the law of electromagnetic induction, this current will generate a magnetic field. The magnetic force of the magnetic field causes the armature to act against the reaction force of the spring.
- For example, in a motor - starting circuit controlled by an intermediate relay, when the control signal energizes the relay coil and the armature moves and its contacts close, the main circuit of the motor can be connected and the motor can be started.
Main Functions
- Signal Amplification: In some control circuits, the control signal may be very weak and unable to directly drive the load. The intermediate relay can amplify this weak signal and control a higher - power load through its contacts. For example, the output signal of a small - sized electronic sensor may only have a current of a few milliamperes, which is unable to directly drive a large - sized contactor. At this time, the intermediate relay can amplify this small - current signal and use its contacts to control the coil of the contactor, thus indirectly controlling the large - scale load.
- Signal Conversion: It can achieve the conversion between different signals. For example, it can convert a DC control signal into an AC control signal. In some complex automatic control systems, different devices may use different types of control signals, and the intermediate relay can serve as a bridge for signal conversion.
- Increasing the Points of the Control Circuit: An intermediate relay usually has multiple contacts (normally - open contacts and normally - closed contacts), which can increase the output control points of the control circuit without adding too much complicated wiring. For example, the control system of a device needs to simultaneously control multiple indicator lights and alarms, and the multiple contacts of the intermediate relay can conveniently achieve the control of these devices.
Classification
- Classification by Operating Principle:
  - Electromagnetic Intermediate Relay: This is the most common type, and the contact movement is realized through the action of electromagnetic force. It has a relatively fast action speed and high reliability and is widely used in various electrical control fields.
  - Solid - State Intermediate Relay: This kind of relay has no mechanical moving parts and works based on the switching characteristics of semiconductor devices (such as thyristors, transistors, etc.). The solid - state relay has the advantages of long life and strong anti - interference ability, but its overload capacity is relatively weak and it is more sensitive to environmental factors such as temperature.
- Classification by Power Supply Used:
  - AC Intermediate Relay: It uses AC power as the power supply for the coil and is suitable for AC control circuits. For example, in the AC motor control circuit of some factories, the AC intermediate relay can be conveniently used in cooperation with AC contactors and other equipment.
  - DC Intermediate Relay: Its coil is powered by a DC power supply and is often used in DC control circuits. For example, it plays an important role in the control system of some DC - powered electronic equipment.
Application Areas
- In the field of industrial automation, intermediate relays are used to control various production equipment such as machine tools, conveyor belts, injection - molding machines, etc. In machine - tool control, it can control the feed of cutting tools, the start - stop of motors, etc.
- In the field of building electrical, it is used for elevator control, lighting system control, etc. In the elevator control system, the intermediate relay can control the opening and closing of elevator doors, the ascending and descending of elevator cars, etc.
- In the power system, it is used for the control and protection of substations. It can amplify and convert the signals sent by protection devices, thus realizing the control of circuit breakers and other equipment to ensure the safe operation of the power system.