Relay working principle and characteristics (Dieselpartsworld) 2016-01-19     

Relay working principle and characteristics
1. The working principle and characteristics of electromagnetic relay
Electromagnetic relay is generally composed of iron core, coil, armature, contact etc..
As long as the coil ends with a certain voltage, coil current will flow through certain, resulting in electromagnetic effect, keeper will attract the electromagnetic force to overcome the tension of the spring to return to the core aspiration, thereby driving the keeper of the moving contact and stationary contact (normally open contacts) pull.
When the coil power, the electromagnetic suction disappeared, the armature will be in the spring reaction force to return to its original position, the dynamic contact with the original static contact (normally closed contact) release. This pull and release, in order to achieve the circuit in conducting cutting purposes.
For relay "normally open and normal closed contacts, it can be to distinguish between: relay coil is not energized in the disconnected state of static contact, known as the" normally open contact "; in connected to the state of the static contact is called" normally closed contact ".
Relay input signal x from zero continuous increase reached armature began to pull the action value XX, relay output signal immediately from = jump to y=ym, is often open contact from off to pass.
Once the contact is closed, the input amount of X continues to increase, the output signal of Y will no longer change. When the amount of X is decreased from a certain XX value to XF, the relay starts to release, and the normally open contact is disconnected. This characteristic of the relay is called the relay characteristics, and also the input and output characteristics of the relay.
The ratio of the release value XF to the action value XX is called the feedback coefficient, that is, XF /xx Kf=
The control power output from the contact point is Pc and the minimum power P0 absorbed by the coil is called the control factor of the relay, i.e., Kc=PC/P0
2. The working principle and characteristics of the heat sensitive dry reed relay
The thermal sensitive dry reed relay is a new type of thermal sensitive switch which uses the heat sensitive magnetic material to detect and control the temperature. It consists of a thermal magnetic, permanent magnetic ring, reed thermal installation piece, plastic substrate and other accessories. Thermal reed without coil excitation, the magnetic force generated by the permanent magnetic ring drive switch. The permanent magnetic ring to the dry spring could provide the magnetic force is determined by the characteristics of the temperature control temperature magnetic ring.
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3, solid state relay (SSR) working principle and characteristics
The solid state relay is a two terminal, and the other two terminals are the four end devices of the output terminal, and the isolation device is adopted to realize the electrical isolation of the input and output.
According to the type of load power supply can be divided into AC and DC type. According to the switch type can be divided into normally open and normally closed type. According to the isolation type can be divided into mixed type, transformer isolation type and photoelectric isolation type, with photoelectric isolation as the most.
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4, the working principle of the magnetic spring relay
Reed relay is the coil produces a magnetic field of magnetic reed actuation of the relay coil as a sensing device. Therefore, the characteristics of the magnetic reed relay, small size, light weight, fast response, short jump time and other characteristics.
An action, an opening or a closing circuit, when the whole ferromagnetic metal or other magnetic conducting material is close to it. By a permanent magnet and a dry reed pipe. A permanent magnet and a dry reed pipe is fixed on a frame without magnetic nor magnetic on. The permanent magnet polar line as the axis, the axis should be reed axis coincidence or coincidence. From far and near the adjustment of permanent magnet and dry reed pipe between the distance, when the dry reed pipe happened action (for normally open a dry reed pipe, closed; for the normally closed dry reed pipe, is off), the position of the magnet is fixed. At this time, when a piece of magnetic material, such as iron and near the magnet and a dry reed pipe, a dry reed pipe will happen again in action, return to the absence of an applied magnetic field; when the iron left, the dry reed pipe is opposite to the direction of movement. Reed relay structure strong contacts is sealed, high durability can as machinery and equipment of the position limit switch, can also be used to detect an iron door and the windows in the specified location.
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5, optical relay working principle
Optical relay for AC/DC and use the semiconductor relay, refers to light emitting devices and optical devices integrated devices. The input side and output side of the electrical insulation, but the signal can be transmitted through the optical signal.
The characteristic is that the life is semi permanent, the micro current drive signal, the high impedance insulation voltage withstand voltage, ultra small, light transmission, no contact... Etc..
Mainly used in measurement equipment, communication equipment, security equipment, medical equipment... Etc..