(1) power direction relay
When the input quantity (such as voltage, current, temperature, etc.) reaches a specified value, the output circuit to be controlled by the conductor or disconnect the electrical appliances. Can be divided into electrical quantity (such as current, voltage, frequency, power, etc.) relay and non-electrical quantity (such as temperature, pressure, speed, etc.) relay two categories. It has the advantages of fast action, stable work, long service life, small size and so on. Widely used in electric power protection, automation, motion, remote control, measurement and communication devices. [1]
(2) electromagnetic relay
Electromagnetic relay is generally composed of iron core, coil, armature, contact reed, etc.. As long as the coil ends plus a certain voltage, the coil will flow through a certain current, thus generating an electromagnetic effect, the armature will be attracted in the electromagnetic force under the action of overcoming the return spring tension suction to the iron core, which drives the armature's moving contacts and static contacts (normally open contacts) suction. When the coil is powered off, the electromagnetic suction also disappears, the armature will return to its original position under the reaction force of the spring, so that the movable contact and the original static contact (normally closed contact) release. This suction, release, so as to achieve the purpose of conduction in the circuit, cut off. For the relay "normally open, normally closed" contacts, can be distinguished in this way: the relay coil is not energized in the disconnected state of the static contacts, known as "normally open contacts"; in the on state of the static contacts known as "normally closed contacts The static contact in the on state is called "normally closed contact". Relays generally have two circuits, for low-voltage control circuits and high-voltage operating circuits.
(3) solid state relay (SSR)
Solid state relay is a two terminals for the input, the other two terminals for the output of the four-terminal device, the middle of the use of isolation devices to achieve electrical isolation of the input and output.
Solid state relays can be divided into AC and DC types according to the type of load power. According to the switch type can be divided into normally open and normally closed type. According to the isolation type can be divided into hybrid, transformer isolation type and photoelectric isolation type, photoelectric isolation type for the most.
Solid state relay dedicated solid state relay can have a short-circuit protection, overload protection and overheating protection, and the combination of logic curing package can realize the user needs the intelligent module, directly used in the control system. Solid state relays are now widely used in computer peripheral interface devices, thermostat systems, temperature regulation, furnace heating control, motor control, CNC machinery, remote control systems, industrial automation devices; signal lamps, dimming, blinker, lighting stage lighting control system; instrumentation, medical equipment, photocopiers, automatic washing machines; automatic fire protection, security systems, as well as as the power factor compensation of the grid power capacitor In addition, it is widely used in chemical industry, coal mine, etc. for explosion-proof, moisture-proof and corrosion-proof occasions.
(4) Thermal reed relay
Thermal reed relay is a new type of thermal switch that utilizes thermal magnetic material to detect and control temperature. It consists of a temperature-sensitive magnetic ring, constant magnetic ring, reed switch, thermally conductive mounting plate, plastic backing and some other accessories. The thermal reed relay does not use coil excitation, but the magnetic force generated by the constant magnetic ring to drive the switch action. The ability of the constant magnetic ring to provide magnetic force to the reed switch is determined by the temperature control characteristics of the temperature-sensitive magnetic ring.
(5) Reed Relay
The reed relay is a coil that generates a magnetic field to actuate the reed switch, which is a coil sensing device. Therefore, reed relays are characterized by small size, light weight, fast response time, and short beat time.
When a piece of ferromagnetic metal or other magnetically conductive material and its proximity, the action occurs, open or close the circuit. Composed of permanent magnets and reed switches. Permanent magnet, reed switch is fixed in a non-conductive and non-magnetic bracket. The axis of the north and south poles of the permanent magnet should coincide or almost coincide with the axis of the reed switch. Adjust the distance between the permanent magnet and the reed switch from far to near, and fix the position of the magnet when the reed switch just happens to be actuated (for a normally open reed switch, it becomes closed; for a normally closed reed switch, it becomes disconnected). At this time, when there is a whole piece of magnetic material, such as iron plate close to the magnet and the reed switch at the same time, the reed switch will once again be actuated, restored to the state when there is no magnetic field; when the iron plate leaves, the reed switch that is the opposite direction of action. Reed relays have a sturdy structure, sealed contacts and high durability, and can be used as position limiting switches for mechanical equipment, or for detecting whether an iron door, window, etc. is in a specified position.
(6) optical relay
Optical relay for AC / DC and semiconductor relays, refers to the light-emitting device and light-emitting device integrated device. The input and output sides are electrically insulated, but the signal can be transmitted by optical signals.
It is characterized by semi-permanent life, small current drive signal, high impedance insulation withstand voltage, ultra-compact, optical transmission, no contact...etc..
Mainly used in measurement equipment, communication equipment, security equipment, medical equipment...etc..
(7) Time Relay
Time relay is a kind of control appliance that uses electromagnetic principle or mechanical principle to realize time-delay control. It has many types, including air-damped, electric and electronic types.
The air-damped time relay is often used in AC circuits, which utilizes the principle of air throttling through small holes to obtain the delay action. It consists of three parts: electromagnetic system, time-delay mechanism and contacts.