Views: 16 Author: Site Editor Publish Time: 2022-08-16 Origin: Site
A relay is an electrical control device, which is a device that makes a predetermined step change in the controlled quantity in the electrical output circuit when the change of the input quantity (electricity, magnetism, sound, light, heat) reaches the specified requirements. electrical appliances.
Relays have a control system and a controlled system, and are usually used in automated control circuits, playing the roles of automatic adjustment, safety protection, and conversion circuits in the circuit.
There are many classification methods of relays, which can be based on principle of action, external dimensions, protection characteristics, contact load, product use, etc. Today, we mainly talk about classification according to the principle of action. You can follow us to learn more.
Under the action of the current in the input circuit, a relay that produces a predetermined response by the relative movement of the mechanical parts.
Includes DC electromagnetic relays, AC electromagnetic relays, magnetic latching relays, polarized relays, reed relays, and energy saving power relays.
(1) DC electromagnetic relay: the electromagnetic relay whose control current in the input circuit is DC.
(2) AC electromagnetic relay: an electromagnetic relay whose control current in the input circuit is AC.
(3) Magnetic Latching Relay: After the magnetic steel is introduced into the magnetic circuit, after the relay coil is de-energized, the armature of the relay can still remain in the state when the coil is energized, with two stable states.
(4) Polarized relay: a DC relay whose state changes depending on the polarity of the input excitation.
(5) Reed relay: a relay that uses the action of a reed sealed in the tube and has the dual functions of a contact reed and an armature magnetic circuit to open, close or switch circuits.
(6) Energy-saving power relay: The control current in the input circuit is an AC electromagnetic relay, but its current is large (generally 30-100A), small in size, and power-saving function.
A relay whose input and output functions are completed by electronic components without mechanical moving parts.
When the input signal is added or removed, the output part needs to delay or limit the time to close or open the relay of its controlled circuit until the specified time.
A relay that operates when the outside temperature reaches a specified value.
When the wind speed reaches a certain value, the controlled circuit will be turned on or off.
When the acceleration of the moving object reaches the specified value, the controlled circuit will be turned on or off.
Such as photo relays, acoustic relays, thermal relays, etc.