There are many classification methods for relays, which can be classified according to the principle of action, external dimensions, protection characteristics, contact load, and product use.
First, according to the principle of action
1. Electromagnetic relay
A relay that produces a predetermined response by the relative motion of mechanical components under the action of current in the input circuit.
It includes DC electromagnetic relay, AC electromagnetic relay, magnetic holding relay, polarization relay, reed relay, energy-saving power relay.
(1) DC electromagnetic relay: The electromagnetic relay in which the control current in the input circuit is DC.
(2) AC electromagnetic relay: The electromagnetic current relay whose control current in the input circuit is AC.
(3) Magnetic holding relay: The magnetic steel is introduced into the magnetic circuit. After the relay coil is de-energized, the armature of the relay can still maintain the state when the coil is energized, and has two stable states.
(4) Polarized relay: A DC relay whose state changes depending on the polarity of the input excitation amount.
(5) Reed relay: A relay that opens, closes, or switches a line by a action of a reed that is sealed in the tube and has a dual function of a contact reed and an armature magnetic circuit.
(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.
2. Solid state relay
A relay that performs input and output functions by electronic components without mechanical moving parts.
3. Time relay
When the input signal is added or removed, the output portion needs to be delayed or time-limited until the specified time to close or open the relay of its controlled line. 4. Temperature relay
A relay that acts when the outside temperature reaches a specified value.
5. Wind speed relay
When the speed of the wind reaches a certain value, the controlled circuit will be turned on or off.
6. Acceleration relay
When the acceleration of the moving object reaches the specified value, the controlled circuit will be turned on or off.
7. Other types of relays
Such as optical relays, acoustic relays, thermal relays, etc.
Second, according to the size of the size
The relay with the longest side dimension of the micro relay is no more than 10mm
Ultra-small relays with a longest side dimension greater than 10mm but no greater than 25mm
Small relays with a longest side dimension greater than 25mm but not greater than 50mm
Third, according to the contact load
The micro power relay is less than 0.2A relay.
Relay of weak power relay 0.2~2A.
Relay of medium power relay 2~10A.
High power relay 10A or more relay.
Relay for energy-saving power relay 20A-100A
Fourth, according to the characteristics of protection
The sealed relay is welded or otherwise sealed to seal contacts and coils in the metal cover, and the relay with low leakage rate
The plastic-sealed relay adopts a sealing method to seal contacts and coils in a plastic cover, and a relay with a high leakage rate.
A relay for protecting a dust cover relay cover by closing contacts and coils
Open relays do not use protective covers to protect relays such as contacts and coils
5. According to the purpose
Communication relays (including high-frequency relays) These types of relay contacts have a load range from low to medium current, and environmental conditions are not required.
Relays used in machine tool relays have large contact load power and long life.
Relays used in relay household appliances for home appliances require good safety performance.
Relays used in automotive relay vehicles, which have high load switching power and high impact and vibration resistance.