Classification of Relays

There are various methods to classify relays, including based on operating principles, physical dimensions, protection characteristics, contact load, and product applications.

1. Classification based on operating principles:

1. Electromagnetic Relays: Relays that generate a predetermined response through relative movement of mechanical components under the influence of current in the input circuit. This category includes DC electromagnetic relays, AC electromagnetic relays, latching relays, polarized relays, reed relays, and energy-saving power relays.

• DC Electromagnetic Relays: Electromagnetic relays with control current in the input circuit being DC.
• AC Electromagnetic Relays: Electromagnetic relays with control current in the input circuit being AC.
• Latching Relays: Relays that utilize magnetic poles in the magnetic circuit to maintain their state after the coil is de-energized, possessing two stable states.
• Polarized Relays: DC relays where the change in state depends on the polarity of the input excitation.
• Reed Relays: Relays that use a sealed enclosure, with the action of a reed switch and the armature magnetic circuit serving a dual role to open, close, or switch circuits.
• Energy-saving Power Relays: AC electromagnetic relays with control current in the input circuit being AC, but with high current (typically 30-100A), small size, and energy-saving capabilities.

2. Solid State Relays: Relays that have input and output functions accomplished by electronic components without mechanical moving parts.
3. Time Relays: Relays that require a delay or time limit for the output part to close or open the controlled circuit when the input signal is applied or removed for a specified time.
4. Temperature Relays: Relays that actuate when the external temperature reaches the specified value.
5. Wind Speed Relays: Relays that connect or disconnect the controlled circuit when the speed of wind reaches a certain value.
6. Acceleration Relays: Relays that connect or disconnect the controlled circuit when the acceleration of a moving object reaches a specified value.
7. Other types of Relays: Examples include photoelectric relays, sound relays, thermal relays, etc.