What is the working principle of an electromagnetic clutch?

[VonRosalie]

Electromagnetic clutch works by controlling the engagement and disengagement of the clutch through the energization and de-energization of the coil. It is a friction-type clutch where the clamping force is generated by electromagnetic force, enabling remote control with minimal control effort, making it suitable for automation. The function of the electromagnetic clutch is to transmit torque and power from the driving shaft to the driven shaft in various mechanisms, achieving rapid start, braking, forward/reverse rotation, or speed regulation. Utilizing the principle of electromagnetic induction and the friction between inner and outer friction plates, the electromagnetic clutch is an electromechanical connector that allows two rotating components in a mechanical transmission system to engage or disengage without stopping the driving component, serving as an automatically operated electrical device.

[McXavier]

I've been repairing cars for over 20 years, and electromagnetic clutches are commonly found in automotive air conditioning systems. Simply put, when you turn on the AC, the car's small computer sends a signal to the clutch. Electric current flows through the coil, generating a magnetic field that pulls the armature like a magnet. This armature is connected to the compressor shaft. Power is then transmitted from the engine belt to the compressor, initiating cooling or heating. When the AC is turned off, the current is cut, the magnetic field disappears, and a spring pushes the armature back to its original position, disconnecting the link and stopping the compressor. This design is incredibly smart—it saves fuel because the engine doesn't need to waste energy dragging an idle compressor. Regular checks are essential: watch out for burnt-out coils or stuck armatures, as these can prevent the AC from turning on or cause excessive engine noise. Also, inspect the plugs frequently; aging wiring can lead to malfunctions. Don’t wait until summer when you're sweating in the car to discover the problem!