A Motor Overload Relay (MOR) is an electrical component that monitors the current flowing through an electric motor. Its primary purpose is to protect the motor from damage due to excessive load or prolonged operation beyond its rated capacity. When a motor is overloaded, it can overheat, leading to insulation breakdown, motor winding damage, or even motor failure. The overload relay detects these conditions and disconnects the power supply to the motor, thereby preventing permanent damage.

    Overload relays are typically used in conjunction with motor starters and contactors. They are available in different forms, including thermal overload relays, electronic overload relays, and solid-state overload relays. Each type works on slightly different principles, but the core function remains the same： protecting the motor from overcurrent conditions.