Which device provides overload protection by shutting off power during excessive current conditions?

An overload relay is specifically designed to provide overload protection in motor control circuits by monitoring the current flowing through the motor. When the current exceeds a predetermined threshold, indicating that the motor may be overburdened, the overload relay will open its contacts. This action interrupts the electrical supply to the motor, protecting it from damage caused by excessive heat that can result from prolonged overcurrent conditions.

Overload relays typically incorporate thermal elements or electronic sensing mechanisms that detect the heat generated by high current levels. This type of protection is crucial in motor applications to prevent the motor from burning out or sustaining other types of damage due to overheating.

While a circuit breaker does provide overload protection, its primary role is more about general current protection for entire circuits rather than specifically tailored for motor control where the overload relay is more focused on the motor's protection. Contactors and relays, on the other hand, are used to switch power to motor circuits but do not offer overload protection by themselves. They may work in conjunction with overload relays but do not serve the same protective function.