What is the main purpose of Thermal Overload Relays?

The main purpose of Thermal Overload Relays is to provide protection against prolonged overload and phase issues. These relays are designed to monitor the temperature of an electric motor and disconnect it from the power supply if the temperature rises beyond a safe level due to excessive current draw. This typically happens when there is an overload condition, such as when the motor is working harder than it is rated for, which could lead to overheating and potential damage.

In addition to protecting against overloads, Thermal Overload Relays also address phase issues, which can occur when there is a failure in one phase of a three-phase system. Such failures can cause the motor to operate inefficiently and can lead to failure if the system is not monitored and protected appropriately. By using Thermal Overload Relays, operators ensure that their equipment has a safeguard against these potentially harmful situations, thereby extending the life of the motor and promoting safe operation.

The other options, while related to electrical systems, do not accurately describe the primary function of Thermal Overload Relays. These relays specifically focus on overload protection and phase monitoring rather than regulating voltage, enhancing current flow, or improving circuit efficiency.