What is NOT a function of a Thermal Overload Relay?

The function of a Thermal Overload Relay primarily focuses on protecting motors from prolonged overheating conditions due to overload situations. This relay works by using a bimetallic strip or thermistor that heats up as current flows through it, bending or triggering a switch when a certain temperature is reached, which indicates that the motor is overloaded for an extended period.

Detecting phase loss and monitoring phase unbalance are also critical functions that help in ensuring the motor runs efficiently and safely. By monitoring these conditions, the relay can provide feedback on the motor's operational status, which is essential for preventing damage due to imbalances or interruptions in power supply.

However, protecting against short circuits is not within the scope of a Thermal Overload Relay. Short circuits occur when there is a direct connection between the electrical paths with very low resistance, leading to a sudden surge of current that can bypass the relay's thermal sensing capabilities. Circuit breakers or fuses are specifically designed to handle short circuits by interrupting the current flow immediately, whereas a Thermal Overload Relay would not activate swiftly enough for this type of fault.

Therefore, the option that specifies the protection against short circuits is indeed the correct answer as it does not align with the functions of a Thermal Overload Relay.