An overload relay is a device that offers protection to electrical motors against overcurrent or motor overload conditions. It works by monitoring the electric current that passes through the motor and shuts down the motor if it exceeds the safe limit. 

The great advantage of using an overload relay is that it helps to prevent potential damage to the motor, thus prolonging its lifespan and avoiding costly repairs or even replacement. 

Moreover, it provides an added level of safety to the motor system, preventing motors from overheating, short-circuiting, or even causing a fire, thus significantly reducing the risk of danger to personnel and property. 

Hence, the use of overload relays is highly recommended in industrial and commercial applications, where the reliability and safety of electrical equipment are crucial for maintaining productivity and efficiency.