What is the function of an MG set?

An MG set, or motor-generator set, primarily serves to convert AC power into DC power. In the context of elevator systems, it is especially important for supplying the necessary DC power to a hoisting motor that operates the elevator. The MG set plays a crucial role in ensuring that the hoisting machinery receives a stable and efficient form of power, which is essential for the smooth functioning and control of the elevator's ascent and descent.

This set typically consists of an AC motor coupled with a DC generator. The AC motor runs on the building's supply voltage and produces the AC power, which the generator then transforms into the required DC power. This process provides the hoisting motor with the energy it needs, enabling precise control of elevator movements.

In contrast, other options focus on different functions or power needs. For instance, while hydraulic power is vital in certain elevator systems, it isn't the primary role of an MG set. Similarly, while MG sets generate power, their main application within an elevator context does not pertain to lights or managing elevator traffic, which are tasks performed by different systems within the elevator infrastructure.