When some of the generator output is used to supply the field current how is the generator described?

When a generator uses some of its own output to supply the field current, it is classified as self-exciting. This process occurs because the generator's output voltage is utilized to power the field windings, which in turn helps to generate the magnetic field needed for the generator to produce electrical energy. Over time, this configuration can lead to a build-up of voltage, making the generator capable of producing a stable output without the need for an external power source for the field current.

In contrast, separately excited generators derive their field current from an external source, meaning they do not rely on their own output voltage. Series excited generators have field windings that are connected in series with the load, which causes the field strength to vary with the load, while shunt excited generators apply a portion of the total output voltage across the field winding but do so using a different configuration than self-exciting. Understanding these distinctions is vital for anyone involved in the maintenance and installation of elevator systems, where generator behavior can influence overall system performance.