What are equalizer rings used for?

Answer 1

An equalizer, or equalizer connection, connects two or more generators operating in parallel at a point where the armature and series-field leads join (see Fig. 7.13), thusconnecting the armatures in multiple and the series coils in multiple so that the load will

divide between the generators in proportion to their capacities. The arrangement of connections to a switchboard (Westinghouse Electric Corp.) is illustrated in Fig. 7.14.

Consider, for example, two overcompound-wound machines operating in parallel without

an equalizer. If for some reason there is a light increase in the speed of one machine, it will

take more than its share of load. The increased current flowing through its series field will

strengthen the magnetism, raise the voltage, and cause the machine to carry a still greater

amount until it carries the entire load. When equalizers are used, the current flowing through

each series coil is inversely proportional to the resistance of the series-coil circuit and is

independent of the load on any machine; consequently, an increase of voltage on one

machine builds up the voltage of the other at the same time, so that the first machine cannot

take all the load but will continue to share it in proper proportion with the other generators