Regulation of A-G generators with suddenly applied loads

THE determination of the voltage regulation of a-c generators with suddenly applied load has become a problem of considerable importance. When the load which may be added suddenly is appreciable compared with the connected generating capacity, consideration must be given to the effect of the voltage drop on other connected load as well as on that just added. Too great a drop may result in the dropping out of a-c contactors on other equipment, stalling of heavily loaded motors, malfunctioning of radar or other voltage-sensitive equipment, and in adverse effects upon the starting characteristics of motors thrown on the line. Relatively small power plants with large motor loads are particularly subject to this phenomenon since the starting load may be several times the running load. Examples are isolated coast-defense gun installations, naval ship-service generators, industrial power plants, and auxiliary house generators of central-stations. In the latter case a heavy motor load may be transferred to the house generator if the normal supply fails.