Oil-break circuit breakers

Introduction. The problem of interrupting an electrical circuit which may be momentarily carrying millions of kilowatts is exceedingly difficult. The greater concentration of power at present under way and the obstacles to be overcome in controlling the huge electrical circuits of these developments are matters which were foreseen by the manufacturers, who keenly appreciative of the importance of these problems, are making earnest efforts to meet the conditions imposed. Unfortunately, it is inconvenient and at times even hazardous to make tests determining the ultimate rupturing capacity of heavy-duty oil circuit breakers, since these tests require the use of the largest power plants now in existence and those responsible for these power developments are rarely willing to loan their equipment for such tests. On account of the variable conditions of service reports obtained are of limited value and manufacturers are forced to accept incomplete information on the action of oil circuit breakers under operating conditions. This state of affairs is greatly improved where the engineers of the large power companies coöperate with the designers and carefully record and freely interchange data relating to all unusual disturbances.