Pulse Testing Laboratory for Interrupting Device Development

The development of circuit interrupting devices can be accomplished more efficiently if not delayed by problems which are related to the laboratory in which tests are made. A unique current pulse laboratory has been created which simplifies the connection of test samples to the source of power. The control and timing of switching devices has been automated to reduce the time required for adjustment and to improve reliability in the operation of protective devices. Special ultra-high speed switches have been designed which are used for synchronized closing on a selected point-on-wave and for short circuiting the test device at the end of a current loop. The ability to protect the test sample by short circuiting provides information on conditions existing at the instant of failure of a device, since the test can be terminated before any extensive damage to the devices has occurred. Furthermore, the cooperative use of two ultra-high speed closing switches makes possible the injection into a test device of precisely controlled energy pulses in the form of loops of current from a power frequency source. This paper describes the equipment required to perform controlled pulse tests and discusses the advantages which result.