Production testing of large D-C apparatus

ACCURATE ELECTRICAL TESTING for maintenance of quality control of d-c machines is highly desirable. To achieve this with the conventional load-run test methods necessitates that a good brush fit on the commutator be first established. Such fitting involves brush sanding, seating, and running under load until stability is obtained. This is a time-consuming and expensive process. The test here described offers a practical means of controlling the quality of the product in repetitive production. However, it neither obviates the necessity of load-testing in development work, nor of periodic load-testing as a check on quality in general production.