PLAN No. 1077. INSPECTION AND REPAIR
After electrical equipment has been assembled, it is inspected for defects before it is submitted to an electrical operation test such as is described below. Such inspection may comprise not only a checking of the dimensions and quality of the mechanical parts of the machine, but may also involve qualitative electrical tests. These are made to insure that there are no faults in the insulation, or misconnections in the windings. Frequently these inspection tests are applied before the component tested leaves the department in which it was made. Thus coils are tested to insure that they contain no short-circuits or crosses before they leave the winding department. Complete armatures are likewise subjected to an insulation test in the department where they are wound; a voltage considerably higher than that which will be imposed on the machine after it is in actual operation being connected to the armature temporarily by the tester. This high voltage is obtained from the secondary winding of a step-up transformer.
The mechanical inspection is made with micrometers, scales, gauges, and calipers in the same way as is the inspection of any machine-shop product. Checks for the proper connection of the coils in a machine can be made by standardized methods.