ELECTRIC MOTORS

Problem Solving

Electric Motors

The following examples illustrate some of our contributions to this business sector:

• An electric motor manufacturer was suspicious of recently purchased silicon steel. Touchstone, whose engineers have been involved in the development and manufacture of such steels performed a chemical analysis of the steel and provided assistance in developing proper processing methods.
• A re-manufacturer of motors requested Touchstone to identify a copper alloy material used in the original manufacture of a motor. The analysis helped the manufacturer choose the proper material for the re-build.
• Touchstone was contacted concerning the failure of a drive shaft from an electric induction motor. Touchstone was asked to determine the cause of the failure and, if possible, to suggest a solution to the problem. TRL concluded that the breakage problem seen in this shaft resulted from lack of a proper radius at the location of diameter changes on the shaft where carrier bearings were located.
• A motor re-winding company requested that Touchstone perform an evaluation of a new electric motor winding system to determine whether claims of increased energy efficiency were valid. It was determined that under very specific circumstances this technology might provide marginal benefit, however, in general use, there was no benefit to the proposed design change.
• Touchstone performed failure analysis of an electric clay gun power lever arm which failed during service. The arm was to be manufactured from 4140 steel, cold-drawn and annealed with a target hardness of 200 Brinnel. Touchstone’s chemical analysis detected a high carbon content and a high sulfur content; Metallographic analysis revealed a very high pearlite content and high Brinell hardness. The fracture surface exhibited a brittle, transgranular fracture surface. All of these factors indicated use of the wrong material and/or heat treatment for the required application.

The above examples are only a sample of our work in this area. We would be pleased to provide any additional information you may require. We also invite you to review examples on our website of work that we have performed in support of other business sectors.