Solutions for quality pre-control of crimp contacts used in electric power systems and electrical machines

Crimping is the most widely used method of pressure connection for permanent electrical contact between a wire conductor and a wire conductor terminating device. In this paper we present two solutions for connections quality pre-control of crimp contacts used in electric power systems and electrical machines and for early identification of the improperly executed connections, before final assembly. Thus can be avoid any damage that may occur during operation. The first solution supposes an experimental determination of specific losses by calculating the initial rate of temperature rise. This can be made drawing the tangent at the origin at heating curve. The method can be used to identify bad connections by passing a current through the winding at ambient temperature and simultaneously recording connections temperatures in the first few minutes since the current is setting. The second proposed solution is to apply to each element crimping an one level thermal indicator and making a test heating with a heating current corresponding to indicator critical temperature.