A new power factor and power factor tip-up measurement technique for stator bars and coils

Many contractual specifications for stator coils or bars prescribe maximum permissible levels on the values of power factor and power factor tip-up of the groundwall insulation. In addition, some utilities and large industrial users perform these measurements on new replacement coils or bars and utilize the resulting measurements to rank them prior to installation in the stator core. The actual procedures to be used for such measurements are not always specified, and, even when they are, the results maybe inaccurate and, consequently, misleading. This paper describes in detail a major source of error and presents a new technique which simplifies the measuring procedure and eliminates the source of error