Synchronous versus induction motors: plant efficiency benefits resulting from the use of synchronous motors

Induction motors are often the choice for various industrial production processes. Use of an induction motor, however, will result in increased lagging power-factor burdens in the plant. This burden often must be corrected by adding capacitors. If not, the result is the penalty of larger kilovoltampere burdens to the interconnected system. The synchronous machine, with the aid of an intelligent excitation controller, can control power factor to reduce the plant reactive loading to the connected system. This article discusses the application of the synchronous motor at the Lion Oil refinery and the digital excitation system used to control the machine power factor.