Modernizing a Refinery Brushless Motor Protection and Control System to Maximize Availability: A Case Study

This article presents the case study of a retrofit project that updated the excitation control system and motor protection on several brushless, synchronous motors at a major refinery in Texas, USA. Due to aging and failing components in the original excitation control system, the facility experienced recurring unexpected motor shutdowns. This article discusses the solution that was developed and implemented on these motors, which consisted of replacing outdated components in the exciter supply and control circuitry with simple, adjustable dc power supplies controlled by an updated protection and control relay. As a result of this retrofit, the motors continue to run ideally under automatic control, with significantly reduced system maintenance. The new design increased system reliability and decreased the likelihood of an unexpected shutdown due to an inadvertent component failure.