Читать книгу Handbook of Large Hydro Generators - Geoff Klempner - Страница 34

The electric machine can be specifically designed to operate as a pump motor so it performs useful physical work. In this particular arrangement, the motor pumps water through the penstock for irrigation or as storage when power is abundant to be used later to generate when power is in short supply. Synchronous pump motors are designed to operate at a fixed speed without any slip between the armature frequency and the fields rotating frequency. To bring the motor to synchronous speed, it must be accelerated by a method consistent with its design. A separate induction starting motor dedicated to accelerating the synchronous rotor is a common starting method. Other methods incorporating variable frequency sources or across‐the‐line inductive starting by the rotor damper windings are also used. In the situation, where across‐the‐line starting is used, the damper windings will get very hot quickly and the machine must be synchronized within the recommended time by the manufacturer. Failed synchronization attempts must allow for cooling of the damper circuit before an attempt to start the machine is made again. This cooling off period will also be specified by the manufacturer. Failure to follow these set procedures can result in overheated and even melted damper assemblies which in turn will affect starting performance and may require repair depending on the severity. If a known excursion from these procedures has occurred, it is highly recommended that a visual inspection of the damper assembly by a knowledgeable person be performed.