Optimal Characteristics of a Variable-Frequency Centrifugal Pump Motor Drive

Efficient variable-frequency control of the centrifugal pump drive motor is preferable to fluid control by a throttling valve or a bypass valve in many applications. The properties of the centrifugal pump as a motor load are discussed and the implications for the drive design. Also discussed are other properties of the motor drive in a pumping system such as startup behavior, response to pump overload, and loss of priming fluid as well as its characteristics as a control system element. Since fans and centrifugal blowers are similar in operation to centrifugal pumps, much of this discussion is also applicable to them. The aim is to give the specifier of pumping system components a set of criteria with which to judge the suitability of a given motor drive algorithm for his pumping application.