Mains frequency
Due to historical developments, a mains frequency of 50 Hz is used in Europe, Asia, Australia, most of Africa and parts of South America, while a mains frequency of 60 Hz has become established for the public power grids in North America.The specification of the mains frequency is necessary for the selection of the electric drive. For pumps that are operated with single-phase or three-phase motors without a frequency converter, the synchronous motor speed changes in the same ratio as the frequencies, i.e. from 50 to 60 Hz by a factor of 1.2. In accordance with the affinity laws, this also changes the pump’s performance data.A frequency converter is often used to adapt the performance data to the operating point. The electrical energy drawn at the mains frequency is converted into a voltage with a different frequency in order to change the motor speed.
nsync = synchronous speed
f = frequency of the 3-phase power supply
p = number of pole pairs of the 3-phase motorKindly note that the above noted relation results in revs per second if the frequency unit is Hz.