Which statement regarding synchronous motors is false?

Synchronous motors are unique in their operation compared to other types of motors, particularly their ability to maintain synchronous speed with the supply frequency. One key characteristic of synchronous motors is their ability to operate at both lagging and leading power factors. When powered, they can exhibit different power factor behaviors depending on their excitation levels.

The statement regarding the motor's power factor regulation is false. Synchronous motors can indeed regulate the power factor by adjusting their excitation. If operating under-excited, they can operate at a lagging power factor, drawing reactive power from the grid. Conversely, when over-excited, they can provide reactive power to the grid, allowing them to operate at a leading power factor.

Additionally, synchronous motors can run at synchronous speed, matching the power system’s frequency. This synchronization allows for precise speed control without slip, making them valuable in certain applications. Therefore, the ability to regulate the power factor while being synchronized to the line frequency is a critical advantage of synchronous motors, affirming why the statement claiming they cannot regulate power factor is inaccurate.