Development of Induction Motors for Emergency Protection Drives of Nuclear Power Plants

Possible design options of permanent magnet motors in the drive for moving the emergency protection rods of a nuclear reactor are compared, and the advantage of induction motors with electromagnetic excitation providing the greatest return on moment with a short-term current increase (forcing) is revealed. The design features of induction motors with electromagnetic excitation from the stator side for a short-term operating mode are considered. To prevent deep saturation of the magnetic circuit leading to an unproductive increase in the consumed power and additional heating, the design procedure proposes, first, to form the geometry of the stator magnetic circuit in the rotor position at which the phase flux linkage takes the maximum value and, then, to calculate the magnetization characteristic of the ferromagnetic sections of the magnetic circuit based on it. The choice of the working magnetic flux near the saturation section of this characteristic allows one to unambiguously determine the size of the rotor–stator gap, as well as its moment and energy characteristics. The method applies to induction motors with electromagnetic excitation, where it is required to repeatedly force the rotating electromagnetic moment due to a very short-term operating mode.