This paper investigates the effects of single-phase short-circuit faults (SCF) on the electromagnetic (EM) force and vibration compared with the normal condition of the motor. Firstly, this paper introduces the structure of the modular motor. Secondly, optimize the modular motor structure to suppress the short-circuit current and ensure that the motor can run under the fault. Finally, the magnetomotive force (MMF) compensation fault-tolerant strategy is introduced, and based on the Maxwell stress tensor method, the theoretical analysis results of the radial force under the fault and magnetomotive force compensation are presented and FEA results are given to verify the theoretical analysis.