The innovation points of the invention are that stator core is designed as E shape, and one fault tolerant tooth is added to each stator core. Winding is enwound on armature tooth and permanent magnet on two sides of E shaped stator core. There is no winding on fault tolerant tooth. Windings on radial opposite two poles are connected in series to constitute one phase. Fault tolerant tooth insulates phase windings. Excitation magnetic field is produced by permanent magnet. Fault tolerant tooth provides magnetic loop for permanent magnet and armature winding. The invention makes circuit, magnetic circuit, and temperature field independent between phase to phase of motor. The fault tolerant motor possesses higher reliability, and capability of operation under fault. Reducing width of gullet can reduce pulsation of torsion. Magnet core can run at inflection point of magnetization curve. The motor is especially suitable to areas of high reliability of continuous operation.