If the measurement is made on the motor lead, the internal coil is damaged. If no trace of burning is found, it is mostly because of the thermal fuse of the coil. You can carefully unscrew the four screws of the motor, find a white thermal fuse and fix it on the surface of the coil, and measure whether it is open. If it is broken, find a replacement with the same specification. If there are no replacement parts, the emergency solution is to connect the two wires. But when in use, keep the electric fan away from flammable materials to prevent the fan from overheating and catching fire.