A 100-kW, dc shunt generator, connected to a 220-V main, is belt-driven at 300 r/min, when the belt suddenly breaks and the machine continues to run as a motor, taking 10 kW from the mains. The armature winding resistance is 0.025 Ω, and the shunt field winding resistance is 60 Ω. Determine the speed at which the machine runs as a motor.