Light-load starting, in the starting process, the transmission equipment without load or with a slight load, starting load factor of μc = 0.1-0.5 starting torque coefficient μg of = 0.7; rotor starting current coefficient i2g = 1.25-1.6. The general start-up time of less than 20 seconds. Such as air compressors, pumps, and so on. 
 Light and heavy load starting: two cases, one is the transmission equipment in the starting process, the moment of resistance increase with speed down when starting the moment of resistance (μg = 0.5-0.8); starting torque μg of = 0.1; rotor starting current coefficient i2g = 1.6-2.0. The start time is greater than 20 seconds. For example, with the flywheel motor of the rolling mill drive. Another case is that the transmission equipment in the Chi move with the load or with a slight load, moment of resistance is smaller, the general body heavy, high-speed operation converted to motor shaft moment of inertia, the start time is often more than two seconds. The rheostat allows consecutive start several times, but starting the total time not more than 80 seconds for light loads. Heavy light-load or overload shall not exceed 120 seconds.