Motor cranking: Due to manufacturing and installation errors, the motor axis may tilt to varying degrees. Therefore, after the motor rotating part is assembled, the axis and the mirror plate level are initially adjusted. Under the condition that the force is relatively uniform, measure the guide bearing, flange, collector ring, etc. to check whether the inclination of the axis meets the requirements and make adjustments. The so-called turning refers to using manpower to turn the motor several times before starting the motor to determine whether the load driven by the motor (ie, the mechanical or transmission part) is stuck and the resistance increases, so as not to cause the motor to malfunction. The starting load increases and the motor is damaged (i.e. burned out). Therefore, it is generally necessary to crank the motor when starting the motor again after shutting down for one shift (8 hours). In a hydrogenerator, there are multiple large shafts connected between the rotor and the runner, so it is necessary to manually rotate the rotor for one revolution, usually through a thrust bearing, in order to determine the distance between the actual center and the theoretical center of the unit. The deviation will be adjusted based on the measured data. If the deviation is not adjusted, the deviation will be amplified by the axis extension and exceed the standard and affect the performance of the unit. It usually takes several turns to try to find the best center alignment.