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The so-called \"cranking\" refers to the act of turning the pump a few times by hand or using a cranking device before starting the motor. This is done to determine whether there is any sticking or increased resistance in the load driven by the motor (i.e., the mechanical or transmission components), thereby preventing the motor from being overloaded during startup and damaged (i.e., burned out). Therefore, when starting up the equipment again after it has been shut down, it is necessary to turn the shaft of the machine. Purpose of turning the shaft: (1) Purpose of turning the shaft of a pump before starting it up: 1. Whether it is a newly installed pump or one that has just been overhauled, turning its shaft helps to determine whether it operates smoothly, without any jamming, and whether there are any unusual noises inside; this prevents damage to the pump during startup or damage to the motor due to excessive current. 2. Some large-scale units are also used for warming up and lubrication before startup, in order to prevent localized overheating of the rotor and the casing after startup, which could lead to thermal deformation. (2) Purpose of turning the pump shaft when it is shut down: 1. For a unit that has just been stopped (in the case of a normal shutdown), this is to prevent thermal deformation. Generally, it needs to be cooled for a short while before being coiled. 2. For units that have been out of service for an extended period, it is necessary to rotate the shaft regularly to prevent bending or deformation of the shaft, as well as to avoid jamming of the pump rotor due to the transfer of media with high viscosity; generally, the shaft should be rotated 540 degrees each time. II. Pump turning-over system: 1. The user unit shall, based on the actual condition of each pump, establish a specific turning-over schedule (per shift, per day, or per week) for them. 2. For pumps equipped with interlocked auto-start functions, cranking operations must be carried out while ensuring production and personal safety. 3. The cranking operation must cover at least one and a half turns each time. Clear turning marks should be marked on the exposed parts that rotate with the equipment (such as shaft ends, couplings, etc.), and these marks should correspond to the turning cycle. 4. It is necessary to maintain records of pump cranking; after each cranking operation, details such as the identifier and name of the cranking equipment, the cranking mark, the cranking time, and the person who performed the cranking should be recorded. III. Steps for turning the pump motor shaft: 1. Electric shaft turning: The worm and worm gear as well as the gear reduction mechanism of the shaft turning device convert the rotation generated by the shaft turning motor into rotation of the crankshaft, thereby enabling the shaft to be turned. Before starting the machine, it is necessary to turn the shaft in order to push the small piston to its extreme rear position. To unlock the shaft turning handle, it must be pulled outward from the shaft turning cover and then adjusted to the shaft turning position; at this point, the rotation of the shaft turning handle causes the pinion to slide axially inward to its extreme position, allowing it to engage with the gear. Once the shaft turning motor is started, shaft turning can be carried out ； At this time, since the pressure oil acting on the pressure regulation controller is connected to the drain port of the handle box, it ensures that the contacts of the pressure regulation controller open, preventing the main motor from starting. The crank device can rotate the shaft in both forward and reverse directions; this can be achieved by moving the control lever to the corresponding crank position. It must be noted that whether it is for cranking or running the machine, the oil pump motor must be started first. 2. Manual turning of the shaft: ① Turning the shaft before starting the equipment: Use an F-type shaft-turning wrench to turn the shaft at the coupling location of the equipment; generally, it should be turned at least one and a half turns before the equipment can be started. ②Regular turning of standby equipment: Since some equipment transports media with high viscosity or containing dust, this can cause sticking and blockages in the equipment’s rotors; therefore, it is necessary to turn them regularly. Of course, for equipment that is parked for long periods of time, especially those with relatively long shafts, it is necessary to perform regular shaft turning to prevent the shaft from bending; the number of degrees turned in each rotation should be an odd multiple of 180 degrees in order to correct any bending of the shaft. IV. Safety precautions when turning the pump shaft by hand: To ensure the safety of the equipment and the personnel performing this task, it is necessary to assign specific individuals to carry out this work under unified command, in order to prevent injuries to hands, feet, etc. caused by the inertia of the equipment. A dedicated person must supervise the start button while the machine is being turned. After turning the machine, this person should instruct everyone to stay away from the equipment, and only then return to the start button to press it personally in order to start the machine. No other person shall arbitrarily command the activation of the equipment. The so-called \"cranking\" refers to the act of turning the pump a few times by hand or using a cranking device before starting the motor. This is done to determine whether there is any sticking or increased resistance in the load driven by the motor (i.e., the mechanical or transmission components), thereby preventing the motor from being overloaded during startup and damaged (i.e., burned out). Therefore, generally, when restarting the equipment after it has been shut down, it is necessary to turn the shaft.