The correct method should take the shaft at one end as the base point. If conditions permit, you can install 2 dial indicators, divided into 4 points, that is, use the dial indicator several times every 90 to make the readings of each angle consistent.
It is the best centering method with high accuracy, which can be controlled within 0.02-0.10mm.The coupling finds the analysis of the offset situation. When installing a new pump, the verticality between the coupling end face and the axis can be omitted, but when installing the pump, you must check carefully and adjust if it is not vertical. Align after vertical.Under normal circumstances, you may encounter the following four
This situation.
 1）S1=S2，a1=a2 两半靠背轮端面是处于既平行又同心的正确位置，这
    The two axes must lie on a straight line. 
 2）S1=S2，a1 a2 两半靠背轮端面平行但轴线不同心，这时两轴线之间有
    Parallel radial displacement e=(a2-a1)/2. 
 3) S1 S2, a1=a2 Although the end faces of the two backrest halves are concentric but not parallel, there is an angular direction between the two axes
    Displacement.
 4) S1 S2, a1 a2 The end faces of the two backrest halves are not concentric or parallel, and there is a diameter between the two axes
The displacement e has an angular displacement.The first situation of the coupling is the state we are striving to achieve in the alignment.
The second, third, and fourth states are not correct, and we need to make adjustments to achieve the first situation.When installing equipment,
First install the driven machine (pump) so that its axis is in a horizontal position, and then install the master machine (micromotor), so
When aligning, only the active machine needs to be adjusted, that is, the method of adjusting the cushion surface under the feet of the active machine (micro-motor) is added to adjust.

 2. The measurement and adjustment method of the timing adjustment The following mainly introduces the two measurement adjustment methods commonly used in the maintenance process, according to the different measurement tools
It can be divided into: 
 1) Use a knife-shaped ruler and feeler gauge to measure the misalignment of the coupling and use a wedge-shaped clearance rail or feeler gauge to measure the non-parallelism of the end surface of the coupling. This method is suitable for elastic couplings with low speed and low precision requirements. equipment. 
 2) Use a dial indicator and a meter frame or a special aligning tool to measure the misalignment and non-parallelism of the two couplings. This method is suitable for rotating equipment with high speed, rigid connection and high precision requirements. 
 Note: 1) When using feeler gauges and knife-shaped gauges for alignment, the surface of the radial end face of the coupling should be flat, smooth, rust-free, and burr-free. 2) In order to see the light of the knife-shaped ruler, it is best to use a flashlight. 
         3) For the final measured value, the anchor bolts of the micro motor should be completely tightened without any looseness. 
         4) When aligning with a special tool, make the same mark. In order to avoid the increase of the measurement data error, the backrest wheel should be divided into 4-8 points in order to obtain accurate data. 
         5) Make a good record to make an important part of aligning.There are the following methods when adding and adjusting the cushion surface: 1) Straightforward (sensory) observation (experience adding and subtracting cushion) Because in the overhaul, the alignment of some pumps does not fully have good conditions and tools. When adjusting, the master’s Experience will play a big role. Every time you add or subtract pads, you should consider the tightness of the micro-motor bolts and the remaining amount). 2) Calculation method (1) Eliminate the height difference of the coupling first. The motor shaft should be lifted up with a gasket by h. This means that the front bearing A and the rear bearing B should be cushioned under the seat at the same time. (2) Eliminate the opening of the coupling. Add spacers of different thicknesses under the A and B bearings respectively. The spacers added on the B bearing should be a little bit behind the A bearing.The thickness of the total adjusting shim is: front support A: h+AC; rear support B: h+BD.Center deviation standard of water pump coupling (unit: mm) Rigidity and elasticity of speed 3000 0.02 0.04＜3000 0.04 0.06 ＜1500 0.06 0.08 ＜750 0.08 0.10 ＜500 0.10 0.15 The distance between the end face of the centrifugal pump coupling is large 8-12mm medium 6 8mm small 3-6mm