Oscillations in operation, after the conditions, the two should first be broken off the shaft, the analysis of the peak from the pump is still a motor, and carefully carefully column motor base and centrifugal pump docking screw is not tightened, the flatness after assembly is not the deviation.
1. Motor oscillation source and identification
(1) The working speed ratio of the motor rotor is close to the critical speed. By calculating whether the torsional stiffness of the motor shaft and the operating frequency of the motor torsional vibration are close to the critical speed of the motor, the pump Angle frequency and the power grid frequency, the coshock can be caused. In particular, when the motor is used, the oscillation problem needs to be analyzed and calculated. The operating speed ratio of the motor rotor should be less than 25% of the critical speed or higher than 40% of the critical speed. In the analysis, it is also necessary to consider that the quality of the motor rotor can not be simplified into a concentrated quality situation, but is spread along the drive shaft, so the critical speed analysis should be analyzed to the second and third order critical speed.
(2) Instability of high temperature long axis motor rotor.
The instability of the high temperature long axis motor rotor is a key and more common oscillation reason, such as: 17#, 19# motor, using the rate vibrometer (displacement meter) to measure the motor oscillation rate of 9.8-l0mm/s, compared with IS02372 oscillation rate specification, Class III mechanical equipment should be less than 4.5mm/s, but in the case of 9.8-l0mm/s, using the vibrometer to measure the motor amplitude value reached 0.30mm. In order to understand the instability level of the high-temperature long-axis motor rotor, we designed two steel frame structures to separate and build two parallel rails (it is necessary to pay attention to the steel frame structure should have sufficient bending stiffness), the surface of the rail is treated into a wetting face, and the level of the rail surface is adjusted and fixed with the level of each other. During the inspection, the motor rotor is placed above two rails, and the high-temperature long-axis motor rotor is turned round and back several times. After each time, it is marked on the bottom of the motor rotor. Stick the adhesive on the symmetry point of the orientation, and then turn the rotor several times until the motor rotor can be terminated in any direction, and it is recognized that the high-temperature long-axis motor rotor has reached the balance. The equivalent circuit quality replaces the adhesive to complete the motor rotor balancing work. If the above method is still unable to deal with the problem, it is necessary to make the motor rotor dynamic balance check. After the above two motors add 45-5g balance weight on the side of the motor rotor, the amplitude value is reduced to 0.05mm, and the oscillation rate value is measured by the displacement meter at about 2.1mm/s.
(3) For the motor that has been started normally for a period of time, the oscillation reason to check the rolling bearing clearance is not too large, the drive shaft seat fixed screw is not loose, the drive shaft is damaged and bent or a part of the winding short-circuit fault, the magnetic density is uneven, the annular gap between the rotor and the stator generally can not exceed 10%.
It is particularly noteworthy that when the motor amplitude value is close to the index value, that is, it is still within the qualified range, and the motor amplitude value will usually exceed the standard after the load, mainly because all the factors of the oscillation of the deep well pump transmission device are the results of interaction and joint action.
