Vibration Fault Analysis of Large-scale Long-axis Deep Well Pump (2)

Motor rotor imbalance is the most important and common causes of vibration, such as: 17 #, 19 # motor, the speed vibration meter (displacement meter) measured motor vibration speed 9.8-l0mm / s, control IS02372 vibration speed standard, Class III machinery should be less than 4.5mm / s, while in the 9.8-l0mm / s state, measured with a vibrometer amplitude of the motor reaches 0.30mm. In order to find out the unbalance degree of the rotor of the motor, we made two steel frames on the scene to set up two parallel rails (pay attention to the steel frame should have sufficient rigidity), the surface of the rails processed into smooth and clean, Face adjustment and fixed. Check the motor rotor placed on top of the two rails, manually push the rotor to scroll back and forth several times, to be stationary after each, under the rotor marked. With sticky paste in the emphasis position of the symmetry point, and then rotate the rotor several times until the rotor can stop at random position, make sure the motor rotor has reached a state of static equilibrium. To replace the paste with equivalent quality to complete the balance of the motor rotor. If using the above method still can not solve the problem, you need to motor balancing test motor. The above two motors that increase 45-5g balance weight on the rotor side, the amplitude value reduced to 0.05mm, with the displacement meter measured vibration velocity value of 2.1mm / s or so. (3) The motor that has been used normally for a period of time should check whether the bearing clearance is too large, whether the fixing screws of the shaft base are loose, whether the shaft is worn and bent or a part of the windings is short-circuited, and the air gap is not uniform. Stator ring gap between the general shall not exceed 10%. Of particular note is that the motor close to the standard value when the amplitude value, i.e., the case that the still acceptable range after the motor-load amplitude value will often exceeded, because the entire deep well pump drive system vibration factors affect each And work together to result. 2. Pump body vibration and judge (1) pump installation and assembly caused by vibration. After the installation of the pump body and the thrust level and vertical pipe overtemperature will cause the pump body vibration, while the three control values ​​have some relevance. After the pump body is installed, the total length of the pumping pipe and the pump head (excluding the filter) is 26m, all of which are suspended. If the vertical deviation of the pumping pipe is too large, the pump and the shaft will cause violent vibration . Yang pipe vertical tolerance is too large will be in the pump during the operation of alternating stress, causing Yang pipe fracture. Deep well pump assembly is completed, Yang pipe in the total length of the vertical error should be controlled at ± 2mm. Pump horizontal and vertical horizontal error <0.05 / l000mm. The pump head impeller static balance of tolerance is not more than 10g, after assembly should be 8-12mm up and down the string moving clearance. Installation and assembly gap error is caused by the pump vibration is an important reason. (2) drive shaft whirl. Whirl, also known as "rejection turn", is a self-excited vibration occurring on the rotating shaft. It has neither the characteristics of free vibration nor the type of forced vibration. It is characterized by the axis of the shaft in the bearing performance of the rotation, this vibration does not occur when the shaft reaches the critical speed, but in a larger range and the rotation speed of the shaft itself less. Deep well pump rejection mainly caused by inadequate lubrication of the bearing lubrication, if the shaft and bearing clearance between the larger, then the direction of rotation and the axis of rotation in the opposite direction, this situation, also known as shaft jitter. In particular, deep well pump shaft is very long, rubber bearings and shaft with the gap 0.20-0. 30mm, when the shaft and the bearing there is a certain gap, the shaft and the bearing is not the heart, the center distance is large, the gap and the lack of lubrication, for example Deep well pump rubber bearing lubrication Supply pipe rupture, blockage, misoperation caused by inadequate or inadequate water supply and other circumstances, the more prone to jitter. In a moment of rotation of the journal and rubber bearings in contact at one point, the journal by the bearing to its tangential force, the role of the direction of force and shaft speed in the opposite direction, the force to the axis of translation, the mechanical effect Equivalent to a counterclockwise torque and a force acting on the journal center parallel to the tangential direction of the contact point of the bearing wall and tends to move the journal downwards so that the journal will be pure along the bearing wall Rolling, equivalent to an internal gear, so that the formation of the axis of rotation in the opposite direction of rotation.