Only by accurately identifying the noise source of the hydraulic oil pump motor can we take appropriate measures to solve the problem symptomatically. The editor of Dalan Motor combined with the actual work to introduce a few methods to identify the main noise sources, to share with you!
1. Motor noise identification method:
(1) Power-off method
Using the characteristics of electromagnetic noise that varies with the strength of the magnetic field, the size of the current, and the level of conversion, the motor that is running at no load is suddenly powered off. If the noise disappears immediately, this is electromagnetic noise; if the motor continues to run by inertia after the power is turned off, no obvious noise The improvement is mechanical noise.
(2) Change voltage method
When the power supply voltage is rapidly reduced to a certain limit (but there is no major change in the control speed), if the electromagnetic noise changes significantly with the voltage, the other noise is basically unchanged.
Current test method
If the stator winding is asymmetrical or the internal phase failure, inter-turn and other faults, the three-phase current is unbalanced; if the rotor breaks the bar or the wound rotor three-phase asymmetry, then the stator current fluctuates, it can be determined as electromagnetic noise.
(3) Drag method
Use a low-noise motor to drive the tested motor to rotate. If it is a wound rotor motor, you can use the method of lifting and lowering the carbon brush to eliminate the carbon brush noise factor.
(4) Dismantling parts method
The aerodynamic noise has stable characteristics, which can be identified by removing the noise before and after the fan (small motor) or external blower (large and medium motor). In addition, by replacing fans with different outer diameters and types, the difference in noise can be distinguished at different speeds, and fan noise can also be identified.
Second, the reason for the abnormal sound of the motor operation
(1) When the stator rubs against the rotor, there will be a harsh "click" sound, which is caused by the bearing failure.
(2) The motor runs without phase, and the roar is particularly loud.
(3) When the bearing is severely deficient in oil, the sound of "bone lu" can be heard from the bearing chamber.
(4) The wind blade hits the shell or there is debris, and makes an impact sound.
(5) When the cage rotor guide bar is broken or the winding rotor winding joint is disconnected, sometimes the high and low "buzzing" sound, the speed becomes slower, and the current increases.
(6) The wiring at the first end of the stator winding is wrong, there is a low roar, and the speed drops.
(7) The stator slot wedge is loose or broken, and the sound of "sizzle" can be heard.
----- Responsible Editor: Dalan Oil Pump Motor 02-Procurement Consultant
Copyright http: / (Dalan Motor) Reprint, please indicate the source
================================================== ================================================== ======
