Any machine running with anti-friction bearings and gears will, several certain degree, exhibit high frequency rumbling. Rotary screw air compressors are an excellent of great for the of contraption. Single stage rotary screw compressors are along with two rotors that have anywhere from four in order to six lobes on each windmill. The rotors submit opposite directions with the lobes nearly touching to generate an a “screw” which compresses the air. The compressor usually driven by a motor directly coupled into the male rotor which consists of a gear to the coupling which in turn drives the appliance on the female rotor. The gears are timed such a fashion that the rotors never touch.
Given this mechanical configuration, vibration at a number of different high frequencies can or will occur:
Rotor Mesh Frequency — equals numerous of lobes of a man rotor multiplied by the running speed of the motor. Therefore, this frequency will be synchronous light and portable motor running speed.
Gear Mesh Frequency — equals variety of gear teeth multiplied by the running speed of the motor. Typically the case of multiple stage rotary screw compressor, just about be far more than one associated with gear mesh frequencies. This vibration additionally be synchronous with motor running stride.
Bearing Frequencies — which depend towards the particular bearing used in the machine. In general, the bearing frequencies will be non-synchronous with motor running speed. The interior and outer race frequencies will function ones most often seen.
Other Frequencies — which could be induced by resonances of machines or compressed air flow.
Standard alarming methods often do not work well on machines that naturally exhibit high frequency vibration, for rotary screw air compressors, even once they are running properly. Overall vibration levels are sometimes insensitive on the small alterations in vibration levels caused by bearing destruction. This is brought about by the good amount of vibration that is of course occurring in the industrial air compressor. Particular high frequency bearing detection tools or techniques end up being triggered with each measurement, once due to your vibration at a gears and rotors. Span of financial in “nuisance” alarms.
Given these problems in making use of the standard alarming techniques, is actually very common that compares spectral data on rotary screw air compressors. Spectral data normally compared for the previous measurements and to a reference multimeter. This can be a time-consuming and intimidating task, given many measurement points and the volume of of different frequencies can occur. One technique for speeding up this process is to evaluate the percentages of synchronous and non-synchronous vibration between measurements. Many vibration software programs calculate this data each and every spectrum. Bearing deterioration typically be non-synchronous vibration. Some other words, is actually possible to not a whole number multiple or harmonic of machine running ” cadence “.