|Measurement procedures and operational conditions
||Frequency range 10 Hz to 1000 Hz, ( ISO 2954, 10816-1)
Speed <600 rpm frequency range <2Hz
measuring system is not influenced by environmental factors such as:
- temperature variations;
- magnetic fields;
- sound fields:
- power source variations;
- transducer cable length;
- transducer orientation,
- Exposed parts which are accessible,
- Measurements Should not include the local resonance or amplifications
- provide adequate sensitivity to the machine dynamic forces.
- this will require two orthogonal radial measurement locations on each bearing cap or pedestal, as shown in figures 1 and 2.
- Vertical and horizontal directions are usually preferred for horizontally mounted machines.
- vertical or inclined machines usually in the direction of the elastic axis is used
|Continuous and non-continuous monitoring
- Large equipments continuous monitoring can be done
- Smaller and hand held devices periodic monitoring and trend analysis can be done with greater reliability
- Measurements shall be taken when the main bearing is running in their normal steady state operating conditions
- For varied speeds/Loads, measurements will be taken for all the variations and maximum will be considered
- If the measured vibration is greater than the acceptance criteria then the measurements to be taken with the machine off.
- If the vibrations measure in point 3 exceeds 25% of the measured vibrations ( when machine on) then corrective action may be necessary to reduce the effect of background vibration.