In our earlier post, we discussed about the basic introduction of Shock pulse tester. Now, In this post lets discuss about how to operate Shock pulse tester.
Various operations of SPT :
(A) SETTING RPM AND SHAFT DIAMETER:
Press the SPM/VIB key to select BEARING TEST. Now press set key for entering the rpm and diameter. Follow the following steps:-
(i) Press the set key again to move the cursor in first position in the RPM line.
(ii) Press UP and DOWN key to enter numeric value.
(iii) To shift the positions of cursor for entering the next number press both UP and DOWN key together, complete the rpm data.
(iv) Press SET key to move the cursor from rpm to diameter line. Follow the step (ii) and (iii) to enter the diameter value.
(v) Now press SET KEY to obtain the dBi value.
(vi) The instrument is ready to take normalized shock value reading.
(B) SHOCK PULSE READING:
(a) NORMALIZED READING :
(i) Program the Shock Pulse Tester by entering dBi value.
(ii) Now connect the SPT probe to the bearing casing as close as possible to the bearing.
(iii) Press key “M” for taking the reading.
(iv) Once dBm and dBc value is displayed, go for peak reading measurement.
(v) For peak reading measurement use up and down key to get peak indication flash.
(vi) Now continue using up/down key to get a possible delayed flash that indicate the peak shock available in the bearing, record this reading.
(vii) Observe the arrow indication pointing at which condition scale GOOD, CAUTION, BAD condition indicated by GREEN (0-20dBn), YELLOW (21-35dBn), RED (>35dBn) respectively.
(b) UNNORMALIZED READING:
(i) Need not program with dBi value.
(ii) Use the Shock Pulse Tester for measurement straightway without feeding rpm or diameter.
(iii) Reading observed in dBm or dBc will be absolute shock value dBsv.
(iv) There will be no arrow indication this time.
Note: dBsv-dBi=dBn i.e. reading measured in normalized scale (dBn) has less value by dBi amount when measured in unnormalized scale (dBsv ).
(C) PEAK READING:
- Once reading is taken in normalized or in unnormalized scale the spm go for peak reading
- Observe the display for dbm and dbc value
- Now press arrow key button up/ down, observe another dbm reading in bracket ().
- Come to a situation by using up/ down key when peak indication led start flashing.
- Try bring the flashing rate low, when led continuously glow; observe both dbm reading, they will be close enough.
- Take the dbm reading. Record this as actual maximum shock available in the bearing.
(D) TAKING TACHO READING:
- Use the tacho probe, connect it to tacho connector of the Shock Pulse Tester
- Now system automatically goes to tachogenarator function
- Press M key, led light beam is released , point it to a reflecting tape fixed on a rotational machine.
- Observe the rpm in the display.
- Before conducting the test, battery test is to be conducted first.
- The transducer is to be placed at nearest point on the bearing for taking exact reading.
I hope you have got some idea about how to operate Shock pulse tester.