SPM leonova emerald, User Manual

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D
D:14
Shock pulse measurement
The absolute shock pulse level of a bearing, measured in dBsv (decibel shock value), is both a function
of rolling velocity and of bearing condition. To neutralize the effect of rolling velocity on the measured
value, Leonova must be programmed with shaft diameter (in millimetre or inch) and rotational speed
(in rpm).
The instrument will then calculate the initial value HDi , the starting point of the condition scale for
a particular bearing. The HDi can also be input directly or via the ISO bearing number. The condition
scale is graded in
normalized shock values, HDn.
Leonova samples the shock pulse amplitude over a period of time and displays:
• the maximum value HDm for the small number of strong shock pulses.
• the carpet value HDc for the large number of weaker shock pulses.
• the status dot which is green for HDm up to 20 HDn = good condition, yellow for 21-34 HDn =
caution, red for 35 HDn and more = bad operating condition.
The maximum value HDm defines the bearing’s position on the condition scale. The difference between
HDm and HDc is used for a finer analysis of the causes for reduced or bad condition.
When you set the HDi to ‘0’, Leonova will take an unnormalized reading in dBsv (absolute shock values).
The condition zones do not apply. This method is used for comparative reading on different bearings
and/or other shock pulse sources.
Normalized condition readings
Absolute scale
(shock value)
Normalized scale
(condition)
HDi = Initial value of a bearing
HDc = Carpet value (weak pulses)
HDm = Maximum value (strong pulses)
HDn = Unit for normalized shock level
dBsv = Unit for absolute shock level