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SPM Monitoring 

Toowoomba Bearings & Hydraulics offers a unique SPM Monitoring Service designed to maximize machine productivity, through early detection of bearing wear and failure.

SPM is an abbreviation for the Shock Pulse Method, which is a patented technique for using signals from rotating rolling bearings as the basis for efficient condition monitoring of machines.

From the innovation of the method in 1969 it has now been further developed and broadened and is now a worldwide accepted philosophy for condition monitoring of rolling bearings and machine maintenance.

They make an excellent foundation for a proactive approach to maintenance, integrated in your normal maintenance activities and providing you with an overall picture.

Our equipment detects fault conditions well in time for planned maintenance and repairs, causing none or minimal interruption of the production process. Immediate and evaluated condition information is presented as green yellow red condition codes for instant and easy recognition of trouble spots. This greatly improves the effectiveness of available staff resources.

Benefits of Shock Pulse Monitoring

  • Reduces unplanned stoppages

  • Maximizes asset productivity

  • Eliminates secondary damage

  • Shortens repair times


Uniqueness of Shock Pulse Monitoring

  • SPM specializes in determining accurate information on the mechanical condition of the bearing surfaces as well as the state of lubrication on the bearing throughout the life of the bearing.

  • As any machine with metal to metal contact will give shock pulses it is useful for analysis of other machines like screw compressors, gear boxes, lobe compressors, centrifuges, purifiers, centrifugal pumps apart from motors.

  • SPM also gives an indication of faulty installation and alignment.

How does SPM Work ?

Whether new or old, any bearing generates shocks in the interface between the loaded roller element and the race way. Initially these shocks or vibrations are subtle and hardly felt till already damage is done, but these are captured routinely by the SPM machine which tells about the condition of the bearings, the state of lubrication and the maintenance interval required. This type of monitoring and maintenance based on this evaluation is called as Condition Monitoring System or Condition Based Monitoring.









The shock pulses are measured by accelerometers with filters. The accelerometers have piezoelectric crystals so designed that they resonate at a frequency of 36 KHz which corresponds to the frequency of the pure shock pulses. This helps the accelerometers to measure both shock pulse as well as vibration making other vibration pens only measuring vibration obsolete.

The amplitude of shock pulses measured by the SPM meter is due to the following factors:

  • Rolling velocity which is a function of speed or rotation and size of bearing.

  • The thickness of the oil film, which in turn depends on preload and the quantity of oil supplied as well as the viscosity of the oil.

  • The alignment of the system. That means between the prime mover and the load.

  • Other mechanical factors like roughness of the raceways, the stress and damages.


The shocks are received by the SPM transducer which then gives an output signal proportional to the magnitude of the shock felt. The SPM meter measures the shock pulses per second and then lowers its threshold so that two amplitude levels are discovered, first the decibel carpet value of 200 shocks per second and secondly, the maximum level of incoming shock under 2 seconds.

The decibel carpet value gives an indication of the condition of the lubrication and the peak value gives the extent of bearing damage.

The peak value can be ascertained by increasing the threshold value till no signal is received. In this equipment the noise generated due to the rolling velocity is negated by entering the shaft diameter and RPM of the motor. This gives an accurate condition assessment of the machine being monitored.

The amplitude of the shock is a function of the rolling element and the instrument measures the absolute value and subtracts from it the expected shock value from a good bearing at similar speed. This gives us an indication of the bearing operating condition.

If you want to take a more ‘proactive’ approach to machine and bearing maintenance, then please call 1300 321 829 or Contact Us.

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