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Corona Probe

Accurate Location of Partial Discharge in Rotating Machinery

Model PPM-97

  • Offline PD test for locating activity in the winding
  • Precisely locates PD to a particular slot and position
  • Locate partial discharge with the winding energized phase by phase
  • Portable, light-weight and easy to use
  • Recommended in IEEE ® Std 1434 


The Corona Probe Model PPM-97 is a portable battery operated instrument for off-line detection of partial discharge in rotating machinery. The instrument with its ferrite probe is designed to measure negative corona pulses. The corona probe test is a valuable aid for detecting the presence of abnormal partial discharging in stator coil insulation. It is one of the best tools for pinpointing the exact location of PD activity within the stator winding.

The PPM-97 supplements on-line PD measurements by more precisely locating the PD to a particular slot and position, with the winding energized phase by phase with a high voltage AC source. Alternatively it can be used as a stand-alone PD test for locating activity in the winding where no other PD information is available.


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  • Tuned to corona pulse bandwidth
  • Battery operated
  • Light-weight and portable



Bandwidth 0.5 – 10 MHz
Pulse Polarity 0 / 10 / 30 / 100 / 1000 mA Peak with off position
Effect of Battery Voltage Reads only negative pulses, or the negative swing of ringing pulses. Reading decreases approximately 10% as the battery output drops from 9 V to 7 V. The instrument will operate satisfactorily if the battery voltage is > 6 V
Dimensions (meter only) 9cm x 15.5cm x 4.5cm (3 1/2 ” x 6 1 / 8 ” x3/4 ”)
Weight (meter only) 445 grams (1 lb)
Probe Length 91cm (36”)
Input Connection BNC receptacle
Ground Connection Metal 5 way binding post
Batteries 9 V long-life (2)

*Specifications are to change without notice. 

Kit Contents

  • PPM-97 Peak Pulse Meter
  • Probe
  • Ground Strap
  • Carrying Case
  • Operating Manual