Capacitive Air Gap Sensor

Capacitive Air Gap Sensors for Continuous On-line Air Gap Monitoring

Product Overview

Capacitive Air Gap Sensors measure the distance between the rotor and stator in hydroelectric generators to avoid reduced efficiency or damage caused by off-center or out-of-round conditions.

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Works with the Following Assets
Assists with the Following Type of Monitoring

Online monitoring of the air gap with Iris Power Capacitive Gap Sensors (CGS) can provide important information about the generator condition by measuring the distance between the rotor and the stator winding.  Monitoring allows air gap issues to be identified and corrected before an in service failure can occur.

Product Details


  • Capacitive Sensor Technology
  • Output directly proportional to the air gap distance (pole profile)
  • Easy to install and no special calibration needed
  • Low Profile (3 types)
  • High Temperature Stability
  • Immune to magnetic fields, dust, oil, EMI, RFI
  • The air gap sensor comes in a kit with a signal conditioner, junction box and mounting epoxy


Three types available:


  • 135 x 32 x 1.7 mm
  • maximum sensor distance from top of core –  0.5 m (1.6 ft)
  • Recommended range for nominal air gap – 5 mm to 12 mm


  • 230 x 32 x  1.7 mm
  • maximum sensor distance from top of core –  1 m (3.2 ft)
  • Recommended range for nominal air gap – 12 mm to 22 mm


  • 250 x 40 x  1.7 mm
  • maximum sensor distance from top of core –  1 m (3.2 ft)
  • Recommended range for nominal air gap – 22 mm to 47 mm

Get a Quote

Call us at +1 905.677.4824 or Toll Free at +1 888-873-4747 or fill out our online quote form below.

Learning Center

This Resource Library is designed to provide current, relevant resources that provide technical knowledge and practical solutions for owners and operators of rotating machines. We encourage you to use the search feature and filters to locate specific resources of interest.


Articles, Technical Papers, & Case Studies

Results of Destructive Analysis of Service-Aged Hydrogenerator Stator Winding Insulation

SUMMARY The insulation system in form-wound stator windings is exposed to electrical, mechanical and thermal stresses, in addition to ...



Hands-on, practical experience

Partial Discharge Course -Toronto, Canada

The objective of this Partial Discharge Seminar is to understand basic PD theory as well as the basics of stator…


IRMC 2023 June 26-29, 2023 - Royal Sonesta Houston, Houston, TX

IRMC 2023

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