Generator End Ring Inspection Manipulator

The Phoenix PERM enables 100% scan coverage of the external surface of generator end rings without removing the rotor from the stator. PERM can be fixed into position by two operators in less than one hour and is capable of inspecting a large range of modern generator end rings.

Generator rotor end rings are amongst the most highly stressed and safety-critical components in power stations. End ring inspection has traditionally been difficult and has required the removal of the rotor from its stator and then the ring from the rotor. Operators using the PERM systems have reported savings of as much as €200,000 in a single inspection. Minimum of 28mm operating envelope – smaller envelopes are possible.

The Phoenix manipulator (PERM) enables operators to scan 100 percent of the rings, including the tapers, with all the components in place. As well as reduced risk of damage, this results in significant cost savings and downtime.

Current versions of PERM include the capability to scan with phased array and conventional ultrasonic probes and eddy current arrays to ensure thorough and fast inspections.

Phoenix has over two decades of experience in producing systems of this type and the PERM is used by major operators in power stations throughout the world.

Contact us and speak to one of our experts about the PERM.

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Generator End Ring Inspection Manipulator

Standard Kit

Corrosion Mapping Package

  • Circumferential drive assembly
  • Circumferential and axial drive support assembly
  • Axial drive transfer assembly (nominal sizes)
  • Axial drive leadscrew assembly pairs
  • Inboard end bridge
  • Outboard end bridge
  • Emergency stop assembly
  • Axial drive interface box
  • Circumferential drive interface box


  • Suitable for ring diameters 750mm to 2000mm and 1000mm long
  • Manipulator profile 36mm
  • Repeatability better than +/- 1mm
  • Scan speeds 75mm/s
  • Interchangeable probe holders include skew and taper units
  • Typical payload 5 probes
  • 48 volt/3amp DC servo motors with 5V incremental encoders