Testing Services

Generator In-Situ Inspections

We perform generator in-situ testing with the field in the stator (in-situ) using the Miniature Air Gap Inspection Crawler (MAGIC) robot. The MAGIC robot performs all tests typically performed with the field removed from the stator, including:

• Visual inspection of field and stator surfaces
• Wedge tightness test
• El Cid test
• Radial bar jacking test
• Capacitance mapping test

The MAGIC robot saves time and eliminates the risks associated with removing the field. We perform generator in-situ testing on all turbine-generators, regardless of manufacturer, as long as the retaining ring-to-stator entrance gap is greater than 0.5 in (1.27 cm).

• Generator In-Situ Inspection (334KB PDF)

Generator Rotor Boresonic Inspections

A generator rotor boresonic inspection consists of a series of interrelated non-destructive tests on the integral turbine/generator rotor to determine its fitness for duty and return to service. The comprehensive inspection report includes a recommended re-inspection interval. We perform generator rotor boresonic inspections on all generator rotors with bore holes regardless of manufacturer.

The tests include:

• A rotor bore magnetic particle test, which detects bore surface cracking or near-surface defects
• A rotor periphery ultrasonic test, which we perform from the rotor outside diameter through the rotor cross section to locate any defects

• Boresonic inspection (1.6MB PDF)

Retaining Ring Inspections

A retaining ring inspection consists of a series of tests to determine the integrity of the generator retaining rings. Although they are primarily used on 18-5 (18 percent magnesium, 5 percent chromium) rings, the test packages are also applicable to other materials. We perform retaining ring inspections on all generator and excitation rotors regardless of manufacturer.

The tests include:

• Ultrasonic tests for rings on the field
• Eddy current tests for rings removed from the field
• Liquid penetrant tests on the ring outside diameters in conjunction with ultrasonic tests, and on the locking ring areas in conjunction with eddy current tests

• In Place Retaining Ring UT (552KB PDF)

Generator Rotor Slot Tooth Eddy Current Inspection

An Eddy current examination of the rotor for the slot tooth cracking meeting the inspection requirement relative to TIL 1292 and can help minimize the risk of outage extension for emergent rotor tooth repairs. The generator slot tooth inspection can be performed during an outage after the retaining rings and slot wedges have been removed. The test employs eddy current coil arrays on both sides of a probe to provide complete coverage of the slot dovetail. This configuration allows the entire length of the slot to be inspected in a single manual scan and provides an accurate assessment of the generator dovetail condition. Advantages of this system include:

• Completion of the inspection in two 12-hour shifts
• No special preparations required, only basic cleaning of the slot dovetail area
• No contamination of the winding
• More sensitive readings than other NDE methods
• Permanent record provided with data stored on CD

• Generator Rotor slot tooth Eddy current inspection (513KB PDF)

Custom Test Development

GE technicians test and maintain the world's largest installed turbine-generator fleet using state-of-the-art flaw detection equipment and procedures. When you have unique testing requirements, we can put the full scope of our testing and evaluation expertise to work for you.

Experienced GE technicians can develop custom test procedures for:

• New equipment and part designs
• Unique equipment features
• Inspection of repair work, such as weld repairs

Download More Information

• Generator In-Situ Inspections (659KB PDF)
• GE Generator Rotor Design, Operational Issues and Refurbishment Options (924KB PDF)

For More Information

• Send email to commsu@ps.ge.com