CIRCUIT BREAKER 3713981 - Caterpillar

For case hardened and ground surfaces:
Due to the sensitivity required to locate the grinding cracks, inspection of case hardened and ground surfaces require that the yoke is applied so that the magnetic field is 1.57 rad (90°) to the expected direction of the indications. Also, due to the increased sensitivity resulting when the yoke is energized, the yoke is not moved until the evaluation is completed in the first direction. An AC yoke shall be used. See Illustration 66 for an example of yoke placement.
Visually inspect for indications of discontinuities using the proper illumination.
Record the size and shape of any discontinuities found.Ultrasonic Testing (UT)
Refer to Tooling and Equipment Table 3 for part numbers.
All personnel involved in ultrasonic examinations shall be qualified to Level 2 in accordance to standards stated in Table 23.
Ultrasonic testing (UT) is a method of Non-Destructive Testing (NDT) using short ultrasonic pulse waves (with frequencies from 0.1-15 MHz up to 50 MHz) to detect the thickness of the object. Ultrasonic testing consists of an ultrasound transducer connected to a diagnostic machine and passed over the object being inspected.
There are two methods of receiving the ultrasound waveform from the transducer: reflection and attenuation.a. Reflection - Ultrasonic pulses exit the transducer and travel throughout the thickness of the material. When the sound waves propagate into an object being tested, the waves return to the transducer when a discontinuity is discovered along the sonic path. These waves continue and reflect from the back surface of the material to project the thickness of the material.b. Attenuation - A transmitter sends ultrasound through one surface, and a separate receiver detects the amount that has reached it on another surface after traveling through the medium. Any discontinuities or other conditions within the medium will reduce the amount of sound transmitted, revealing the presence of the imperfections.Eddy Current Testing
Illustration 67 g06090873
Eddy-current testing
All personnel involved in Eddy Current examinations shall be qualified to Level 2 in accordance to standards stated in Table 23.
Eddy-current testing (ET) is a Non-Destructive Testing (NDT) method in which eddy-current flow is induced in the test object. Changes in the flow caused by variations in the specimen are reflected in to a nearby coil or coils for subsequent analysis by suitable instrumentation and techniques. Major applications of eddy-current testing are surface inspection and tubing inspections.Radiographic Testing
Illustration 68 g06090892
Radiographic Testing
All personnel involved in radiographic examinations shall be qualified to Level 2 in accordance to standards stated in Table 23.
Illustration 69 g00008666This process is dangerous. Only qualified personnel and test equipment should be appointed to perform this type of testing.Radiographic testing (RT) is a Non-Destructive Testing (NDT) method in which short wavelength of electromagnetic radiation is used to penetrate materials to find hidden discontinuities such as cracks. In radiographic testing, the test object is placed between the radiation source and the film, or x-ray detector. The electromagnetic radiation will penetrate the thickness of the test object and, when all the way through, will project onto the film any indications that have been in the