PAIRS OF PITS

Adjacent defects make signal analysis difficult because the leakage fields overlap and affect each other. The following buttons show signals from a small individual pit and a pair of pits: each is 50-percent deep by 1-inch wide by 1-inch long. Separation is either circumferential, axial, or diagonal:

Adding a second pit in the hoop direction leads to a single signal with a much higher amplitude than for an individual pit. Adding a second pit in the axial or diagonal direction produces two signals that overlap somewhat and which have slightly lower amplitudes than the individual pit.