Abstract: A system (10) for determining the thickness of a magnetic flux conductive clad material over a magnetic flux conductive base material of different permeability applies on alternating voltage (96) to the primary winding (52) of an incomplete core-type transformer (54). The secondary winding (40) voltage to primary winding (52) voltage ratio is determined with the material being clad-thickness measured (56) completing the incomplete core (54). The voltage ratio is a nondestructive measurement of the thickness (64) of the clad material. The preferred embodiment applies a constant voltage alternating voltage power source (18) to the primary winding (52). This obviates the need to determine the ratio of voltages. The secondary winding (40) voltage is a direct nondestructive measurement of the thickness (64) of the clad material.

Abstract: An electrical circuit (102, 102') employable in cooperative association with welding means (90) for purposes of effecting the application of a weld deposited rib on the inner wall surface of a boiler tube (10), and through the use of which control is exercised over the size, pitch and pattern of the rib. For purposes of exercising control over the rib size and the rib pitch, the subject electrical circuit (102, 102') includes first (104, 104'), second (106) and third (108) electronic speed controller means that are connected in electrical circuit relation to the rotational motor means (92) of the welding means (90), the linear travel motor means (94) of the welding means (90), and the wire feed motor means (96) of the welding means (90), respectively.