An inductive transducer includes first and second relatively movable members, the first relatively movable member having a plurality of windings and the second relatively movable member having a winding. The windings of the first relatively movable member each have a pair of terminals and are each arranged in a pattern comprised of a first section coupled to one of the terminals and a second section coupled to the other terminal and to the first section. Each section includes a plurality of conductors oriented substantially parallel to one another wherein immediately adjacent conductors of such section are capable of conducting current in opposite directions and are coupled to one another by an end-segment arranged substantially perpendicular to the conductors. Each end-segment of the first section is spaced closely adjacent and substantially parallel to an end-segment of the second section, and each conductor of the first section is spaced closely adjacent and substantially parallel to a conductor of the second section adapted to conduct current in the opposite direction as such conductor of the first section. The winding of the second relatively movable member is similar, except its first section has alternate end-segments thereof spaced closely adjacent and substantially parallel to alternate end-segments of its second section, and each conductor of its first section is substantially aligned longitudinally with a conductor of its second section adapted to conduct current in the same direction as such conductor of its first section.
A transducer, especially suitable for monitoring welds (22), in a sodium-cooled nuclear reactor, has two plates (11, 12) in sliding face contact with parallel slots (13, 14) holding inductively coupled conductors (15, 17). One plate (12) is connected directly to one side of the weld and the other plate (11) is connected via an arm (23) and spacer (24) to the other side of the weld. Multiple slots and conductors can be employed to remove ambiguity from measured signals from the transducer. Multiple transducers can be employed in a scanned X-Y matrix.
In an electromagnetic induction type displacement sensor, two coil patterns are formed on a substrate included in a scale. The coil patterns alternate with each other in the sensing direction of the sensor and are deviated in spatial phase from each other by a quarter pitch. An idle pattern portion is included in one or both of the two coil patterns in order to provide them with the same impedance. Even when sinusoidal voltages, which are different in phase by 90 degrees, are respectively applied to the coil patterns, the resulting magnetic fields are identical and insure accurate displacement detection.
