An apparatus comprises a first substrate and two coils supported by the first substrate and arranged next to each other, the coils configured to each generate a magnetic field which produces eddy currents in and a reflected magnetic field from a conductive target, the two coils arranged so their respectively generated magnetic fields substantially cancel each other in an area between the coils. One or more magnetic field sensing elements are positioned in the area between the coils and configured to detect the reflected magnetic field.

The purpose of the present invention is to provide a rotation speed detection device which achieves improved detection accuracy regardless of a compressor and the operating state of the compressor, and enables the prevention of the breakage of a detection unit. A rotation speed detection device for a compressor, wherein a detection unit for detecting full blades and splitter blades that are blades approaching a compressor casing of the compressor in response to a change in the inductance of a magnetic field is provided. The detection unit is provided in an overlap region in which the full blades and the splitter blades that are all blades can be detected and the exposure pressure is in the range of a gauge pressure of one atmosphere or less.

The purpose of the present invention is to provide a rotation speed detection device which achieves improved detection accuracy regardless of a compressor and the operating state of the compressor, and enables the prevention of the breakage of a detection unit. A rotation speed detection device for a compressor, wherein a detection unit for detecting full blades and splitter blades that are blades approaching a compressor casing of the compressor in response to a change in the inductance of a magnetic field is provided. The detection unit is provided in an overlap region in which the full blades and the splitter blades that are all blades can be detected and the exposure pressure is in the range of a gauge pressure of one atmosphere or less.

A transducer for an inductive displacement sensor includes a secondary winding of 2N turns of alternating directions extending in a zone of length D.sub.tot, the winding including: a first coiled conductive section forming N half-turns, extending between a first end of the winding, situated at the midpoint of the length D.sub.tot, and a first point of the winding, situated at one end of the length D.sub.tot; a second section forming N half-turns, extending between the first point and a second intermediate point situated at the midpoint of the length D.sub.tot; a third section forming N half-turns, extending between the second point and a third intermediate point situated at a second end of the length D.sub.tot; and a fourth section forming N half-turns, extending between the third point and a second end of the winding situated at the midpoint of the length D.sub.tot.

A transducer for an inductive displacement sensor includes a secondary winding of 2N turns of alternating directions extending in a zone of length D.sub.tot, the winding including: a first coiled conductive section forming N half-turns, extending between a first end of the winding, situated at the midpoint of the length D.sub.tot, and a first point of the winding, situated at one end of the length D.sub.tot; a second section forming N half-turns, extending between the first point and a second intermediate point situated at the midpoint of the length D.sub.tot; a third section forming N half-turns, extending between the second point and a third intermediate point situated at a second end of the length D.sub.tot; and a fourth section forming N half-turns, extending between the third point and a second end of the winding situated at the midpoint of the length D.sub.tot.

A target for an inductive displacement sensor is provided, including a plurality of conductive patterns distributed along a zone having a dimension D.sub.tot in a direction, the patterns being defined by the overlay of at least a first set of elementary periodic patterns having a period approximately equal to D.sub.tot/N, including N first elementary conductive patterns of a dimension approximately equal to D.sub.tot/2N in the direction, regularly distributed along the zone, and of a second set of elementary periodic patterns having a period approximately equal to D.sub.tot/(N+r), including N+r second elementary patterns of a dimension approximately equal to D.sub.tot/2(N+r) in the direction, regularly distributed along the zone, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N1, wherein first and second elementary conductive patterns overlap at least partially.

A target for an inductive displacement sensor is provided, including a plurality of conductive patterns distributed along a zone having a dimension D.sub.tot in a direction, the patterns being defined by the overlay of at least a first set of elementary periodic patterns having a period approximately equal to D.sub.tot/N, including N first elementary conductive patterns of a dimension approximately equal to D.sub.tot/2N in the direction, regularly distributed along the zone, and of a second set of elementary periodic patterns having a period approximately equal to D.sub.tot/(N+r), including N+r second elementary patterns of a dimension approximately equal to D.sub.tot/2(N+r) in the direction, regularly distributed along the zone, where N is an integer greater than or equal to 2 and r is a positive integer, different to zero and less than or equal to N1, wherein first and second elementary conductive patterns overlap at least partially.

An eddy current sensor for a rotary shaft and a rotary shaft apparatus. The eddy current sensor includes: a housing; one or more position detecting probes provided on the housing; and a rotating speed detecting probe provided on the housing. The eddy current sensor integrates the position detecting probe and the rotary speed detecting probe, such that while the eddy current sensor is detecting position displacement of the rotary shaft, the eddy current sensor may also simultaneously detect the rotating speed of the rotary shaft, which facilitates detecting and monitoring the rotary shaft more comprehensively. The detected position data and rotating speed data of the rotary shaft correspond to each other at any time, such that the working state of the rotary shaft may be analyzed more intensively.

An eddy current sensor for a rotary shaft and a rotary shaft apparatus. The eddy current sensor includes: a housing; one or more position detecting probes provided on the housing; and a rotating speed detecting probe provided on the housing. The eddy current sensor integrates the position detecting probe and the rotary speed detecting probe, such that while the eddy current sensor is detecting position displacement of the rotary shaft, the eddy current sensor may also simultaneously detect the rotating speed of the rotary shaft, which facilitates detecting and monitoring the rotary shaft more comprehensively. The detected position data and rotating speed data of the rotary shaft correspond to each other at any time, such that the working state of the rotary shaft may be analyzed more intensively.

A method of analyzing a structural condition of a machine is described. The method includes determining a position of a portion of a machine, a rotating shaft, a fluid transfer system, or a reciprocating machine in operation; collecting an image of the portion with an image collector; synchronizing the determined position of the portion with the collected image of the portion; amplifying the synchronized image; and storing the amplified image to a memory. Related apparatuses, systems, storage media, techniques and articles are also described.