AI-Tek 70085-1010-056

Technical Dossier

Product Details And Specifications

AI-Tek 70085 Series Technical Notes

The AI-Tek 70085 series of passive speed sensors occupies a well-established position in global heavy industry installations, including petrochemical refineries, nuclear power facilities, pulp and paper mills, steel rolling mills, and offshore platforms. These variable reluctance (VR) sensors operate without an internal power supply, generating a sinusoidal AC voltage signal proportional to the rotational speed of a ferromagnetic target wheel. Their passive architecture eliminates failure modes associated with active electronics, making them a preferred choice for safety-critical rotating machinery monitoring — turbines, compressors, pumps, fans, and conveyor drives — where signal reliability over decades of service is a primary specification requirement.

The 70085 series is manufactured by AI-Tek Instruments (formerly known as Airpax / Electro Corporation), a U.S.-based OEM with a long-standing catalog in industrial tachometry and speed sensing. The series covers a broad range of connector configurations, cable lengths, thread sizes, and temperature ratings, allowing direct cross-referencing against legacy installations without mechanical modification.

The Evolution of 70085 Architecture

The 70085 series traces its lineage to the Electro Corporation variable reluctance sensor designs of the 1970s, which were adopted widely in the first generation of DCS-integrated turbine control systems. When AI-Tek Instruments absorbed the Electro Corporation product line, the 70085 numbering convention was retained to preserve backward compatibility with existing plant documentation, spare parts lists, and DCS I/O wiring schedules.

Early 70085 variants used a two-wire flying lead output with a simple threaded body (typically 3/8-24 UNF or M18x1.5), designed for direct insertion into proximity housings on gear teeth or toothed wheels. Subsequent revisions introduced MIL-spec connector terminations (MS3106 series), extended temperature ratings (–55°C to +150°C), and potted construction for IP67 ingress protection. The current catalog spans both legacy connector types and modern M12 circular connector variants, ensuring compatibility across control system generations from Honeywell TDC 3000, Foxboro I/A Series, ABB Advant, and Emerson DeltaV installations.

AI-Tek 70085 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the AI-Tek 70085 passive speed sensor series. Each model is a variable reluctance sensor; functional differentiation is driven by connector type, cable configuration, thread specification, and temperature/environmental rating.

70085-1010-056: Passive VR speed sensor, 2-wire flying lead, 3/8-24 UNF thread, standard temperature range, general industrial use.
70085-1010-057: Passive VR speed sensor, 2-wire flying lead, extended 12-inch cable, 3/8-24 UNF thread, panel-mount compatible.
70085-1010-058: Passive VR speed sensor, 2-wire output, M18x1.5 metric thread body, IP65 rated, European plant standard.
70085-1010-060: Passive VR speed sensor, MS3106 MIL-spec connector, 3/8-24 UNF, potted construction, vibration-resistant.
70085-1010-061: Passive VR speed sensor, MS3106 connector, extended temperature –55°C to +150°C, suitable for turbine housings.
70085-1010-062: Passive VR speed sensor, MS3106 connector, M18x1.5 thread, high-temperature potted, refinery-grade.
70085-1010-065: Passive VR speed sensor, 2-wire shielded cable, 3/8-24 UNF, EMI-shielded for variable frequency drive environments.
70085-1010-070: Passive VR speed sensor, M12 4-pin circular connector, 3/8-24 UNF, IP67, modern DCS retrofit compatible.
70085-1010-072: Passive VR speed sensor, M12 connector, M18x1.5 thread, IP67, stainless steel body option.
70085-1010-075: Passive VR speed sensor, 2-wire, 3/8-24 UNF, extended 36-inch armored cable, hazardous area rated.
70085-1010-080: Passive VR speed sensor, MS3106 connector, 1/2-20 UNF thread, heavy-duty compressor and pump shaft monitoring.
70085-1010-082: Passive VR speed sensor, MS3106 connector, 1/2-20 UNF, high-output coil winding, low tooth-count target wheels.
70085-1010-085: Passive VR speed sensor, 2-wire flying lead, 1/2-20 UNF, standard temperature, paper mill and steel mill service.
70085-1010-090: Passive VR speed sensor, M12 connector, 1/2-20 UNF, IP67, nuclear plant qualified documentation available.
70085-1010-095: Passive VR speed sensor, MS3106 connector, M24x1.5 metric thread, high-vibration offshore platform specification.
70085-1010-100: Passive VR speed sensor, 2-wire, M24x1.5 thread, extended temperature, subsea and marine drive monitoring.

Quality Control for the AI-Tek 70085 Range

Each 70085 series sensor processed through DriveKNMS undergoes a structured verification protocol prior to dispatch. Coil resistance is measured against the OEM-specified nominal value (typically 150–2,500 Ω depending on variant) using a calibrated LCR meter. Insulation resistance between the coil winding and the sensor body is tested at 500 VDC to confirm potting integrity and absence of moisture ingress. Output voltage linearity is verified on a calibrated gear tooth test rig, confirming that the sensor generates a clean sinusoidal signal across the specified RPM range without harmonic distortion or signal dropout.