VRS Passive

Magnetic Speed Sensor Specs

• Frequency range: to above 100 kHz
• Temperature ranges: Standard & Extended, High temp & cryogenic sensors, -450 to 850° F (-270 to 454° C)
• Air Gaps:
  Magnet speed sensors: Recommended air gap between the magnetic sensor and the target is 0.005″ to 0.015″ typical, air gaps up to .25″ are possible depending on target velocity and mass
  Inductive speed sensors: 1” max depending on magnetic field strength
• Shock and vibration resistant – reliable in oily, wet and harsh environments;
• Sensor sizes: popular standard and metric thread and diameter sizes
• Shell Material: 303 Stainless Steel; other materials available

Magnetic Speed Sensor Applications:

SPECTEC’s magnetic speed pickups are sensitive, yet very reliable in harsh speed sensing environments that require shock-proof sensors. Applications of magnetic sensors are in wheel speed sensor, vehicle speed sensor, counting and position sensing in industrial applications, such as on conveyer belts.

Magnetic sensors are used with targets such as: slotted wheels, sprockets, and bolt heads.

Other applications for magnetic speed sensors is as ATV tachometer sensors; vehicle speed sensors, truck transmission and ABS sensors, locomotive traction sensors, and marine transmissions; in ABS brake systems for wheel slip and traction control; construction equipment transmission and tachometer applications; and in vehicles for engine RPM, speed and automatic transmission sensors.

SPECTEC magnetic speed sensors are used as high temperature race car sensors, applications on pipelines and oil fields around the world, OEM replacement locomotive traction sensors on commuter railroads, as well as in the moist, corrosive and noisy electrical environments of ships at sea.

Contact us for your custom magnetic speed sensors needs.

Magnetic Speed Sensor Principles of Operation:

The signal output of a magnetic speed sensor is caused by the excitation of its inductive coil by a passing target. As a ferrous actuator, such as a wheel’s gear or a turbine’s blade, moves past the magnetic sensor, the actuator’s surface discontinuity (i.e. a gear tooth) excites a voltage in the pickoff coil, producing an electrical analog wave.

The frequency and voltage of the analog signal is proportional to actuator velocity (like an AC-generator). Each passing discontinuity in the target causes the magnetic sensor to generate a pulse.

The cyclical pulse train created by a vehicle’s rotating gear, a flow meter’s turbine blade or a cotter key slot can be read by counters, meters or governing instrumentation.

Variable Reluctance Sensors – VRS Sensors

SPECTEC’s family of variable reluctance speed sensors for standard and custom applications

VRS Sensors Specifications

• Frequency range: to above 100 kHz
• Shock and vibration resistant and reliable in oily, wet and harsh environments
• Temperature Ranges: Standard and Extended, High temperature & cryogenic sensors, -450 to 850° F (-270 to 454° C)
• Easy installation and long maintenance-free life;
• Available in all popular standard and metric sizes
• Air Gaps:
  Magnet types: Recommended air gap between the VR speed sensor and the target is 0.005″ to 0.015″ typical, air gaps up to .25″ are possible depending on target velocity and mass
  Inductive types: 1” max depending on magnetic field strength
• Shell Material: 303 Stainless Steel; other materials available
• VR speed sensors spec sheet

Specialized VR Sensors:

• Intrinsically Safe to Zone 0
• Dual output
• Additional output for temperature available
• Hermetically-sealed and sanitary for food processing applications

SPECTEC’s line of DIGISPEC digital VR speed sensors, pulse amplifiers and frequency to voltage converters are available for applications requiring digital or other sensor outputs.

Variable Reluctance Speed Sensors Applications:

SPECTEC variable reluctance sensors are found in high pressure installations, the harsh environments of oil fields around the world, and in moist, corrosive and noisy electrical environments of ships at sea. Applications of passive VR speed pickups are as vehicle speed sensors, wheel speed sensors, counting and position sensing in industrial applications, such as on conveyer belts. VR sensors are used with such targets as: slotted wheels, sprockets, and bolt heads. Other applications for SPECTEC VRS sensors are: ATV tachometer sensors; truck, railroad and marine transmissions; in ABS brake systems for wheel slip and traction control; construction equipment transmission and tachometer applications; and in vehicles for engine RPM, speed and automatic transmission sensors.

Principles of VR Speed Sensor Operation:
The signal output of a VR speed sensor is caused by the excitation of its inductive coil by a passing target. As a ferrous actuator, such as a wheel’s gear or a turbine’s blade, moves past the sensor, the break in the actuator’s surface (i.e. a gear tooth) excites a voltage in the VR coil, producing an electrical analog wave. The frequency and voltage of the analog signal is proportional to actuator’s velocity. Each passing discontinuity in the target causes the VR sensor to generate a pulse. The cyclical pulse train created by a vehicle’s rotating gear, a flow meter’s turbine blade or a cotter key slot can be read by counters, meters or governing instrumentation.

Magnetic Speed Sensors Specifications

SPECTEC Magnetic speed sensors are sensitive, shock resistant and very reliable in harsh environments. These VR sensors are used as transmission sensors, diesel engine governor sensors and output shaft sensors. These VR sensors can be used with PA-20 signal conditioners for digital output.

Download Spectec Magnetic Speed Sensors Spec Sheet (PDF format) or the individual model spec sheets below.

Dual Output Magnetic Speed Sensors available in the same housing configurations as single output models..

Contact Spectec for custom magnetic speed sensors or OEM replacement VR sensors – or complete and submit our online Information Request Form.

High temperature speed sensors (up to 454° C) are sensitive, shock resistant & reliable for high temp applications in harsh environments, such as race car engines and transmissions. SPECTEC’s high temperature magnetic speed pickups are used as transmission sensors, engine governors, output shaft sensors and flow meter sensors.

SPECTEC’s high temperature magnetic pick-ups are standard in 5/8-18, 11/16-24 and 3/4-20, and M18 shell sizes.

High temperature magnetic sensors are available with RTD100 or NTC10 temperature sensors for dual output capability.

Contact Spectec’s engineering and design team for custom size high temperature magnetic speed sensors. Our engineers help you meet your high temp speed sensor needs.

SPECTEC is an ISO 9000 certified OEM manufacturer of aftermarket heavy equipment speed sensors, generator, engine and transmission speed sensors, and traction sensors for use in rough environments and many heavy duty commercial uses.

SPECTEC’s seasoned engineering staff designs the most dependable diesel engine speed sensors for the most demanding work environments.

Diesel Engine Speed Sensors

Our diesel engine speed sensors are replacement sensors for Woodward magnetic pickups, AMBAC, American Governor sensors for standard Cummins and Caterpillar diesel truck engines and diesel generators. Check our Speed Sensor Cross Reference page to find popular sensor replacements.

Mil Spec Magnetic Speed Sensors

SPECTEC’s stringent quality control and attention to detail has led to a successful relationship with our military customers. SPECTEC has been manufacturing mil spec magnetic speed sensors for the military since 1994.

Heavy Equipment Speed Sensor Engineering

Heavy equipment is used in situations that test a traction or speed sensor’s capability. SPECTEC has been re-engineering and manufacturing OEM sensors for our customers to help them keep their equipment working in the mines, in desert terrain, on train tracks or on construction sites where they belong, keeping them out of the repair area.

Contact Spectec’s engineering and design team about your heavy equipment traction and speed sensor needs – or complete and submit our online Information Request Form.

SPECTEC speed, traction and positioning sensors are designed and built for your heavy duty applications.

Dual output magnetic speed sensors are designed for pulse security applications where a redundant high reliability output is a must. These speed sensors can be used in place of two separate sensors, providing component and installation savings.

SPECTEC’s dual output magnetic speed pickups are used as transmission sensors, output shaft sensors and flow meter sensors.

Dual output speed sensors are available with an integral RTD100 or NTC10 temperature sensor option.

For dual output directional sensors with digital output see our Quadrature speed sensors and dual output Hall effect sensors

Contact Spectec for custom dual output magnetic speed sensors.