Spectrol has produced an innovative design for a three-terminal voltage output device that integrates a Hall-effect sensor and a patented magnetic circuit to convert radial motion into a voltage-output signal. Standard electrical angles are at 60, 75, 90, 105, 120, 135, and 150 degrees. Standard linearity is ±2 percent with special linearities as low as ±0.25 percent.

Potential motion control applications for the sensor include construction vehicles, industrial controls, marine equipment, and material handling. The sensor can quality for underhood automotive use requiring high accuracy and repeatability. For off-road vehicles, it is especially useful for systems employing steering and throttle control, in-cab levers and pedals, and other applications requiring angular position and feedback.

The Spectrol Model 155 is a Noncontacting Position Sensor that can resolve rotation up to 180 degrees. Key: (1) terminals; (2) printed circuit board; (3) Hall-effect IC chip; (4) carrier; (5) bearing cap; (6) ring with magnet; (7) rotor; (8) C ring (2); (9) shim; (10) sleeve bearing; (11) housing.

The sensor is constructed so that a magnet is rotated around a Hall-effect IC at the center of rotation of a standard potentiometer-type housing. The changing magnetic field causes the output of the Hall device to swing from 0.5 to 4.5 V. Standard units require an input voltage of 5 V DC ±10 percent. A second input voltage option is available that allows a 5.5 to 24 V DC unregulated voltage source.

Because it is electrically noncontacting, with all circuitry and components encapsulated in epoxy, the sensor is immune to water, dirt, dust, lubricants, shock, and vibration, and will operate at 100-percent efficiency while submerged in salt water. The only components susceptible to wear are the shaft and bronze sleeve bushing. Minimum rotational life of the sensor is 50 million cycles with no side load. The bearing system, however, is extremely robust and will withstand substantial side loading while providing millions of revolutions of rotational life. The Hall-effect technology is contained in a package measuring 7/8 in. in diameter and 0.7 in. deep with a -32 threaded bushing. Maximum weight is 1.5 oz. The sensor is EMC-compliant, Class C, 200 V/m to 1 GHz.

The Spectrol Model 155 position sensor.

Specific applications include leveling and level suspension systems, especially those in oppressive environments; hydraulic actuator and valve positioning and feedback; feedback for angular position sensors; pressure sensing, even under constant dither; and any number of other systems and assemblies that involve radial or linear movement and motion control.

This sensor design was created by the Advanced Development Group at Spectrol Electronics Corp., 4051 Greystone Drive, Ontario, CA 91761, and colleagues from both Spectrol and Wabash Technologies, Inc., of which the former is a unit. For more information contact Brad Canfield at 1-800-624-8902; fax: (909) 923-6765; E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it..


Motion Control Tech Briefs Magazine

This article first appeared in the October, 1999 issue of Motion Control Tech Briefs Magazine.

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