Edited by Stephen J. Mraz
The new GS102301 gear-tooth speed sensor from Cherry, a subsidiary of ZF Corp. with headquarters in Pleasant Prairie, Wis., uses Hall-Effect technology to detect gear teeth and their speed, provided the gears are made of a ferrous material. (The company recommends gears made of low-carbon, cold-rolled steel with gear teeth at least 0.2-in. tall, 0.1-in. wide, 0.25-in. thick, and spaced 0.4 in. apart for best results.) The near-zero-speed sensor operates in temperatures ranging from –40 to 140°C, and meets IPC68 standards for water immersion. It has also been tested for environmental exposure per SAE J1455, so it can withstand immersion in engine and transmission oils. The sensor’s circuity protects it from EMI and ESD, so it can withstand electrostatic discharges of up to 15 kV (contact discharge). The device measures 2.8-in. long and comes in a straight, threaded housing that fits into a standard M20 × 1.5 O-ring port. Installation torques can be as high as 15 lb-ft. The housing is Stanyl plastic, which resists environmental extremes, making it well suited for speed sensing in transmissions, engines, and brakes. It needs at least 3 mA and between 5 and 30 Vdc to operate.