Shaft Tachometer

Electro-Sensors, Inc. announced the ST420, a loop-powered, stainless steel analog shaft tachometer that detects magnetic pulses from a rotating shaft-mounted pulser disc or wrap. Measuring 18mm in diameter, the ST420 uses quartz crystal-based digital processing to convert pulses to a continuous 4-20mA analog signal directly proportional to the pulse frequency. According to the company, the result is a plug-and-play solution that allows users to accurately monitor rotating shaft speed.

The shaft tachometer has been tested by UL to the standards UL913 and CAN/CSA C22.2 No 157-92 (Intrinsic Safety), assuring it provides an intrinsically safe solution for Class I (Groups C & D) and Class II (Groups E, F & G) environments, when used with an approved I.S. barrier. Its magnetic pulse detector, signal processing capability and 2-wire loop-powered 4-20 mA circuitry are combined into a stainless steel M18x1 sensor housing. The ST420 resists harsh plant environments and is rated NEMA 4X/IP67.

Also available is the ST420-DI* shaft tachometer, which delivers shaft speed monitoring by incorporating the above features into a rugged M18x1 sensor housing with a built-in ½-inch NPT conduit port. This dust ignition-proof model is designed for Class II (Groups E, F & G) environments.
www.electro-sensors.com