Hazardous Location Industrial VRS Magnetic Speed Sensors DESCRIPTION Hazardous Location VRS sensors are designed for use in The output signal of a VRS sensor is an ac voltage that varies locations where explosion-proof or intrinsically safe sensors in amplitude and wave frequency as the speed of the are required. monitored device changes, and is usually expressed in peak to peak voltage (Vp-p). Passive VRS (Variable Reluctance Speed) Magnetic Speed sensors are simple, rugged devices that do not require an One complete waveform (cycle) occurs as each target passes external voltage source for operation. the sensors pole piece. If a standard gear were used as a target, this output signal would resemble a sine wave if viewed A permanent magnet in the sensor establishes a fixed on an oscilloscope. magnetic field. The approach and passing of a ferrous metal target near the sensors pole piece (sensing area) changes the Honeywell also offers VRS sensors for general purpose, high flux of the magnetic field, dynamically changing its strength. output, power output, high resolution and high temperature, as This change in magnetic field strength induces a current into a well as low-cost molded versions. coil winding which is attached to the output terminals. FEATURES POTENTIAL APPLICATIONS Self-powered operation Engine RPM (revolutions per minute) measurement on Direct conversion of actuator speed to output frequency aircraft, automobiles, boats, buses, trucks and rail Simple installation vehicles No moving parts Motor RPM on oil and gas drilling equipment and Designed for use over a wide range of speeds machinery Adaptable to a wide variety of configurations Motor RPM measurement on drills, grinders, lathes and Customized VRS products for unique speed sensing automatic screw machines applications Process speed measurement on food, textile, paper, Housing diameters: 3/4 in, 5/8 in woodworking, printing, tobacco and pharmaceutical Housing material/style: stainless steel threaded industry machinery Terminations: MS3106 connector, preleaded Motor speed measurement of electrical generating Output voltages: 30 Vp-p to 60 Vp-p equipment in grain elevators, sawmills and other potentially explosive environments Speed measurement of pumps, blowers, mixers, exhaust Gear speed measurement Hazardous Location 3/4 INCH EXPLOSION-PROOF SENSORS (All dimensions for reference only. mm/ in ) When properly installed using the explosion containment method, all 3070X and catalog listings on this page are certified for use in hazardous locations as follows: Class I, Groups A, B, C, D Class II Groups E, F, G Class III. These catalog listings have been tested to and meet the requirements of applicable U.S. and Canadian specifications for the locations described above. General Specifications Test Condition Specifications Parameter Characteristic Parameter Characteristic Parameter Characteristic Min. output voltage 60 Vp-p Inductance 115 mH max. Surface speed 25 m/s 1000 in/s Coil resistance 191 Ohm to 280 Ohm Gear pitch range 12 DP (module 2.11) Gear 8 DP or coarser (module 3.17) Pole piece 4,75 mm 0.187 in Optimum actuator 8 DP (module 3.17) Air gap 0,127 mm diameter ferrous metal gear 0.005 in Min. surface 0,38 m/s 15 in/s typ. Max. operating 40 kHz typ. Load 100 kOhm speed frequency resistance Operating temp. -73 C to 93 C Vibration Mil-Std 202F range -100 F to 200 F Method 204D Mounting thread 3/4-20 UNEF-2A Termination 18 AWG PVC-Insulated Leads Catalog Thread Weight 24,05 31,75 3000 MIN A 1.00 1.250 120.00 Listing Length (A) 1/2-14 NPT 3070A 45 mm 1.8 in 294 g 10.5 oz 3070A35 88 mm 3.5 in 322 g 11.5 oz BLIND END SHELL POLE PIECE 2 www.honeywell.com/sensing