AI-Tek (formerly AIRPAX) - Magnetic Speed Sensors
Passive Magnetic Speed Sensors rely on variable reluctance technology (VR) and are readily available from Automatic Controls Inc, on line catalog.
The Hall Effect Magnetic speed sensor can sense each change in target movement, regardless of speed, from near zero to 15 kHz frequency range, generating a steady pulse train of frequency proportional to target speed.
AI-Tek manufactures a complete line of bi-directional magnetic speed pick ups for industrial applications.
Optical Speed Sensors by Monarch are more versatile and application friendly than most speed sensors on the market. These optical sensors are manufactured from threaded stainless steel and feature a visible red LED light source and an "on-target" green LED indicator.
Principles of Operation:
The signal output of a magnetic speed sensor is caused by the excitation of its inductive coil by a passing ferrous target. As a ferrous actuator (speed sensing gear) moves past the magnetic sensor, the discontinuity in the surface of the gear (i.e. a gear tooth) excites a voltage in the pickup coil, producing an electrical analog wave. The frequency and voltage of the analog signal is proportional to surface velocity of the sensing gear. The operation is similar to an AC Generator. Each passing discontinuity in the target causes the magnetic sensor to generate a pulse. The cyclical pulse train created by the rotating gear, or a turbine meter blade can be read by various types of signal conditioners or process tachometers.
Sensing Gears, Mounting Brackets, Cable Assemblies and Connectors are available from Automatic Controls, Inc on line catalog.