Control and protection circuits have relied on variable reluctance technology for years. With few components and no moving parts, the passive magnetic speed sensors can provide a signal from the inside of an aircraft engine at temperatures approaching 425 degrees C or from the hub of an automobile wheel at high shock and vibration.
The Hall Effect sensor can sense each change in target movement, regardless of speed, from zero to 15 kHz frequency range, generating a steady pulse train of frequency proportional to target speed. Typically, each time a gear tooth (or any ferrous discontinuity) passes in front of the sensor the output changes state. This type of sensor is known as “P” type because it uses N-P-N transistor logic (as opposed to “N” type, which uses P-N-P transistor logic).
AI-Tek Instruments offers fast response and high-precision tachometers for monitoring and protection. Field programming allows easy installation and upgrading, while minimizing part number variations. Options include 0-20mAdc, 4-20mAdc, -20 to 0 to +20mAdc output, 5-digit display, RS485, 2 solid state relays, 2 mechanical relays, with standard, NEMA 4x or explosion proof enclosures.