Speed Sensors

Variable Reluctance (Inductive)

Variable reluctance (inductive) sensors are designed to use electromagnetic induction to measure the speed of a rotating ferrous object such as a crank or cam trigger. Using a small internal magnet and inductive coil that generates an analogue voltage as the magnetic field changes whilst passing over the ferrous tooth of the rotating object. When connected to an interface unit or supporting ECU it is possible to determine rotational speed.

Resistance:630Ω to 730Ω
Operating temperature:-10°C to +200°C
Cut-in speed:40rpm
Typical applications:Crank speed, Cam speed, Gear speed, Wheel speed

Zero Speed Hall

Hall sensors are designed to use the speed of a rotating ferrous object such as a cam trigger or gear tooth. Due to their design they allow operation down to zero speeds, independent of air gap. Using a small internal magnet, the magnetic field changes whilst passing over the ferrous tooth of the rotating object a producing a digital signal. When connected to an interface unit or supporting ECU it is possible to determine rotational speed.

Output: Digital
Operating temperature: -10°C to +165°C
Range: 0Hz to 10KHz
Air gap: 1.5mm (typ) 2.5mm (Max)
Typical applications: Cam, Gearbox, Wheel speed

Differential Wheel Speed

Differential Hall Effect sensors are designed to measure the speed of a rotating ferrous object such as a wheel trigger or gear tooth. Using a small internal magnet and a differential hall device, they detect the change in magnetic fields whilst passing over the ferrous trigger. This produces a digital signal from the open collector output. Differential probes allow for operation at larger air gaps and offer high immunity to noise. When connected to an interface unit or supporting ECU it is possible to determine rotational speed.

Output:Digital
Operating temperature:-10°C to +175°C
Range:15Hz to 20KHz
Air gap:1.5mm (typ) 2.5mm (Max)
Typical applications:Cam, Gearbox, Wheel speed