TIGOR EV_ZIPTRON_SERVICE MANUAL

BRAKES 22 10.3. WHEEL SPEED SENSOR: (MONITORS WHEEL SPEED) Working principle: It is an active wheel speed sensor, which means that it must be connected to a voltage source for operation. It supplies a signal with constant amplitude pulses whose frequency varies with the wheel speed. It uses Hall Effect principle, it has a semiconductor chip with the electronic circuitry for supply and signal processing integrated on it. This chip is located within a completely insulated magnetic circuit consisting of permanent mag- net and pole elements. The wheel speed sensor is mounted directly above the magnetized toner wheel The magnetized toner wheel is a ring with teeth on it. The toner wheel is fitted on to the wheel hub. The alternating teeth and gap that accompanies the wheel rotation induces differential magnetic flux density, thus leading to the variation in the voltage induced in the semiconductor chip. The signal conditioning circuit converts this voltage variation into constant amplitude current pulses. The frequency of these pulses de- pends up on the wheel speed. This measurement principle permits zero speed measurement. Precise alignment and gap (1 mm) between the stator pole and the Toner wheel is vital. To obtain correct signal, the specified gap between the end of sensor & the toner ring must be maintained. Front : 0.5 mm to 1.5 mm Rear : 0.1 mm to 1.4mm Precautions while handling wheel speed sensor 1. Storage temperature (- 40°C to + 115°C) should not be exceeded 2. Avoid free fall of the sensor 3. The sensor tip should not be scratched. 4. Sensor should not be exposed to strong magnetic field.