Pick-Up Coil: Description and Operation

Distributor:

The pick-up consists of a winding around a pole-piece attached to a permanent magnet.

During normal service, the air gap between reluctor and pick-up does not change and would only require resetting if it has been tampered with. If it is necessary to adjust the gap, it should be set to:

0.006 in (0.15 mm) to 0.014 in (0.35 mm)

The air gap is measured between a tooth on the reluctor and the pick-up module. The gap should be checked with a plastic feeler gauge. The use of a metal gauge may result in in an incorrect reading due to the components magnetic properties.

When the reluctor tooth passes across the pick-up limb, the magnetic field around the pick-up winding is intensified, creating a voltage in the winding. The rise and fall of this boltage is sensed by the amplifier and is used to trigger the output stage of the amplifier, which in turn switches on and off the current flowing in the primary winding of the coil. The amplifier controls the maximum current flowing in the primary circuit.