Lucas Industries Limited

Lucas Electrical Limited

Thomas Nicol

William F Hill

Maurice J Allport

David Wiley

A battery charging system includes an alternator with a rectifier connecting the alternator output to the battery. A voltage rectifier controls the current in the alternator field winding in accordance with the battery voltage. A transistor switch in the voltage regulator controls the bias current to the output stage of the regulator and is in turn controlled by a differential amplifier through a diode pump. The differential amplifier is connected to detect the presence of an a.c. on one phase of the alternator and causes the transistor to be switched off, disabling the output stage of the regulator, whenever no a.c. signal is present.

Battery charging systems for road vehicles

An automotive battery charging system includes a novel temperature compensation arrangement. The conventional input potential divider has a further resistor and a temperature compensation output transistor in series across one leg of the divider. The voltage at the base of the temperature compensation output transistor is controlled by a temperature sensing circuit so as to fall linearly with rising temperature. Resistors are adjusted in manufacture to give the required level and slope for the temperature compensation characteristic.

Automotive battery charging system

A liquid level detector circuit includes a capacitive probe, a reference capacitor and two further capacitors connected as a capacitor bridge, with one terminal of each of the probe and the reference capacitor earthed and a common terminal of the further capacitors providing an output to a warning circuit. An oscillator is provided by two transistors connected so as alternately to interconnect the other terminals of each of the probe and the reference capacitor and to connect these to two different fixed potentials. The further capacitors charge slowly but discharge rapidly so that when there is any imbalance there is an excursion of the mean voltage at the common terminal during discharge which, depending on the polarity of the excursion can trigger the warning circuit.

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Lichfield, United Kingdom

Thomas Nicol