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Introduction

The demands made on the vehicle's power supply are increasing steadily. For instance, the required generator/alternator power outputs increased about 5-fold between 1950 and 1980. In the meantime the amount of power needed in the vehicle has more than doubled again. In the coming years, the need for electrical energy in the vehicle will rise at an ever faster pace. The increasing demand for electrical energy stems from the large amount of electrical equipment which has become an integral part of every modern-day vehicle. This stems from the ECUs for electronic systems, and from all the safety, comfort and convenience electronics and their components.

The generator (more correctly termed the ?alternator?) is the vehicle's electricity generating plant. On the one hand, the increasing number of electrical loads demands higher alternator outputs. On the other hand, considering the restricted installation space under the hood, the equipment providing this power should under no circumstances become larger and heavier in the process. Bosch therefore has developed alternators which not only comply with these demands, but which at the same time are quieter, more long-lived, and able to withstand higher loading than their predecessors.Wear-free electronic voltage regulators are a prerequisite for coping with the extensive engine-speed changes and fluctuations in loading which are characteristic for vehicle operations. Extremely lightweight and requiring a minimum of space, these regulators maintain the alternator voltage output constant across the engine's complete speed range.

The starter motor must at all times be ready to crank the engine, and during the course of its life must successfully complete thousands of starting operations. Taking a passenger car which is mainly operated in town traffic, this can equate to about 2000 engine starts per year for an average annual mileage of 15,000 km (10,000 miles).As with its alternators, Bosch was successful in increasing starter-motor output while at the same time making the unit lighter and smaller. The application of reduction-gearing in combination with permanent-magnet techniques was decisive here.All Bosch starters are highly reliable while ensuring maximum operational dependability.

Although the individual components ?Alternator with voltage regulator? and ?Starter motor? are subject to their own operating conditions, they are highly dependent on each other. For this reason, development activities are concentrating on their effective interplay. This manual from the Bosch ?Yellow Jacket? series deals with the design and construction of the most important components, as well as with their essential characteristics and differences and their importance in the vehicle's electrical system.

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