Abstract :
A constant-speed dynamo for automobile lighting and for battery charging is to be preferred to other designs chiefly because it has the correct characteristics for its assigned work, because its efficiency is high while the wear is small, and because it is able to maintain a potential at the lamps so constant that it will even carry the lamps with the battery disconnected without injuring them. The generator and starting motor should be built as separate electric units because of the lighter, smaller, less complicated battery required, because of the greater reliability of the separate units, and because the characteristics of the starting motor (necessarily series-wound) are directly opposite to those of the generator (which is of necessity either shunt or compound-wound).
