Fig. 231.-Wiring Diagram Showing All Connections of Bosch Sta

WHEEL
GEAR

tery from discharging into the generator when the engine is at a standstill or whenever the terminal voltage of the generator is less than that of the battery. To attain this object a cut-out relay is inserted in the charging circuit and is equipped with a compound shunt and series winding. As the generator voltage builds up, the current through the shunt winding closes the cutout and permits the generator to charge into the storage battery. When the generator voltage falls below that of a storage battery the battery current passing through the series field winding of the cutout automatically demagnetizes the core and the circuit leading to the generator is opened, this preventing discharge of the battery. The cutout and regulator serves the double purpose of a cutout relay and regulation independent of belt tension. It is essentially two distinct relays, one serving to regulate the amount of charge from the generator to the storage battery regardless of belt tension. To accomplish this last step the shunt field of the generator is brought into the regulator at the terminal marked "F. L. D." by means

B

of vibrating contacts and additional resistance is automatically cut in the dynamo field when the voltage rises and cut out when the dynamo voltage lowers. In this manner the dynamo is made to hold to a practically constant current output which means a constant charge into the battery. It must be understood, however, that the belt tension must be sufficient to give the generator proper speed for producing a charging current, as the regulator