The automobile owner's guide

by Frank B. Scholl

CHAPTER XXV
THE DELCO ELECTRICAL SYSTEM—BUICK CARS

The motor generator which is located on the right side of the engine is the principal part of the Delco System. This consists essentially of a dynamo with two field windings, and two windings on the armature with two commutators and corresponding sets of brushes, in order that the machine may work both as a starting motor, and as a generator for charging the battery and supplying the lights, horn and ignition. The ignition apparatus is incorporated in the forward end of the motor generator. This in no way affects the working of the generator, it being mounted in this manner simply as a convenient and accessible mounting. The motor generator has three distinct functions to perform which are as follows:

1.—Motoring the generator.

2.—Cranking the engine.

3.—Generating electrical energy.

Motoring the generator is accomplished when the ignition button on the switch is pulled out. This allows current to come from the storage battery through the ammeter on the combination switch, causing it to show a discharge. The first reading of the meter will be much more than the reading after the armature is turning freely. The current discharging through the ammeter during this operation is the current required to slowly revolve the armature and what is used for the ignition. The ignition current flows only when the contacts are closed, it being an intermittent current. The maximum ignition current is obtained when the circuit is first closed and the resistance unit on the front end of the coil is cold. The current at this time is approximately 6 amperes, but soon decreases to approximately 3¹⁄₂ amperes. Then as the engine is running it further decreases until at 1000 revolutions of the engine it is approximately 1 ampere.

LEAD TO SWITCH.
TO SHUNT FIELD.		IGNITION COIL.	RESISTANCE UNIT.
			TO THIRD BRUSH.
TO POS. BATTERY.	DIS. HEAD LOCATING TONGUE.
TO NO 1 TERMINAL.
TO NO 2 TERMINAL.
BRUSH OPERATING ROD.			OILER A.
TO STARTING PEDAL.
STARTING GEARS.
A		FIELD COIL.
OILER B.			DISTRIBUTOR SHAFT GEAR.
FLY WHEEL.			PUMP SHAFT.
		ARMATURE.
LUBRICATOR C.
GENERATOR CLUTCH.
ROLLER BEARING.		BALL BEARING.
OIL DRAIN.
ONE WAY CLUTCH BUILT IN THIS GEAR.		MOTOR COMMUTATOR.	GENERATOR COMMUTATOR.

Fig. 93. Delco Motor Generator—Showing Parts

This motoring of the generator is necessary in order that the starting gears may be brought into mesh, and should trouble be experienced in meshing these gears, do not try to force them, simply allow the starting pedal to come back giving the gears time to change their relative positions.