Alternator: Description and Operation

Fig. 1 Delcotron Type 10 SI Alternator:

Fig. 2 Cross-Sectional View Of 12 SI Alternator:

Fig. 3 Delcotron Type 15 SI Alternator:

Fig. 4 Delcotron Type 17 SI Alternator:

Fig. 5 Delcotron Type 27 SI Alternator:

Fig. 6 Wiring Diagram Of Charging Circuit:

DESCRIPTION
These alternators (figures 1 through 5) feature a solid state regulator mounted inside the alternator slip ring end frame along with the brush holder assembly. All regulator components are enclosed in a solid mold with no need or provision for adjustment of the regulator voltage. The alternator bearings contain enough grease to eliminate periodic lubrication. Two brushes carry current through two slip rings to the field coil. The stator windings are assembled on the inside of a laminated core that forms part of the alternator frame. A rectifier bridge, containing six diodes and connected to the stator windings, changes A.C. voltage to D.C. voltage which is available at the "Bat" output terminal. Alternator field current is supplied through a diode trio connected to the stator windings. A capacitor, or condenser mounted to the end frame protects the diodes and rectifier bridge from high voltages and also suppresses radio noise. Some units incorporate a resistor in the warning indicator circuit (figure 6).

Some alternators used on diesel engines are equipped with an R terminal for the tachometer. On these units, if the alternator pulley is to be replaced, a pulley of the same diameter as the one removed must be installed, or tachometer may provide inaccurate readings. No maintenance or adjustments of any kind are required on this unit.