The battery-charging circuit consists of an alternator, regulator, battery, (storage Battery) and the wiring. The
battery-charging alternator (Fig. 1) is introduced into the electrical system to provide a source of electrical
current for maintaining the storage battery in a charged condition and to supply sufficient current to carry any
other electrical load requirements up to the rated capacity of the alternator.
The hinge-mounted alternating current self-rectifying alternator is belt driven. The alternator drive pulley is
keyed to a shaft which is coupled to the blower drive gear.
An adequate alternator drive ratio is necessary for an
engine equipped with extra electrical accessories and one
that has to operate for extended periods at idle speeds.
Diodes, built into the slip ring end frame, rectify the three
phase ac voltage to provide dc voltage at the battery
terminal of the alternator, thereby eliminating the need for
an external rectifier alternator is also available in various
sizes and types, depending upon the specific application.
The SI series alternators have replaced the DN series
alternator. With the new alternators, the need for a
separately mounted voltage regulator is eliminated.
converted to metric dimensions, such as
Also, hole sizes of some mounting parts
will be changed to accommodate the new
The output terminal
(BAT) thread will be changed from a 12-24
to a M16XI thread.
The Figure 1. Typical Hinge-Mounted
Alternator (In-Line 53)
The access hole permitting the external adjustment of the voltage regulator has been eliminated on current
alternators. To adjust the voltage setting on the current alternators, remove the rectifier end plate. The voltage
regulator circuit board. Refer to the pertinent Delco Service Bulletin for complete adjustment procedure.
Maintain the proper drive belt tension. Replace worn or frayed belts. Belts should be replaced as a
set when there is more than one belt on the generator or alternator drive.