ALTERNATORS
04
MAIN FEATURES
•
High specific output power, high
efficiency,
•
Designed for long life, maintenance free
operation under heavy duty conditions,
•
High operating reliability is assured by
optimizing the design for use in different
operating conditions,
MAIN FEATURES:
•
High resistance to salt spray, humidity,
water, mud, dust, vibrations, high
and low temperatures and other
environmental influences,
•
Designed to meet electromagnetic
compatibility and other international
directives and standards,
•
Produced using ecologically sound
technologies and environmentally
friendly materials,
•
Designed to meet a wide range
of engineering specifications and
applications.
Stator
The stator consists of 3-phase winding,
which is wound on to a laminated stator
pack. Electrical steel (cold rolled fully
processed - Dynamo) of 0.5mm thickness,
with controlled electrical and magnetic
characteristics, is used as standard for
alternators with higher performance
requirements, to decrease electric and
magnetic losses. Stators are specifically
designed to achieve a high winding fill
factor, to minimise electrical and magnetic
losses, to lower winding temperatures and
noise and to assure higher alternator output
characteristics.
MAIN SUBASSEMBLIES:
Alternators are air-cooled, 3-phase AC
synchronous generators with specific
claw-pole rotor design. The alternator
range includes 6-pole pairs (AAG, AAK, AAL,
AAN) and 8-pole pairs versions (AAT). The
rotor contains an excitation (field) winding
that is energized through slip rings and
brushes. An internal electronic voltage
regulator controls the amount of rotor field
current in order to maintain the alternator
output voltage within the required range.
A 3-phase full-wave rectifier bridge rectifies
the 3-phase AC voltage that is induced in
the stator windings. Power Zener diodes of
the press-fit type, which are built in rectifier
bridge, provide over-voltage protection.
Alternator cooling is provided by one
external (classic alternators) or two internal
fans (compact alternators). The negative
terminal is normally grounded. Insulated
ground versions, where the negative
terminal is connected directly to the battery,
are also available. Alternators are self-excited
through excitation diodes (D+, diode trio)
or directly from B+ terminal. Alternators
are mounted on the internal combustion
engine and driven by belt and pulley.
The alternator’s construction and approved
materials assure improved performance,
long life, and maintenance free operation.
Alternators are also designed to operate
under the harshest environmental
conditions: high and low temperatures,
salt spray, humidity, water, dust, vibrations,
aggressive liquids etc.
DESIGN
Rotor
The rotor excitation (field) winding fixed
between the claw poles provides excitation
of the alternator. The design of the rear part
of the alternator (rotor, rear bracket, rectifier,
regulator with brush holder) provides higher
protection for the slip rings and brushes
against environmental influences. Copper
or bronze (CuSn5) slip rings together with
metal-graphite brushes from established
suppliers, are designed to meet long life
requirements. The design of claw poles
ensures efficient magnetic excitation and
lower alternator noise.
Rectifier
The 3-phase full-wave rectifier bridge design
with press-fit type power Zener diodes,
ensures low temperatures at the rectifier
diodes, high resistance to vibrations and
over-voltage protection. Rectifiers are
mounted on the outer or inner side of the
rear end bracket, depending on the type of
the alternator. Flexible arrangement of all
types of terminals is ensured.