Generac 86640 - Manual (Page 6)

A More Sophisticated Generator
Figure 4 Is a diagram of a more sophisticated generator.
A regulated direct current (DC) is delivered to the rotating
magnet (Rotor), via CARBON BRUSHES and SUP RINGS.
This creates a regulated magnetic field around the Rotor
which cuts across the stationary Stator windings to Induce a
regulated voltage into those windings. When the Stator circuit
is corfipleted by connecting a load, current will flow through
the Stator windings to the load.
A Typical AC Generator
Rgure 5, below, Is an operating diagram of a typical AC
generator. Operation of this typical generator may be briefly
described as follows:
D
The ROTOR is attached to the engine’s power takeoff
(PTO) shaft and turns at the same speed as the engine.
D
As the ROTOR turns, its magnetic field cuts across the
stationary coils of a STATOR EXCITATION WINDING
and dual STATOR AC POWER WINDINGS. A voltage is
induced into these stationary widings.
□ Unregulated alternating current (AC) is delivered from
the STATOR EXCITATION WINDING to the VOLTAGE
REGULATOR, via an EXCITATION CIRCUIT
BREAKER.
n "Sensing" leads deliver a signal of ACTUAL AC POWER
WINDING voltage to the VOLTAGE REGULATOR.
n The VOLTAGE REGULATOR electronically compares
the ACTUAL AC POWER WINDING voltage to a preset
REFERENCE VOLTAGE and changes №e STATOR
EXCITATION WINDING output to direct current (DC).
□ If ACTUAL POWER WINDING voltage Is less than the
REGULATOR’S preset REFERENCE voltage, REGU­
LATOR action will increase direct current flow to the
ROTOR windings. The ROTOR magnetic field strength
will then increase and the voltage induced into the STA­
TOR AC POWER WINDINGS will then increase.
□ When ACTUAL POWER WINDING voltage is greater
than the REGULATOR’S preset REFERENCE voltage,
direct current flow to the ROTOR will be decreased by
REGULATOR action to reduce ROTOR magnetic field
strength.
Rgure 5. Operating Diagram of a Typical AC Generator
12
-S-
11
4^
ITEM DESCRIPTION
i RÓTOF1
2 STATOR POWER WINDING
3 STATOR EXCITATION WINDING
4 FIELD BOOST
5 ENGINE
6 BRUSHES
7 SLIP RINGS
8 VOLTAGE REGULATOR
9 SENSING LEADS
10 THERMAL PROTECTOR
11 THERMAL PROTECTOR BYPASS
12 EXCITATION CIRCUIT BREAKER
13 ELECTRICAL LOAD
14 MAGNETIC FIELD
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