Generac Power Systems GP1800 Repair Manual page 21

GENERAL INFORMATION
windings and through the negative (-) slip ring and
TO LOAD
brush on Wire 0.
The greater the current flow through the rotor wind-
MLB = MAIN LINE
MLB
CIRCUIT BREAKER
ings, the more concentrated the lines of flux around
the rotor become. The more concentrated the lines
240 VAC
of flux around the rotor that cut across the stationary
120 VAC
stator windings, the greater the voltage that is induced
into the stator windings.
STATOR
Initially, the AC power winding voltage sensed by the
POWER
regulator is low. The regulator reacts by increasing
WINDING
the flow of excitation current to the rotor until volt-
age increases to a desired level. The regulator then
MAGNETIC
maintains the desired voltage. For example, if voltage
FIELD
exceeds the desired level, the regulator will decrease
the flow of excitation current. Conversely, if voltage
ENGINE -
drops below the desired level, the regulator responds
DIRECT ROTOR
by increasing the flow of excitation current. DRIVE
AC POWER WINDING OUTPUT:
MAGNETIC
FIELD
A regulated voltage is induced into the stator AC
power windings. When electrical loads are connected
STATOR
across the AC power windings to complete the circuit,
EXCITATION
current can flow in the circuit.
WINDING
CAPACITOR
A
CAPACITIVE DISCHARGE
4 (+) RED
0 (-) WHITE
VOLTAGE REGULATOR
C
PART 1
120 VAC
STATOR
POWER
WINDING
C1 FEMALE
Figure 3. Alternator Configuration C
BRUSHED EXCITATION SYSTEM
MLB = MAIN LINE
CIRCUIT BREAKER
120 VAC
STATOR
POWER
WINDING
ENGINE -
DIRECT
DRIVE
EXCITATION
Figure 2. 240 VAC Sensing Alternator
B
DIRECT EXCITATION
S15
WHITE
AVR SENSING
S16
GREEN
NOT USED
C1 MALE
RED (R2 – 11)
BLUE (R1 – 22)
BROWN (L2 – 33)
WHITE (L1 – 44)
Section 1.4
TO LOAD
MLB
240 VAC
120 VAC
SENSING
STATOR
POWER
WINDING
MAGNETIC
FIELD
- +
ROTOR
MAGNETIC
FIELD
AUTOMATIC
STATOR
VOLTAGE
REGULATOR
WINDING
2
BLUE
DPE
6
BLUE
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