Generac Power Systems 53187 - Manual (Page 15)

PARTI
THE REVOLVING FIELD AC GENERATOR
1
SECTION 1.3- MAJOR COMPONENTS
(UNITS WITH 15 INCH STATOR)
Components In Generator Control Panel (Continued)
AC VOLTAGE REGULATOR:
The Voltage Regulator is pow ered by stator excitation
w inding AC output. Approxim ately 4 to 8 volts is required
from that pow er source to turn the regulator on.
The Regulator is equipped w ith three (3) lam ps
(LED’s or "light em itting diodes). See Figure 5. These
lam ps are norm ally on during operation w ith no faults in
the system . The green EXCITATION lam p and the red
REGULATOR lam p are both turned on by stator excita­
tion w inding output. If, for any reason, stator excitation
w inding output w ere to be reduced, the tw o lam ps w ould
begin to dim . Finally, at som e m id-point voltage and
current, the tw o lam ps w ill no longer glow visibly.
The yellow SENSING lam p Is pow ered by sensing
input to the Regulator from the stator AC pow er w ind­
ings. The brightness of this lam p (LED) w ill depend on
available sensing voltage.
NO TE: Sensing input to the Regulator Is actually taken
from Hne-to-neutra! stator leads and Is about 120 volts
AC. How ever, this voltage Is boosted to about 240 volts
AC by the action of a sensing transform er.
The follow ing facts apply to Voltage Regulator opera­
tion:
1. The Regulator w ill shut dow n on occurence of one or
m ore of the follow ing conditions:
a. Loss of sensing voltage.
b. Loss of stator excitation voltage Input to the
Regulator.
c. Loss of circuit reference.
NO TE: The term "circuit reference" refers to voltage
regulator settings. The Regulator "regulates" excitation
w inding current flow to the Rotor w indings in order to
m aintain a sensing (actual) voltage that Is com m en­
surate w ith a preset "reference" voltage. T he reference
voltage is adjustable w ithin a 20 percent range at the
Regulator. Voltage regulation Is accom plished by
electronically m aintaining an ACTUAL voltage that Is
very close to the Regulator's preset REFERENCE volt­
age.
2. During generator operation, all three Regulator lam ps
should be ON.
a. REGULATOR lam p ON Indicates the Regulator is
functioning norm ally.
b. SENSING lam p ON indicates that norm al sensing
voltage Is available to the Regulator.
c. EXCITATION lam p ON Indicates that unregulated
excitation w inding output Is available to the
Regulator.
3. If the red REGULATOR lam p is OUT, a Voltage
Regulator fault exists or the Regulator has shut dow n
due to occurence of one or m ore Regulator shutdow n
conditions. See Step 1 above for conditions that w ill
result in Regulator shutdow n.
a. Expect to see a generator AC output voltage that
is com m ensurate w ith the Rotor’s residual m ag­
netism .
b. Rotor residual m agnetism w ill supply approxim ate­
ly 2 to 7 percent of the unit’s rated voltage.
NO TE: "Residual" m agnetism Is that m agnetism that Is
norm ally alw ays present In the Rotor. The Rotor m ay be
considered a "perm anent m agnet".
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