Generac Power Systems 53187 - Manual (Page 16)

SECTION 1.3- MAJOR COMPONENTS
(UNITS WITH 15 INCH STATOR)
1
PART 1
THE REVOLVING FIELD AC GENERATOR
Components In Generator Control Panel (Continued)
AC VOLTAGE REGULATOR (CONT’D):
4. If the green EXCITATION lam p goes out, loss of
stator excitation w inding output to the Regulator has
occured.
a. Loss of excitation w inding output w ill result in
Regulator shutdow n. The red REGULATOR lam p w ill
then go out, as w ell.
b. Under this condition, look for a generator AC output
voltage that is com m ensurate w ith residual Rotor
m agnetism (about 2-7% of rated volts).
c. W hen the REGULATOR and EXCITATION lam ps
are both out, the excitation circuit from the stator
excitation w indings to the voltage regulator Is suspect
(inclusive).
5. Should the yellow SENSING lam p go out, loss of
sensing voltage to the Regulator has occured.
a. Loss of sensing m ay cause the Regulator to shut
dow n. Both the SENSING lam p and the
REGULATOR lam p w ill then go out.
b. Generator AC output voltage w ill then be com m en­
surate w ith Rotor residual m agnetism (2-7% of rated
volts).
c. Look for a fault in the sensing circuit.
6. If all three lam ps go out, look for a fault that m ight
cause both sensing and excitation to fail.
a. Look for dirty or corroded slip rings, bad brushes,
defective Rotor.
b. Look for open circuit in W ires No. 1 and/or 4.
7. If the red REGULATOR lam p flashes, the
Regulator’s STABILITY potentiom eter requires ad­
justm ent.
SENSING TRANSFORMER:
The Part No. 67680 Voltage Regulator requires a
"line-to-line" sensing voltage (240 volts) for proper
operation. How ever, the sensing Is taken from "line-to-
neutral" W ires No. 11 and 22 (120 volts). For that
reason, the prim ary coil of a sensing transform er is
connected in series w ith the sensing leads. The sensing
transform er is a "step-up" type. That is, 120 volts AC in
its prim ary coil w ill induce 240 volts into its secondary
coil. It is the secondary coil voltage that is delivered to
the regulator as sensing voltage.
The sensing transform er is housed in the generator
control panel and is used on generator’s w ith the Part
No. 67680 Voltage Regulator and w ith 15 inch diam eter
stator lam inations.
The sensing transform er Is show n pictorially and
schem atically in Figure 6.
AC CIRCUIT BREAKER:
The AC circuit breaker protects the unit against cur­
rent overload by opening the AC output circuit in the
event the generator’s current (am perage) capacity is,/'”^
exceeded. The am perage at w hich the breaker w ill trip
(open) is the breaker’s trip rating.
The AC circuit breaker used on any specific generator
m odel w ill depend on the rated current (am perage)
capacity of that m odel.
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