Breather Assembly - Guardian 4700 Repair Manual

VOLTAGE
ADJUST POT
LED
Figure 2-7. – Voltage Regulator
The regulator mounts a "VOLTAGE ADJUST" poten-
tiometer, used for adjustment of the pre-set REFER-
ENCE voltage. A lamp (LED) will turn on to indicate
that SENSING voltage is available to the regulator
and the regulator is turned on.
The regulator mounts a "VOLTAGE ADJUST" poten-
tiometer, used for adjustment of the pre-set REFER-
ENCE voltage. A lamp (LED) will turn on to indicate
that SENSING voltage is available to the regulator
and that the regulator is turned on.
ADJUSTMENT PROCEDURE:
With the frequency set at 62.5 Hertz and no load on
the generator, slowly turn the voltage adjust pot on
the voltage regulator until 124 VAC is measured. If
voltage is not adjustable, proceed to Section 6 -
Troubleshooting; Problem 2.
NOTE: If, for any reason, sensing voltage to the
regulator is lost, the regulator will shut down and
excitation output to the Rotor will be lost. The AC
output voltage will then drop to a value that is
commensurate with Rotor residual magnetism
(about 7-12 VAC). Without this automatic shut-
down feature, loss of sensing (actual) voltage to
the regulator would result in a "full field" or "full
excitation" condition and an extremely high AC
output voltage.
NOTE: Adjustment of the regulator's "VOLTAGE
ADJUST" potentiometer must be done only when
the unit is running at its correct governed no-load
speed. Speed is correct when the unit's no-load
AC output frequency is about 62.5 Hertz. At the
stated frequency, AC output voltage should be
about 124 volts.
11S
22S
4 OK
6
2A
MAJOR GENERATOR COMPONENTS

BREATHER ASSEMBLY

DESCRIPTION:
A crankcase breather is located in the rocker arm
cover of horizontal crankshaft engines (Figure 2-8).
The breather serves to maintain a reduced pressure
in the engine crankcase, to prevent oil from being
forced past the oil seals, gaskets or piston rings.
The CHECK VALVE allows excess pressure to be
vented out of the crankcase and to atmosphere
through the BREATHER TUBE. Two small DRAIN
HOLES allow condensed oil vapors to return to the
crankcase.
CHECK
VALVE
DRAIN
HOLE
ROCKER
ARM
COVER
Figure 2-8. – Crankcase Breather
INSPECTION:
1. Remove the breather tube. Check tube for cracks, hardening or
other damage. Replace if necessary.
2. Clean the rocker arm cover in commercial solvent.
3. Make sure the two small drain holes are open. If necessary,
use a length of wire to open the holes.
4. Check the rivets that retain the check valve, make sure they
are tight.
5. The breather plate is retained in the rocker arm cover with a
continuous bead of Type 103 black RTV sealant. This sealant
must not leak. Test the sealant for leakage as follows:
a. Seal all holes on the breather plate.
b. Apply air pressure of 5 psi (0.352 kg/cm ) through the
breather hose hole. No leakage must be observed.
c. If necessary, reseal the plate with Type 103 black RTV
sealant.
Section 2
BREATHER
TUBE
Page 9