Forced Air
Another method to dry the generator is to run the set with no
excitation (see startup procedure item #2). The natural flow of
ambient air through the generator will tend to dry the
windings. This method can be accelerated by adding a source
of heat at the air intake to the generator. Heat at point of entry
should not exceed 80 C (180° F).
HYDRAULIC DRIVE GENERATORS,
SHAFT SPLINE LUBRICATION
The shaft spline should be greased prior to initial assembly to
the driver, and every three (3) months to reduce maintenance,
and prolong the life of the spline coupling per the following
procedure:
1. Material: Molybdenum Disulfide - sometimes referred to
as “Molly Grease.”
2. Turn the rotor assembly so that the Zerk fitting is in line
with the access hole in the top of the drive end bearing
bracket as illustrated in Figure 3.
3. Using a hand held grease gun with a solid coupling,
apply a small amount of grease into the fitting. DO NOT
OVER GREASE. Limit the amount of grease to one (1)
trigger pull of the grease gun.
Figure 3--Drive End Bearing Bracket
TESTING
Visual Inspection
Remove covers and look for any obvious problems: burnt
windings, loose connections, broken wires, frayed insulation,
cracked brackets, missing hardware, etc. Check for foreign
objects which may have been drawn into the generator. Verify
that the generator’s air gaps (main rotor and exciter) are free
from obstructions. If possible, rotate the generator manually
to ensure free rotation. Never “bar over” the engine generator
set using the generator fan.
THE FOLLOWING TEST MUST BE CONDUCTED BY
QUALIFIED ELECTRICAL PERSONNEL. LETHAL
VOLTAGE MAY BE PRESENT AT BOTH THE
GENERATOR AND VOLTAGE REGULATOR
TERMINALS DURING THIS PROCEDURE. CAUTION
MUST BE EXERCISED NOT TO COME INTO
PERSONAL CONTACT WITH LIVE TERMINALS,
LINKS, OR STUDS. SERIOUS INJURY OR DEATH
COULD RESULT.
CONSTANT EXCITATION TEST
(12V BATTERY TEST)
The generator “no load” voltage is dependent on exciter input
voltage and generator speed. With the generator operating at
rated speed and 12 volts dc applied to the exciter field, the
generators terminal voltage will be near rated value.
1. Shutdown the generator set and connect a voltmeter on
the generator terminals.
2. Disconnect the regulator’s F+ (F1) and F- (F2) leads and
connect them to a 12V battery. Caution should be taken
to ensure that the battery is not exposed to any
potential arcing.
3. With no load on the generator (main breaker open) run
the generator at rated speed. Measure the generator’s
terminal voltage and compare this value with values
recorded during installation.
If voltage readings are normal, the main generator and
excitation are operating properly. Troubleshooting should
continue with the regulator. If readings are not normal the
problem is in the generator. Continue testing diodes, surge
suppressor, and windings.
Continuity / Resistance Test
The generator has four components which can be checked
using an ohm meter: exciter stator, exciter rotor, main stator
and main rotor. Each of these components are comprised of
various windings which form a complete electrical path of
relatively low resistance. Using an ohm meter measure the
loop resistance of each component. Compare these
measured values with the values listed in the specification
section of this manual. Note that very small resistance values
require precision equipment to make accurate
measurements; however, a standard ohm meter will provide a
good indication of winding continuity.
12
Shaft Mounted
Zerk Fitting
Grease Gun
Access Hole
