Section 3. Adjustment/Test; General; Generator Set Test; Pre-Operation Test Procedures - Hobart 6921 Series Operation And Maintenance Manual

OM-2040 / Operation and Maintenance Manual
90D20 / Generator Sets

Section 3. Adjustment/Test

1. General

These adjustment and test procedures are applicable to testing and adjusting the generator set after
major repair, major parts replacement, or overhaul.

2. Generator Set Test

a. Pre-operation Test Procedures
(1) Connect cables from the generator output terminals to a load bank. Use cables of the same
size and length as those to be used in service. Be sure the generator output "N" cable is
grounded.
(2) Check engine oil level. Oil should be at FULL mark on gage rod.
(3) Check tension of fan and generator V-belts. (See Section 2-1, Figure 5 and 6) .
(4) If governor throttle linkage was changed, check all linkage to make certain engine speed may be
controlled when started. See Figure 15.
(5) Inspect for oil and fuel leaks.
(6) If the setting of the voltage regulator rheostat (37, Fig. 1) has been changed, set at CENTER
position (halfway between full clockwise position and full counterclockwise position.)
(7) Check engine circuit fuse (41, Fig. 1) by placing panel light switch (31) in ON position. If panel
lights (2) operate, the fuse (41) switch (31) and lamps are good.
(8) Check fault indicating lights (10) by pressing test switch (8) . If lights glow, fuse (41) and
indicating lamps are good.
(9) Make a general inspection of all wiring, and terminals. Inspect the equipment to be certain no
damage will result from starting the engine.
(10) At initial start-up after generator overhaul or repair, "flash" the exciter field momentarily with 12-V
DC to the field windings as follows:
CAUTION
a. Flashing exciter field using test box.
• If a test box (see Sect. 1-3, Fig. 3) is available, connect it to receptacle connector (Sect.
1-3, Fig. 4).
(aa) Rotate the selector knob (Sect. 1-3, Fig. 3, Item 1) to position 8.
(bb) Use two jumper leads, each equipped with an alligator clip and a test prod, to connect
12 V DC power to test jacks (2 and 3) on the box. Connect positive jumper from input
terminal on starter solenoid (2, Fig. 2) to red test jack. Connect negative lead from starter
ground terminal (3, Fig. 2) to black test jack.
(cc) Momentarily pressing pushbutton switch (Sect. 1-3, Fig. 3, item 2) will flash the exciter
field.
(dd) Disconnect jumper leads.
February 28/94 Revised
Engine must not be running when field flashing to prevent voltage regulator
damage.
Chapter 2-3
Page 1