Initial Start-Up; Aftersales Assistance And Maintenance; Control And Check Procedures; Control Of Windings And Electrical Insulation - Sincro SK225 Serie Manual De Uso

6.4.7 Initial start-up

Before starting up the generating set check that all ex-
ternal connections are in order and that the protections
are in place.
During the initial start-up pay particular attention for any
unusual noise that might signal an incorrect alignment
between engine and generator.
Do not touch the generator while in operation
and immediately after the generating set has
stopped, since certain parts may still be very
WARNING! hot.
Generators are rotating electrical machines that involve
potentially hazardous live or moving parts, therefore the
following is strictly prohibited:
• an improper use;
• removal of covers and disconnection of safeties.
Due to these inherent hazards, all works of electrical
or mechanical nature must be carried out by qualified
specialists.
7. AFTERSALES ASSISTANCE AND
MAINTENANCE
The maintenance and fault diagnostic
procedures involve risks that may cause
severe injury or even death. These
WARNING!
procedures should therefore be carried out
solely by qualified electrical and mechanical
specialists. Before any maintenance and
cleaning work make sure that there are no live
parts, that the generator housing has cooled
to ambient temperature, that the generating
set cannot be accidentally started up and
that all procedures are strictly observed.
The lack of routine check-ups and poor
maintenance can cause severe damage to
persons and/or objects.
WARNING!

7.1 Control and check procedures

7.1.1 Control of windings and electrical insulation

The condition of the windings can be checked by
measuring their insulation resistance. While running
this test disconnect the voltage regulator and EMC filter.
It is usually sufficient to control the main winding.
The readings should give a measurement of at least
2 MOhm. If the insulation resistance is below this
threshold, the alternator alone should be oven dried
at 80 ÷ 100°C for 6 hours. Before carrying out this
operation remove the voltage regulator.
SK225

7.1.2 Control of the rotating rectifier diodes

This check can be performed with a multimeter, the
knob must be selected to the position "Diode test".
The lead of each diode has to be removed from the
connections with the rotor exciter (see figure), but it's
not necessary to removed them from the alluminium
plate where they are fixed.
The faulty diode will have high (theoretically infinite)
resistance in both directions (open diode) or it can
have low resistance on both directions (diode in short)
by placing the tips on both directions. Meanwhile
the correct working diode will have low resistance in
forward direction and high (theoretically infinite) in the
other (reverse) direction.

7.1.3 Control of bearings

During maintenance control the condition of the bearings
and check that no grease has leaked; the lifespan of the
bearings depends on the vibrations, loads they undergo
(vibrations can increase considerably with a bad
alignment) and on the working conditions. So check for
any unusual signs: vibrations, unusual noises, clogged
air vents.
If undue vibrations or noises appear after long-term
usage, these could be due to a worn bearing that, if
damaged, has to be replaced
The bearing should always be replaced after 20.000
working hours.
In case of regreaseable bearings, check the nameplate
for regreasing:
- greasing intervals,
- grease type and quantity.
A bearings lifespan is closely linked to the
working conditions and environment.
IMPORTANT!
Long periods of sustained vibrations can
damage the bearing balls and their seat.
Too high humidity can emulsify the grease
and encourage corrosion.
IMPORTANT!
Intense vibrations caused by the engine
bad alignment of the components in the
generating set put the bearing under
IMPORTANT! stresses that will reduce its lifespan.
SK250
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