ENGLISH
23
EARTHING
POSITION
6.4 Preliminary Controls
6.4.1 Control of electrical insulation
Before starting up the electricity generating set or after long
shutdowns, check the insulation resistance of the windings
to earth.
CAUTION!
Disconnect the AVR (voltage regulator)
before carrying out this test.
The results must be over 2MOhm. If this is not the case, the
alternator alone should be oven dried at 80 - 100°C for 4
hours. Before carrying out this operation remove the voltage
regulator.
i
IMPORTANT!
The windings are tested under high voltage
during production. Additional high-voltage
tests can weaken the insulation thereby
reducing the working lifespan. If a high-
voltage test should prove necessary for customer
approval, these tests should be carried out at lower
voltages.
6.4.2 Direction of rotation
The generator is supplied with clockwise rotation, viewed
from the coupling side (unless otherwise specifi ed on order)
to produce a U-V-W phase sequence (according to IEC
60034-8). If rotation has to be reversed after delivery ask the
Sincro Technical Offi ce
for the relevant wiring diagrams.
The single bearing generators mount a fan unidirectional; dual
bearing generators mount a radial fan blade bidirectional.
6.2.2 Dismantling format SAE
For dismantling follow in reverse the instructions given at
section 6.2.1.
!
WARNING!
Be sure that the transit bar that holds rotor
in position is placed before any transport of
the generator.
6.2.3 Tightening torques
For mechanical connections it is recommended to use
screws at least class 8.8
The tightening torques are shown in the following table:
TIGHTENING TORQUES
(Nm
(Nm mat.
mat.
8.8)
8.8)
Dhread
diameter
Electrical
connections
Mechanical
connections
M5
3
6
M6
5
9
M8
10
23
M10
14
45
M12
20
80
M16
40
200
6.3 Earthing
The generator housing has to be connected to earth on
the base of the generating set. If fl exible antivibration are
mounted between the generator housing and its base, an
earth conductor should be connected in parallel through the
fl exible support and be adequately sized (usually half the
section of the main line cables).
By the feet on the housing there is an M12 threaded hole to
simply earthing of the housing (see fi gure).
!
WARNING!
Make sure the earthing procedure is carried
out properly.
