- 23 -
– Leave enough space for operation, inspection and
maintenance (at least 1 meter at each side).
– Check that the inner earthing system is in
compliance with the local legislation.
– Use coolant for the engine cooling system. Refer
to the Engine instruction book for the proper
coolant mixture.
– Check the tightness of the bolts and nuts.
– Check that the cable end of the earthing rod is
connected to the earth terminal.
3.3
Connecting the generator
set
3.3.1
Precautions for non-linear and
sensitive loads
The most common non-linear, 3-phase loads are
thyristor/rectifier-controlled loads, such as convertors
supplying voltage to variable speed motors,
uninterruptable power supplies and Telecom
supplies. Gas-discharge lighting arranged in single-
phase circuits generate high 3rd harmonics and risk
for excessive neutral current.
Loads most sensitive to voltage distortion include
incandescent lamps, discharge lamps, computers, X-
ray equipment, audio amplifiers and elevators.
Consult Atlas Copco for measures against the adverse
influence of non-linear loads.
3.3.2
Quality, minimum section and
maximum length of cables
The cable connected to the terminal board of the
generator set must be selected in accordance with
local legislation. The type of cable, its rated voltage
and current carrying capacity are determined by
installation conditions, stress and ambient
temperature. For flexible wiring, rubber-sheathed,
flexible core conductors of the type H07 RN-F
(Cenelec HD.22) or better must be used.
The following table indicates the maximum allowable
3-phase currents (in A), at an ambient temperature of
40°C, for cable types (multiple and single core PVC
insulated conductors and H07 RN-F multiple core
conductors) and wire sections as listed, in accordance
with VDE 0298 installation method C3. Local
regulations remain applicable if they are stricter than
those proposed below.
The generator set is wired for a TN-
system to IEC 364-3, i.e. one point in
the power source directly earthed -
in this case the neutral. The exposed
conductive parts of the electric
installation must be directly
connected to the functional earth.
If operating the generator set in
another power system, e.g. an IT-
system, other protective devices
required for these types must be
installed. In any case only a qualified
electrician is authorized to remove
the connection between the neutral
(N) and earth terminals in the
terminal box of the alternator.
!
Non-linear loads draw currents with
high contents in harmonics, causing
distortion in the wave form of the
voltage generated by the alternator.
!
Wire section
Max. current (A)
(mm²)
Multiple core Single core
H07 RN-F
2.5
22
25
21
4
30
33
28
6
38
42
36
10
53
57
50
16
71
76
67
25
94
101
88
35
114
123
110
50
138
155
138
70
176
191
170
95
212
228
205
