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4.6.3
Diode protection
The rotating diodes bridge of the main exciter has an
varistor installed to protect against overvoltage and/or
voltage surge.
In case of failure of these components, they must be
replaced.
4.6.4
Protections on the voltage regulator
4.6.4.1
Protection against underfrequency
In order to put the alternator into operation, the
protection against underfrequency of the voltage
regulator must be set at 90% of the rated frequency (it
comes set from the factory) or the voltage regulator must
remain turned off until the group reaches the rated
speed, avoiding excitation overcurrents of the alternator.
NOTE
The other protections of the voltage regulator
are described in its specific manual.
Application 60HZ
(V)
Un
U/f
Application 50HZ
(V)
Un
U/f
4.7 VOLTAGE REGULATOR
The electronic voltage regulator is designed to keep the
voltage of the alternator constant regardless the load.
It may be assembled in the terminal box of the alternator
or on the control panel.
ATTENTION
Check, in the Manual of the voltage
regulator, the connecting terminals, the
wiring diagram and the setting parameters.
A wrong connection may cause the burning of
the regulator and/or the alternator windings.
Defects caused by this reason are not
covered by the warranty.
54
60
(Hz)
45
50
(Hz)
For further technical details on operation, functions,
connections, settings, anomalies, etc., refer to the
voltage regulator specific manual.
4.8 AUXILIARY EXCITER
WEG alternators GP_ model are manufactured with the
auxiliary exciter mounted in its back, which is responsible
for feeding the power circuit of the voltage regulator and
keeping the power supply of the voltage regulator, even
in case of short circuit on bus.
NOTE
Because the alternator maintains high SCC,
an overcurrent relay must be installed to
open the main breaker in no more than 20 s,
under penalty of burning the alternator.
4.9 ELECTRICAL ASPECTS
4.9.1
Electrical connections
The alternator electrical connections are responsibility of
the end user and must be carried out by qualified people.
The connection diagrams are provided along with the
technical documentation of the alternator.
4.9.1.1
Main connection
The main cable connections must be done observing the
tightening torque according to Table 4.7 for fixing the
cables.
Table 4.7: Tightening torque of the terminal screws for fixing the main
Thread Diameter
M5
M8
M10
M12
M16
Make sure the section and insulation of the
connecting cables are suitable for the alternator
current and voltage;
Before making the electrical connections between
the alternator and the load or power line, it is
necessary to check carefully the winding insulation
resistance, according to Table 4.2.
4.9.1.2
Grounding
The alternators must always be grounded with a cable of
proper section by using the terminal located in one of its
feet.
4.9.1.3
Electronic voltage regulator
The electronic voltage regulator must be correctly
adjusted before operating the alternator.
In order to change the connections or settings, refer to
the voltage regulator manual.
Installation, operation and maintenance manual
www.weg.net
cables
Tightening torque
(Nm)
5-6
20-25
39-49
64-84
165-206
|
23
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