Soga sincro FB4 BT, Use And Maintenance Manual

Page: 19 / 36

FB BT - Giugno 2009 - Rev. 00 - 19
4. OPERATING PRINCIPLE AND CHARACTERISTICS OF THE VOLT-
AGE AND CURRENT REGULATOR SYSTEM
The exciter stator has a residual magnetism, which guarantees self-
exciting of the generator on start-up.
The
AVR , powered by an auxiliary circuit on the main stator, acts on
the exciter stator indirectly controlling the fi eld generated by the main
rotor by means of the sequence exciter rotor - diode bridge - main rotor.
The voltage regulator controls and keeps constant the output voltage of
three-phase bridge rectifi er.
For avoid to damage the battery during the charge cycle a current
control progressively reduced the voltage when the current overtakes
a preset value.
A frequency control progressively deactivates the machine when the
engine speed drops below a pre-set, adjustable threshold preventing
over-excitement at low operating speeds and abating the load engage
effects on the engine.
5. GENERAL MECHANICAL AND ELECTRICAL SPECIFICATIONS
FOR COUPLING WITH ENGINE
As an independent unit, designed to be built into a electricity generating
set, it is impossible to apply all the signal decals on the generator during
production. These decals, indicating a potential hazard or risk due to live
components are supplied loose and have to be applied by the constructor
of the electricity generating set in the positions indicated in the fi gure to
the side once assembly of the whole set has been completed.
The generators in the
FB range are designed to operate at a maximum
tem per a ture of 40°C and at a maximum altitude above sea level of
1000m at s.l.
The nominal performance indicated on the plate refers to operation within
these temperature and altitude limits.
At temperatures over 40°C and/or altitudes above 1000m at s.l. a loss
of performance should be expected (see table on the left).
The
Sincro Technical Offi ce should be advised of any environmental
con di tions that worsen the above limits.
The generators are fi tted with an air ventilation system, protective guards
and drip-proof covers; they are not suitable for outdoor installation un-
less an adequate protective shelter is provided. When under storage,
awaiting installation or in standby, it is advisable to use anticondensate
heaters to protect the windings from damp.
In the event of installation inside a closed housing, make sure that the cooling
air temperature for the generator does not rise above standard.
The housing must be constructed so that the engine air vent in the housing
is separate from the generator air vent especially if the air inlet in the hous-
ing has to be supplied by the cooling fan. What’s more, the generator air
vent should be constructed to prevent damp from entering by fi tting suit a ble
protections. The housing should be designed so that there is a minimum
clearance of 50mm between the generator air vent and any fl at surface.
If specifi ed on order, the generator can be fi tted with air fi lters.
Important! A drop in cooling air fl ow or inadequate protection of the
gen er a tor can lead to damage and/or malfunction of the windings.
The engine induces quite complex vibrations, including overtones that,
when added to the generator vibrations, can cause substantial vibration
levels damaging for the electricity generating set operation. Therefore
it is es sen tial that the plant engineer takes all necessary measures to
ensure align ment and provide a fi rm base and supports in order to pre-
ENGLISH
Ambient temp. (°C) 40 45 50 55 - -
1 0,96 0,82 0,88 - -
Altitude (m) 1000 1500 2000 2500 3000 -
1 0,96 0,93 0,90 0,86 -
Power factor 1 0,8 0,7 0,6 0,5 -
1 1 0,93 0,88 0,84 -
Important!
A drop in cooling air fl ow or inadequate
protection of the gen er a tor can lead to
damage and/or malfunction of the wind-
ings.