Electric Power Generation
Installation and maintenance
LSA 52.3 / LSA 53.2 / LSA 54.2
Industrial Range Alternators
__________________________________________________________________________________________________
6
b - Stator air exhaust (warmed air)
c – Rotating diodes air cooling
2.1.2 Excitation field winding
The excitation field winding comprises a wound solid
element.
The excitation is equipped with a flange at the rear bearing
of the machine.
2.1.3 Stator protection
2.1.3.1 Heating resistance
The heating element avoids internal condensation during
the shutdown periods. It is connected to the terminals of
the main terminal box. The resistance heater is switched
on as soon as the machine is shut down.
The electrical characteristics are provided in Section 1
"Technical Characteristics".
2.1.3.2 Stator winding temperature sensor
The temperature sensors are located in the zone assumed
to be the hottest part of the machine. The sensors are
connected to a terminal box.
Depending on the insulation class of the machine, the
temperature of the sensors must not exceed a maximum
of:
INSULATION CLASS ALARM TRIPPING
180 °C 185 °C
To improve the protection of the machine, we recommend
setting the alarm set-point according to the actual
conditions of the site obtained after a representative
operating time:
Alarm temperature (*) = Highest recorded temp + 10°K
Trip temperature (*) = Alarm temperature + 5 °K
(*) do not exceed the values of the previous table.
(*) Max. recommended temp: Maximum temperature
measured at the stator after a representative operating
time under severe operating conditions.
E.g. a class H insulation machine of 3000 kVA reached a
maximum of 110°C at the stator after a representative time
of operation at the site. Set the alarm temperature to 120°C
instead of 180°C indicated in the previous chart. Set the
trip setting to 125°C instead of the 185°C shown in the
previous table.
2.1.3.3 Stator air temperature probe
As an option an RTD or thermostat can measure the stator
air inlet temperature (cold air).
Stator air inlet temperature; Alarm points and shutdown:
• alarm Nominal air inlet stator + 5 K
• shutdown 80°C
Stator air outlet temperature; Alarm points and shutdown:
• alarm Nominal air inlet stator + 35K
• shutdown Nominal air inlet stator + 40K
NOTE:
For an open machine the nominal air temperature entering
the stator corresponds to the ambient temperature.
NOTE:
If quickly restarting after a shut-down, inhibit the stator air
sensor safety "alarm" for a few seconds (no more than 30
s) during the machine start up.
NOTE:
For a water cooled machine (CACW) the nominal air
entering the stator may be approximated as following:
Tair entering stator = Twater entering cooler + 15°K.
2.1.3.4 Bearing vibration sensor
This chapter concerns the adjustment of seismic sensors.
For more information on adjusting proximity sensors, see
Chapter 2.2.6.1.
The level of vibration of the machines depends directly on
the use made of them and on the characteristics of the site.
We propose the following adjustment:
Vibration Alarm (*) = Site Highest Vibration level + 50%
Vibration Trip = Vibration Alarm + 50%
(*) do not exceed the values of the following chart.
The machines are engineered to be able to withstand the
vibration level specified by the standard ISO8528-9 and
BS5000-3.
Maximum levels for: Internal combustion engines
alternating current motors
Nominal speed
(rpm)
kVA Generator vibration level
(nominal conditions)
Overall
(mm/s rms)
(2–1000 Hz)
Any harmonics
1300 to 2199 > 250 < 20
< 0.5 mm; pp
(5 – 8 Hz)
< 9 mm/s; rm
(8 – 200 Hz)
721 to 1299
≥ 250
< 20
>
1250
< 18
≤ 720 >
1250
< 15
< 10 (*)
(*) generator on concrete base
Maximum levels for: Turbines
Turbines
(hydraulics; gas; steam)
Max. recommended value:
4.5
(global; mm/s (rms)
To Next Page
Loading...
