Page 34
In case of complete overhaul of genset, the bearing of the generator should be changed.
On request prelubricated bearings with regreasing system can be mounted. When regreasing use 20/ 30 grams of grease.
Following types of grease are to be recommended for nor- mal application:
MOBIL OIL: MOBILUX 3
SHELL: ALVANIA 3
AGIP: GR MW 3
ESSO: BEACON 3
9.3. VOLTAG REGULATOR
The generators are provided with automatic voltage regula- tor. The AVR is provided with potentiometers to adapt the characteristics of the AVR to different operating conditions.
The AVR is provided with adjustable stability circuitry to allow operations in a wide range of applications.
The AVR is equipped also with protecting circuit allowing the generator to operate underspeed if not loaded.
ATTENTIONI: it is not advisable to have the generator oper- ating loaded when the frequency (speed) is below the rated value: this kind of operation is an overload for the whole generator excitation system.
CONNECTION OF AVR
The AVR is connected to the terminals of the generator and to exciter
USE OF POTENTIOMETERS
P1/VOLT- Potentiometer for adjusting the output voltage of the generator; it allows a wide range of voltage setting (i.e. between 350 and 470 V; or between 170 and 260 V de- pending on winding connections)). When resetting the po- tentiometer, the voltage has to be set in the range
a finer regulation, or to adjust the voltage from control panel or to limit the voltage range, it is possible to insert an external potentiometer.
P2/FREQ- Potentiometer for changing the low speed protec- tion. Usually it is set in order to reduce the excitation when the speed is 10 % below the rated value at 50 Hz. By re- moving the bridge which is normally shorting the auxiliary terminals
P3/STAB- Potentiometer for stability adjust. By rotating it clockwise the stability of the regulator increases, but the response time becomes longer.
P4/AMP- Potentiometer for chancing the overexcitation limit device. The overexcitation limit device helps to protect the excitation system. This device is delayed to avoid transitory conditions (in case of overexcitation).
On the AVR there is a protecting fuse. ln case it should be necessary to replace it, high speed fuses should be used; in addition they should have high breaking resistance with a rated voltage of 50OV, and rated current of 1OA. The AVR is connected to the terminals of the generator and to exciter using
ARMTRONG POWER
SYSTEMS
Phone: (305) 470 0058
Fax: (305) 470 0068
Toll Free:
OWNERS MANUAL |
