Voltage Regulator "Mark V; Voltage Regulator "Mark I - MarelliGenerators MJB 160 Instrucciones Y Advertencias De Seguridad

6. VOLTAGE REGULATOR "MARK V" ( M16FA655A )
The generators are provided with automatic voltage
regulator (AVR) MARK V.
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.
ATTENTION!: it is not advisable to have the generator operating 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 FAST-ON terminals.
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 depending on winding connections)). When resetting the potentiometer, the voltage has to
be set in the range +5%,-5% around the rated voltage of the machine. In order to obtain 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.
⇒ increase voltage
P2/FREQ- Potentiometer for changing the low speed protection. Usually it is set in order to reduce the excitation when the speed
is 10 % below the rated value at 50 Hz. By removing the bridge which is normally shorting the auxilary terminals 60-Hz of the
regulator, the low speed protection acts properly for 60 Hz.
⇒ increase frequency of intervention
P3/STAB- Potentiometer for stability adjust. By rotating it clockwise the stability of the regulator increases,but the response time
becomes longer.
⇒ increase response time, increase stability
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).
⇒ increase response time, increase stability
In the workshop the potentiometer is set in the way the said limitation comes into operation only under extreme
overexcitation.
Radio interference suppressor
The voltage regulator is internally provided with radio interference suppressor, in order to limit the radio interference from the
generators MJB among levels stated by C.E. standards for industrial areas.
Fuse
On the AVR there is a protecting fuse. Should it be necessary to replace it, high speed fuses should be used; in addition they should
have high breaking resistance with a rated voltage of 500 V, and rated current of 5A.
6.1 Voltage regulator "MARK I" ( M40FA640A/A )
The instructions contained in the paragraph are refereed to the synchronous generators MJB supplied from the automatic voltage
regulator (AVR) type "MARK I" (M40FA640A/A) rather than the regulator "MARK V" (M16FA655A). The voltage regulator MARK I is
supplied ready for use with generators in parallel, functionality with the mains in parallel and when a three-phase reference when
required.
The AVR is provided with potentiometers to adapt the characteristics of the AVR to the 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.
ATTENTION!: it is not advisable to have the generator operating loaded when the frequency (speed) is below the rated
value: this kind of operation is an overload for the whole excitation system of the generator.
SIN.UM.017.11
P1 VOLT
P2 FREQ
P3 STAB
P4 AMP
P
Q
Hz
60
⇒ decrease voltage
⇒ decrease frequency of intervention
⇒ decrease response time, decrease stability
⇒ decrease response time, decrease stability
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ENGLISH
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