Version 2.0
Activity: stability setting
procedure
Date (27/11/2014):
Author: Pierpaolo
Canale
Overseen by: Lino
Zerbato
Basic guideline of potentiometer stability setting on Mecc Alte
DSR_DER-1 digital regulators.
General introduction to the issue.
Alternator is part of a system that can be schematized as "alternator + engine".
The alternator alone, properly set up, does not have any instability problem, but when it is
running with an engine instability speed/voltage situations may happen.
There is a dedicated potentiometer on the AVR (STAB potentiometer) for the adjustment
of the stability. This is because the voltage regulation system of the alternator and the
speed regulation system of the engine could come into conflict, causing
possible oscillations both of the voltage and the speed.
If this happens, the problem can be solved by adjusting the STAB potentiometer of the
regulator of the alternator and/or the stability of the speed controller of the engine.
It is important to stress that Mecc Alte alternators are fully tested by using an electrical
motor, as prime driver, and not an engine.
So, the STAB adjustment performed is properly set up on an "alternator driven by an
electric motor".
Here are some very general instructions to follow in case of voltage instability problems of
"alternator+engine" system.
1) Check the setting of STAB potentiometer on AVR and make sure that it matches with
the setting reported in the tables below (pages 3, 4 and 5) for the machine under testing
at 50 Hz or 60 Hz, counting the tags clockwise.
2) If it does not match, reset STAB potentiometer on AVR according to what reported in
the tables below. In case of missing information, set STAB potentiometer in middle
position.
3) If after this operation (step 1 and 2) voltage instability problem still persists, turn STAB
potentiometer 1 tag anticlockwise and retest.
4) If nothing changes or in case of small improvement, turn STAB potentiometer 1 tag
more anticlockwise and retest.
Continue with this procedure (that is, turn STAB potentiometer 1 tag anticlockwise and
retest) till to solve voltage instability problem.
Be aware that below tag n. 2 stability is at its minimum value and therefore it does not
change anymore.
5) If turning STAB potentiometer anticlockwise, voltage instability problem increases, reset
STAB potentiometer on AVR according to what reported in the tables below (pages 3, 4
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Version 2.0
Activity: stability setting
procedure
Date (27/11/2014):
Author: Pierpaolo
Canale
Overseen by: Lino
Zerbato
and 5); in case of missing information, set STAB potentiometer in middle position. Then
turn STAB potentiometer 1 tag clockwise and retest.
6) If nothing changes or in case of small improvement, turn STAB potentiometer 1 tag
more clockwise and retest.
Continue with this procedure (that is, turn STAB potentiometer 1 tag clockwise and retest)
till to solve voltage instability problem.
Be aware that above tag n. 10 stability is at its maximum value and therefore it does not
change anymore.
7) If voltage instability problems of "alternator+engine" system have not been solved
following steps above from 1 to 6, it could be also necessary to readjust the stability
(gain) of the speed controller of the engine according to its manual. If also this does not
solve the problem, we advise to change some stability software parameters of DSR / DER1 (P[11], P[12] and P[13]) by following the manual AVR instructions.
For any further information and/or clarification you may need about this subject do not
hesitate to contact Mecc Alte.
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Version 2.0
Activity: stability setting
procedure
Date (27/11/2014):
Author: Pierpaolo
Canale
Overseen by: Lino
Zerbato
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Version 2.0
Activity: stability setting
procedure
Date (27/11/2014):
Author: Pierpaolo
Canale
Overseen by: Lino
Zerbato
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Version 2.0
Activity: stability setting
procedure
Date (27/11/2014):
Author: Pierpaolo
Canale
Overseen by: Lino
Zerbato
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