Basler Electric AVC63-12 - Manual (Page 7)

Publication
9337200991
Revision
J
Instructions
Date
01/15
Page
7 of 10
ADJUSTMENTS
AVC63-12 and AVC125-10 adjustments are described in the following paragraphs.
Field Flashing
When the regulator is operated with the generator for the first time, the residual magnetism may not be of
sufficient magnitude or the correct polarity. If the generator residual voltage is less than 6 Vac for the AVC63-12
or 12 Vac for the AVC125-10 at terminals 26, 28 and/or 30, shut down the prime mover and proceed with the
following steps.
Caution
Do not flash the field when the generator is in motion. Regulator damage may
result.
1. With the prime mover at rest, apply an ungrounded dc source of not more than 24 Vdc to terminals F1 (+) and
F2 (–) in series with a limiting resistor. Use 1
 of resistance for each volt applied. The power source should
have a rating of at least 1 W/
.
EXAMPLE: If using a 24 Vdc source, use a 24
, 24 W resistor.
2. Allow the field to be flashed for approximately 10 seconds before removing the dc source.
3. If voltage buildup does not occur after performing steps 1 and 2, verify the polarity of the dc source and repeat
steps 1 and 2.
Frequency Rolloff (UF KNEE)
The underfrequency knee (rolloff) is typically set below the nominal system frequency. When the generator speed
falls below the knee setpoint of the regulator, generator voltage is reduced proportionally to the speed of the
machine. To adjust the underfrequency knee, perform the following steps.
1. Adjust the generator frequency at the nominal level (50, 60, or 400 Hz).
2. Adjust the UF KNEE control counter-clockwise.
3. Adjust the VLT ADJ control for nominal generator voltage.
4. Adjust the UF KNEE control clockwise until the voltage begins to decrease.
5. Adjust the UF KNEE counter-clockwise until the voltage just returns to the value set in step 3.
The underfrequency knee is now set just below the nominal operating frequency. Further rotation in the counter-
clockwise direction will lower the knee frequency setpoint at which underfrequency compensation just begins.
Connecting a jumper from terminal 8 to 6a will provide an underfrequency slope of 1 PU V/Hz. No connection to
terminal 8 will result in an underfrequency slope of 2 PU V/Hz. The slope can also be selected on the 400 Hz
models. However, the actual V/Hz curve is approximately 1 PU or 2 PU, depending if terminal 8 is jumpered to 6a.
Stability (STB)
An oscilloscope or other voltage recording device should be used in an optimal stability setting is desired. Adjust
the stability setting with the generator at no load.
Clockwise rotation of the STB control will slow response time. Counter-clockwise rotation will speed response
time. If rotated too far counter-clockwise, the generator voltage may oscillate (hunt).
To obtain good response, rotate the STB control counter-clockwise until the system just begins to oscillate. Then,
rotate the control clockwise just past the point where oscillation occurred. Apply various amounts of load to
determine proper stability performance.
Voltage (VLT ADJ)
Installation of a jumper across terminals 4 and 7 enables the front-panel VLT ADJ control to vary the generator
nominal voltage over the operating range.
To allow operation of an external voltage-adjust control, remove the jumper between terminals 4 and 7 and
connect a 10 k
, external potentiometer across terminals 6a and 7. The front-panel VLT ADJ control should be
set fully clockwise for proper operation of the external adjustment. Note that as the external potentiometer
resistance increases, generator voltage also increases.