Basler SR4A, Инструкция по эксплуатации, Страница: 25 / 43

4-3
(1) Overvoltage (+20% or more) - If this condition occurs, open the shutdown switch
immediately and/or stop the prime mover. Determine the cause of overvoltage. If
necessary, refer to the troubleshooting chart.
(2) No voltage build Up
- If this condition exists, field flashing may be required, refer to para-
graph 4-7.
(3) Undervoltage (-15% or more) - If this condition exists, stop the prime mover and deter-
mine the cause of undervoltage. If necessary, refer to the troubleshooting chart.
(4) Voltage Builds Up and Collapses - If this condition exists, stop the prime mover and
determine the cause of collapse. If necessary, refer to the troubleshooting chart.
(5) Oscillating Voltage (Hunting) - If this condition exists, refer to the troubleshooting proce-
dures. (Voltage hunting can be caused by an unstable prime mover.)
c. If the voltage is unstable, perform the following steps:
(1) Loosen the locking nut on R4.
(2) Rotate R4 clockwise (CW) approximately 30
°
beyond the point that stable operation is
obtained. (If stability cannot be obtained by performing these steps, see paragraph 3-
2c.)
(3) Tighten lock nut on R4.
d. To adjust the voltage range for ±10%, verify R1 is adjusted to the center of its travel and
perform the following steps:
(1) Loosen the locking nut on R3 and adjust to obtain the rated generator voltage.
(2) Tighten lock nut on R3.
e. The voltage regulator is now ready for load test.
f. Apply load to generator.
g. Verify the voltage regulation is within ±1/2%. If it is not within these limits, refer to the
troubleshooting chart.
h. Alternately remove and apply load to determine if the generator voltage is stable.
i. If the generator voltage becomes unstable, adjust R4 for stable operation. When stability
cannot be obtained by performing these steps, refer to the troubleshooting chart.
B.
Instability
. Instability may occur when the no load field requirements of the exciter or generator
is near the minimum working voltage of the regulator. Increased stability may be obtained by adding
a resistor in series with the field. (See paragraph 3-2c.)
NOTE
Unstable governors are frequently the cause of generator voltage instability.
If a stability problem still exists after performing the procedure in paragraph
4-6a., steps f and g, a thorough check of the governor should be made.