When VR101 R14 and R1 are both correctly adjusted, a small change in R1 will turn the light bulb on and off.
If slight remains "full on", or does not come on at all, the voltage regulator is defective.
R11 stability adjustment affects speed at which light goes on and off. Normal setting, which assures good
stability, is in the almost fully clockwise position. This setting tends to slow up generator response time,
hence, rotating counterclockwise speeds up system response time. However, when set too far
counterclockwise, the generator voltage tends to oscillate (hunt). Final setting of VR1O1 R1 should be well
above the point where oscillation occurs in that system voltage stability is most critical in no load condition.
Reset VRiO1 rc to its original position, as marked.
Disconnect from test setup.
Install voltage regulator VR101 in accordance with paragraph 5-15.
5-14. VOLTAGE REGULATOR VR101 ADJUSTMENT (3, Figure 5-9).
Voltage RANGE ADJUST rheostat VR101 R14. VR101 Ri4 is located on the etched circuit board (1, Figure 5-10)
inside voltage regulator VR1 01. It provides a means of varying the limits of the VOLTS ADJUST rheostat R1 01 on
Cabinet B door which optimally is set at midrange and VR101 R14 adjustment used for obtaining rated generator voltage.
This gives VOLTS ADJUST rheostat Ri01 a balanced external voltage adjustment range of ±500 V.
Stability Adjustment Rheostat VRl01 R11.
Start the generator set and operate at 60 Hz and no load.
Set VOLTS ADJUST rheostat RI 01 on cabinet B control panel to the midrange of its adjustment.
Adjust voltage RANGE ADJUST rheostat VR1 01 RI 4, located on the etched circuit board of the voltage
regulator VR101, to obtain a reading of 4160 V on the AC KILOVOLTS meter Mil01.
Rotate rheostat VR101 Rh1, located on the etched circuit board of the voltage regulator VR1I01 clockwise
while monitoring AC KILOVOLTS meter Ml 01.
When AC KILOVOLTS meter Ml01 indicator begins to oscillate, rotate rheostat VR1 01 R1 1 counter-
until the oscillation ceases.
Vary the position of VOLTS ADJUST rheostat R1 01 from fully clockwise to fully counter-clockwise and
monitor AC KILOVOLTS meter M101. Clockwise rotation should increase voltage and counterclockwise
rotation should decrease voltage. Variation in voltage through the full range of VOLTS ADJUST rheostat
Ri01 should be ±l0 percent of voltage obtained in step (3), above.
Operate the generator set at full load and monitor AC KILOVOLTS meter Ml 01.
Voltage readings noted in steps (3) and (7), above, during no load and full load operation respectively
should not vary by more than ±i percent.
Voltage stability is most critical at no load condition. Ensure that final adjustment satisfies this