POWER DRIVE SYSTEMS
DUNLITE UVR100 AUTOMATIC VOLTAGE REGULATOR
4
CONTROLS (cont' d)
3. SCOOP
(cont'd)
SCOOP Adjustment
As previously stated, the point at which this function operates is pre-set at the factory so as to limit. to a
safe maximum value, the voltage applied to the exciter field. This voltage varies according to the particular
size and type of alternator and should not normally require adjustment. If, however, under operational
conditions it is found that the SCOOP function is frequently re-~- ting in loss of alternator output, without
any apparent cause,,,-it may be necessary to adjust the voltage at which SCOOP operates. In such cases,
it will be necessary to contact the factory to determine the normal cut-out voltage and then carry out the
tests detailed below.
(Note: To avoid any delay in obtaining this information, please specify both the type and serial numbers of
the generating set when making enquiry.)
1. Connect a high impedance 0-50 volts DC voltmeter across the field supply terminals
positive and negative.
2. Run the generating set and apply the full rated load and note the voltage being
applied to the exciter field.
3. On engines incorporating a hand throttle, adjust the speed of the prime mover until
the field voltage equals the SCOOP cut-out voltage recommended by the factory.
4. Adjust the SCOOP control until the red SCOOP indicator LED starts to illuminate.
5. Return the hand throttle setting to normal after the final adjustment has been made.
On engines which do not incorporate a hand throttle, the load should be increased
to achieve the field volts as specified by the factory.
DO NOT run the set on overload for extended periods when carrying out these tests, or the alternator may
sustain permanent damage, and UNDER NO CIRCUMSTANCES ALLOW THE SET TO RUN WITH THE
FIELD VOLTS IN EXCESS OF THE MAXIMUM VALUE SPECIFIED BY THE FACTORY.
It is possible to adjust the SCOOP to operate at a lower voltage, thereby reducing the tolerable degree of
overload; however, when doing so account must be taken of the increase in field volts required to cover
low power factor loads and high ambient temperatures.
The SCOOP indicator will illuminate as soon as an overload or low speed condition arises and will remain
illuminated after the SCOOP has de-energised the alternator.
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