PI Manufacturing AC generators - Manual (Page 14)

4.4.5 TRANSFORMER CONTROLLED EXCITATION
SYSTEM (Series 5)
This control system is identified with the digit 5 as the last digit
of the frame size quoted on the nameplate.
The excitation control is factory set for the specific voltage
shown on the nameplate and requires no adjustment.
4.5 GENERATOR SET TESTING
During testing it may be necessary to
remove covers to adjust controls exposing
'live' terminals or components. Only
personnel qualified to perform electrical
service should carry out testing and/or
adjustments.
4.5.1 TEST METERING/CABLING
Connect any instrument wiring and cabling required for initial
test purposes with permanent or spring-clip type connectors.
Minimum instrumentation for testing should be line - line or
line to neutral voltmeter, Hz meter, load current metering and
kW meter. If reactive load is used a power factor meter is
desirable.
Important ! When fitting power cables for load testing
purposes, ensure cable voltage rating is at
least equal to the genrator rated voltage.
The load cable termination should be placed
on top of the winding lead termination and
clamped with the nut provided.
Check that all wiring terminations for
internal or external wiring are secure, and
fit all terminal box covers and guards.
Failure to secure wiring and/or covers may
result in personal injury and/or equipment
failure.
4.6 INITIAL START-UP
During testing it may be necessary to
remove covers to adjust controls exposing
'live' terminals or components. Only
personnel qualified to perform electrical
service should carry out testing and/or
adjustments. Refit all access covers after
adjustments are completed.
On completion of generating set assembly and before starting
the generating set ensure that all engine manufacturer's
prerunning procedures have been completed, and that
adjustment of the engine governor is such that the generator
will not be subjected to speeds in excess of 125% of the rated
speed.
Important ! Overspeeding of the generator during initial
setting of the speed governor can result in
damage to the generator rotating
components.
In addition remove the AVR access cover (on AVR controlled
generators) and turn VOLTS control fully anti-clockwise. Start
the generating set and run on no-load at nominal frequency.
Slowly turn VOLTS control potentiometer clockwise until rated
voltage is reached. Refer to Fig. 6a, 6b, 6c, 6d or 6e for
control potentiometer location.
Important ! Do not increase the voltage above the rated
generator voltage shown on the generator
nameplate.
The STABILITY control potentiometer will have been pre-set
and should normally not require adjustment, but should this
be required, usually identified by oscillation of the voltmeter,
refer to Fig. 6a, 6b, 6c, 6d or 6e for control potentiometer
location and proceed as follows :-
1. Run the generating set on no-load and check that speed
is correct and stable
2. Turn the STABILITY control potentiometer clockwise,
then turn slowly anti-clockwise until the generator voltage
starts to become unstable.
The correct setting is slightly clockwise from this position (i.e.
where the machine volts are stable but close to the unstable
region).
Caution !
Warning !
Warning !