MQ Power DCA300SSJU4F3 Operation Manual page 17

OPEN DELTA EXCITATION SYSTEM
Each generator is equipped with the state of the art "Open-
Delta" excitation system. The open delta system consist
of an electrically independent winding wound among
stationary windings of the AC output section.
There are four connections of the open delta A, B, C and
D. During steady state loads, the power from the voltage
regulator is supplied from the parallel connections of A to
B, A to D, and C to D. These three phases of the voltage
input to the voltage regulator are then rectified and are the
excitation current for the exciter section.
When a heavy load, such as a motor starting or a short
circuit occurs, the automatic voltage regulator (AVR)
switches the configuration of the open delta to the series
connection of B to C. This has the effect of adding the
voltages of each phase to provide higher excitation to the
exciter section and thus better voltage response during the
application of heavy loads.
The connections of the AVR to the AC output windings are
for sensing only. No power is required from these windings.
The open-delta design provides virtually unlimited excitation
current, offering maximum motor starting capabilities. The
excitation does not have a "fixed ceiling" and responds
according the demands of the required load.
DCA300SSJU4F2/F3 60 HZ GENERATOR• OPERATION MANUAL — REV. #2 (04/18/22) — PAGE 17
GENERAL INFORMATION
ENGINE
This generator is powered by a 6 cylinder, 4-cycle water
cooled, direct injection, turbocharged, air cooled EGR John
Deere 6090HFG06 diesel engine. This engine is designed
to meet every performance requirement for the generator.
Reference Table 2 for engine specifications.
In keeping with MQ Power's policy of constantly improving
its products, the specifications quoted herein are subject
to change without prior notice.
ELECTRIC GOVERNOR SYSTEM
The electric governor system controls the RPMs of the engine.
When the engine demand increases or decreases, the
governor system regulates the frequency variation to ±.25%.
EXTENSION CABLES
When electric power is to be provided to various tools or
loads at some distance from the generator, extension cords
are normally used. Cables should be sized to allow for
distance in length and amperage so that the voltage drop
between the generator and point of use (load) is held to
a minimum. Use the cable selection chart (Table 8) as a
guide for selecting proper extension cable size.