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DCA-45USI FAMILIARIZATION
Generator
The MQ Power Model DCA-45USI (Figure 4) is a 36 kW
generator that is designed as a high quality portable (requires
a trailer for transport) power source for telecom sites, lighting
facilities, power tools, submersible pumps and other
industrial and construction machinery.
Engine Operating Panel
The "Engine Operating Panel" is provided with the following:
Tachometer
Water Temperature Gauge/ Alarm Lamp
Oil Pressure Gauge/ Alarm Lamp
Charging Ammeter Gauge
Pre-Heat Lamp
Panel Light
Panel Light Switch
Ignition/Preheat Switch
Fuel Gauge
Fuel Filter Water Level Alarm Lamp
Generator Control Panel
The "Generator Control Panel" is provided with the following:
Output Voltage Adjustment Knob
Frequency Meter (Hz)
AC Ammeter (Amps)
AC Voltmeter (Volts)
Ammeter Change-Over Switch
Voltmeter Change-Over Switch
Voltage Regulator
3-Pole, 110 amp Main Circuit Breaker
Output Terminal Panel
The "Output Terminal Panel" is provided with the following:
Three 120/240V output receptacles (CS-6369), 50 amps
Three auxilliary circuit breakers, @50 amps
Two 125 VAC output receptacles, (GFCI), 20 amps
Two GFCI circuit breakers @ 20amps
Five output terminal lugs (3Ø power)
Control Box
The "Control Box" is provided with the following:
Automatic Voltage Regulator
Current Transformer
Emergency Relay
Over-Current Relay
PAGE 20 — DCA-45USI — OPERATION AND PARTS MANUAL (STD) — REV. #2 (04/22/05)
DCA-45USI — GENERAL INFORMATION
Open Delta Excitation System
The DCA-45USI 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.
Engine
The DCA-45USI is powered by a 4 cycle, water cooled, turbocharged
Isuzu BB-4JG1T diesel engine. This engine is designed to meet
every performance requirement for the generator. Reference Table 1
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.
The basic controls and indicators for the DCA-45USI generator are
addressed on the following pages.
Mechanical Governor System
The mechanical governor system control the RPM of the engine.
When the engine demands increase or decrease, the mechanical
governor system regulates the frequency variation to within ±.5%.
The electronic governor option decreases the frequency variation
to within ±0.25%.
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 5 ) as a guide for selecting proper extension cable size.
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