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PAGE 20 — DCA-25SSAI — PARTS AND OPERATION MANUAL—FINAL COPY (06/30/01)
DCA-25SSAI — GENERAL INFORMATION
DCA-25SSAI FAMILIARIZATION
Generator
The MQ Power Model DCA-25SSAI is a 20 kW
genergener
genergener
gener
atorator
atorator
ator
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:
z
Tachometer
z
Water Temperature Gauge
z
Oil Pressure Gauge
z
Charging Ammeter Gauge
z
Fuel level gauge
z
Engine Throttle Lever
z
Pre-Heat Light
z
Alarm Lights
z
Panel Light
z
Panel Light Switch
z
Starter Switch
Generator Control Panel
The “Generator Control Panel” is provided with the following:
z
Output Voltage Adjustment Knob
z
Frequency Meter (Hz)
z
AC Ammeter (Amps)
z
AC Voltmeter (Volts)
z
Ammeter Change-Over Switch
z
Voltmeter Change-Over Switch
Output Terminal Panel
The “Output Terminal Panel” is provided with the following:
z
Three 120/240V output receptacles, 50 amp
z
Two 120V input receptacles, 20 amp
z
3 Load Circuit Breakers 240V @50 amps
z
2 Load GFCI Circuit Breakers 120V@ 20amps
Control Box
The “Control Box” is provided with the following:
z
Main Circuit Breaker 60 amps
z
Over-Current Relay
Engine
The DCA-25SSAI is powered by a 4 cycle, water cooled,
turbocharged Isuzu QD60(C640)
diesel diesel
diesel diesel
diesel
engine. This engine
is designed to meet every performance requirement for the
generator. Reference Table 5, page 19 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-25SSAI
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 ±1.5%. The electronic governor option in-
creases frequency variation to ±.25%.
Open Delta Excitation System
The DCA-25SSAI generator is equipped with the state of
the art "
Open-DeltaOpen-Delta
Open-DeltaOpen-Delta
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 leads: A, B, C and D. During light loads, the
power to the
AA
AA
A
utomatic utomatic
utomatic utomatic
utomatic
VV
VV
V
oltage Regulator oltage Regulator
oltage Regulator oltage Regulator
oltage Regulator
(AVR) is supplied
from the leads parallel connections of B&C. When loads
increase, the AVR switches and accepts power from leads
A&D. The output of leads A&D increase proportionally with
load. This of adding the voltages to each phase provides
better voltage response during 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 ceilingfixed ceiling
fixed ceilingfixed ceiling
fixed ceiling
" and responds
according the demands of the required load.