Multiquip DCA70SSJU3 - Manual (Page 18)

PAGE 18 — DCA-70SSJU3 (60 HZ) — OPERATION AND PARTS MANUAL — REV. #0 (05/10/06)
DCA-70SSJU3 (60 Hz) — GENERAL INFORMATION
DCA-70SSJU3 Whisperwatt™ Generator Familiarization
The MQ Power Model DCA-70SSJU3 is a 56 kW, 60 Hz
generator
(Figure 5) 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
■ ■ ■ ■ ■ Oil Pressure Gauge
■ ■ ■ ■ ■ Charging Ammeter Gauge
■ ■ ■ ■ ■ Fuel Level Gauge
■ ■ ■ ■ ■ Pre-heat Lamp
■ ■ ■ ■ ■ Panel Light/Panel Light Switch
■ ■ ■ ■ ■ ECU Controller
Generator Control Panel
The “Generator Control Panel” is provided with the following:
■ ■ ■ ■ ■ Frequency Meter (Hz)
■ ■ ■ ■ ■ AC Ammeter (Amps)
■ ■ ■ ■ ■ AC Voltmeter (Volts)
■ ■ ■ ■ ■ Ammeter Change-Over Switch
■ ■ ■ ■ ■ Voltmeter Change-Over Switch
■ ■ ■ ■ ■ Voltage Regulator
■ ■ ■ ■ ■ 3-Pole, 175 amp Main Circuit Breaker
■ ■ ■ ■ ■ “Control Box” (located behind the Gen. Control Panel)
■ ■ ■ ■ ■ Automatic Voltage Regulator
■ ■ ■ ■ ■ Current Transformer
■ ■ ■ ■ ■ Over-Current Relay
■ ■ ■ ■ ■ Voltage Rectifier
■ ■ ■ ■ ■ Starter Relay
■ ■ ■ ■ ■ Voltage Selector Switch
Output Terminal Panel
The “Output Terminal Panel” is provided with the following:
■ ■ ■ ■ ■ Three 120/240V output receptacles (CS-6369), 50A
■ ■ ■ ■ ■ Three auxiliary circuit breakers, 50A
■ ■ ■ ■ ■ Two 120V output receptacles (GFCI), 20A
■ ■ ■ ■ ■ Two GFCI circuit breakers, 20A
■ ■ ■ ■ ■ Five output terminal lugs (3Ø power)
■ ■ ■ ■ ■ Battery Charger (Optional)
■ ■ ■ ■ ■ Water Heater (Optional)
Open Delta Excitation System
The DCA-70SSJU3 (60 Hz)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.