Winco MDS50 - Manual (Page 8)

Page 6
has not returned at the end of this time period, the engine
oil pressure status is observed to determine whether the
engine is actually running or stopped. If the engine has
stopped (i.e.- air in fuel, etc., the unit is shut down with
an “overspeed” indication and alarm.
b. “Overspeed” indicator light can mean a loss of
control signal during the previous run period (i.e.- bat.
charging alternator belt broken).
TROUBLE SHOOTING HINT: This is of particular note
since the tendency is to pursue only overspeed faults.
The overspeed signal source (battery charging alternator)
is a key component in this system and must be checked
out thoroughly whenever an “OS” shutdown occurs.
Please note: The controller does not provide protection
against loss of signal during start-up. A shutdown with
alarm due to any of the above conditions will prevent any
subsequent operation of the generator set. The control
switch on the control panel must be momentarily placed
in the “off” position to reset.
E. VOLT/HERTZ VOLTAGE REGULATOR
The purpose of the voltage regulator is to maintain the
voltage output of the Generator Set within a specified
percentage of its rated output from no load to full load.
The voltage regulator controls the voltage output of the
main generator by regulating the amount of current
delivered to the exciter field.
1. Location -Access to the voltage regulator assembly
is gained by removing the control panel access door
located through the left rear housing door.
2. Description - The Basler model VR63-4C voltage
regulator is a completely encapsulated unit. The regulator
controls the DC exciter field voltage on brushless genera-
tors to regulate the output voltage. Regulation is provided
by sensing the generator output voltage, converting it to
a DC signal and comparing the signal to a reference
voltage signal. An error signal is developed and used to
control the DC field power in order to maintain a constant
generator output.
3. Operation of Voltage Regulator - The voltage
regulator has been installed in the Mobile Diesel Genera-
tor set and tested at the factory prior to shipment. No
additional set-up is required when changing from one
voltage to another. The only adjustment required is to
fine tune the exact voltage you want using the voltage
adjustment rheostat located on the front panel. The
adjustment range is 10% of the nominal voltage.
Some minor changes must be made for 50 cycle opera-
tion. Refer to 50 Hz operation later in this section for set-
up procedures.
a. During periods of operation at reduced speed
use the field circuit breaker to remove the power from the
regulator.
b. If the exciter field voltage exceeds 95 VDC, the
regulator senses over excitation and automatically
removes the field current after a time delay. This time
delay is inversely proportional to the magnitude of the
detected over voltage condition. At approximately 140
VDC, the field voltage is removed instantaneously.
Upon detection of over excitation and the resulting field
voltage shutdown, the regulator will not reset or return to
an operational condition until the generator output voltage
drops to less than 6 VAC for ten seconds (minimum). TO
ACCOMPLISH THIS ON A MOBILE DIESEL GENERA-
TOR SET THE FIELD CIRCUIT BREAKER MUST BE
TURNED OFF FOR TEN SECONDS.
OPERATING THE UNIT
A. SELECTING THE CORRECT VOLTAGE
A variety of voltages are available from the three position
selector switch. The three basic connection patterns are,
Delta (120/240), Low or Parallel WYE (120/208), and
High WYE (277/480). Single phase 120/240 is available
with the switch in the 120/240 (Delta) position.
Before connecting this unit to a distribution panel or any
other loads, be sure you have the selector switch set for
the right voltage and locked. If you have any doubts as to
the voltage in your area compare your incoming power or
load name plates to the voltage table below.
1. 120/240 Three Phase* (Delta/Series configuration) -
This configuration will produce the following line-to-line
and line-to-neutral voltage. In this selector switch posi-
tion, all of the receptacles on the front panel are pow-
ered.
L1 - L2 - L3 240 Volts three phase
L1 - L2 240 volts single phase
L2 - L3 240 volts single phase
L1 - L3 240 volts single phase
L1 - N 120 Volts
L2 - N 120 Volts
L3 - N 208 volts
*This selector position is also used for single phase 120/
240 output, using only the L1 and L2 leads. The L3 three
phase output lead is the “wild” leg in the delta configura-
tion and is used only for three phase loads.
2. 120/208 Three Phase (Low/Parallel WYE configura-
tion) This configuration will produce the following line-to-
line and line-to-neutral voltage. Use of this selector
switch position allows utilization of the 120 volt receptacle