Winco MD25K/C - Manual (Page 8)

Page 6 41821 60706-120
normally. If frequency 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.
D. 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 regula-
tor controls the DC exciter field voltage on brushless
generators 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 Generator set
and tested at the factory prior to shipment. No addi-
tional 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 regula-
tor senses overexcitation and automatically removes the
field current after a time delay. This time delay is
inversely proportional to the magnitude of the detected
overvoltage condition. At approximately 140 VDC, the
field voltage is removed instantaneously.
Upon detection of overexcitation 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 (mini-
mum). TO ACCOMPLISH THIS ON A MOBILE DIE-
SEL GENERATOR SET THE FIELD CIRCUIT
BREAKER MUST BE TURNED OFF FOR TEN SEC-
ONDS.
For additional information on the Basler Voltage regula-
tor model APR125-5X see Basler Electric publication
number: 9 1688 00 992.
OPERATING THE UNIT
A. SELECTING THE CORRECT
VOLTAGE
A variety of voltages are available from the three posi-
tion 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
position, all of the receptacles on the front panel are
powered.
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