TM 5-6115-434-12
the volt-amp selector switch during operation of the power unit.
(3)
Indication. Normal operating indication is 120 or 240v ac as determined by the position of the volt-amp
selector switch.
e.
Volt-Amp Selector Switch (fig. 2-19).
(1)
Description. A four position rotary switch.
(2)
Purpose. Connects the ac ammeter and ac voltmeter for selective monitoring of the line-to-line and two
line-to-neutral voltages and currents. An OFF position is also provided to disconnect the ammeter and voltmeter.
f.
Load Contactor Switch (fig. 2-19).
(1)
Description. A three position toggle switch.
(2)
Purpose. In the CLOSE position the switch actuates the 60 Hz power output contactor to close, thus
connecting the 60 Hz electrical system to the external load. In the OPEN position the switch actuates the contactor to
open and disconnect the load. In the RESET position the switch resets the protective circuits in the generator control
panel if the load contactor trip light is on.
g.
Load Contactor Trip Indicator Lamp (fig. 2-19).
(1)
Description. A. filament type press-to-test lamp with a red lens.
(2) Purpose. Illuminates to indicate that the load contactor has tripped to disconnect the load from the 60 Hz
electrical system.
2-11. .400 Hz Electrical System Controls and Instruments (fig. 2-20)
a.
General. The 400 Hz electrical system controls and instruments are located on the instrument panel (fig. 2-20).
The description, purpose, and function of the 400 Hz electrical system controls and instruments for the power unit 400 Hz
electrical system are described as follows.
b.
Frequency Meter (fig. 2-20).
(1)
Description. Dial pointer gage, calibrated to indicate 388 to 412 hertz per second in 1/2 hertz per second
increments. The dial scale has a red index mark at 400 hertz per second.
(2)
Purpose. To indicate the output frequency of the 400 Hz electrical system.
(3)
Indication. Normal indication is 400 hertz per second.
c.
AC Ammeter (fig. 2-20).
(1)
Description. Dial pointer gage, calibrated to indicate percent of rated amperes. The dial is calibrated from
0 to 125 percent in 5 percent increments. The dial is colored red from 100 to 125 percent.
(2)
Purpose. To indicate the line-to-neutral current as selected through the volt-amp selector switch during
operation of the power unit.
(3)
Indication. Normal operating range is 0 to 100 percent. Ammeter readings over 100 percent indicate an
overload condition.
d.
AC Voltmeter (fig. 2-20).
(1)
Description. Dial pointer gage, calibrated to indicate 0 to 150v ac in 5 volt increments. The dial scale has
a red index mark at the 120 volt point.
(2)
Purpose. Indicates line-to-neutral voltages, as selected through the volt-amp selector switch during
operation of the power unit.
(3)
Indication. Normal operating indication is 120v ac, as determined by the position of the volt-amp selector
switch.
e.
Volt-Amp Selector Switch (fig. 2-20).
(1)
Description. A four position rotary switch.
(2)
Purpose. Connects the ac ammeter and ac voltmeter for selective monitoring of the line-to-neutral
voltages and currents. An OFF position is also provided to disconnect the ammeter and voltmeter.
f.
Output Contactor Switch (fig. 2-20).
(1)
Description. A three position toggle switch.
(2)
Purpose. In the momentary RESET position the switch actuates the 400 Hz output contactor to reset and
close the output contacts connecting the 400 Hz electrical system to the external load. When released, the switch
returns to the CLOSE position. In the OPEN position the switch actuates the contactor to open the output contacts and
disconnect the external load. The RESET function of the switch is bypassed when the emergency switch is ON.
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