Power Delivery; Discontinue Power Delivery; Stopping The Engine - Hobart 60PL20 Operation And Maintenance Manual

OM-2053
D. Power Delivery
(1) Place engine-generator control switch (15) in BUILD-UP-VOLTAGE position momentarily, then al-
low it to position itself in GEN position. The electric governor will immediately increase engine speed
to 2000 RPM and maintain it.
(2) Observe generator instruments. Frequency meter (1) should indicate exactly 400 Hz. Voltmeter
(2) should indicate 115 V AC when line switch (5) is in ANY line-to-neutral position, A-N, B-N, or C-N,
and should read 200-V AC when it is in any line-to-line position, A-B, B-C, or C-A.
(3) The final step in delivering power is closing the load contactor. When satisfactory frequency and
voltage values are indicated by the instruments, close the load contactor by momentarily placing the
load contactor control switch (17) in the top (spring loaded) , CLOSE position. The green indicating
light (19) should glow at once to indicate that the load contactor is closed and power is available at
the aircraft. As soon as the light glows, release the switch. It will automatically return to the center ON
position.
NOTE: If the indicating light (19) should "go-out" as soon as the switch is released, and no fault
lights are ON, it indicates that 28.5-V DC holding current is not being supplied from the aircraft
to the plug-interlock relay.
Correct the condition an again operate the load contactor control switch (17) as above.
(4) It is recommended that the operator check output voltage and current in each of the three phases
early in the power delivery run. Use the meter switch (4) to select the phase and line-to-line or line-to-
neutral voltage. If the load is changing, it is good operating practice to observe the instruments until
load conditions stabilize.
(5) A condition of overvoltage, undervoltage, underfrequency, overfrequency, or overload in the out-
put circuit will automatically open the load contactor and turn on the applicable indicating light to sig-
nal the operator which of the above faults caused the protective monitor system to operate. After the
fault has been corrected, press the reset switch (6) to turn off the indicating light and reset the protec-
tive relay system. Proceed with power delivery by operating the load contactor switch.
E. Discontinue Power Delivery
(1) Place the load contactor switch (17) in OFF position. Green light (19) should go OFF immediately
to indicate that the load contactor has opened and power is no longer being delivered to the aircraft.
(2) Place engine-generator control switch (15) in IDLE position.
(3) Disconnect output cable from aircraft.
WARNING: HIGH VOLTAGE - Electric shock or fire can kill! Never disconnect
the output cable while power is being delivered.
F. Stopping the Engine
(1) Allow the engine to idle a few minutes before stopping, to permit cooling.
(2) To stop the engine, move the START-RUN-STOP switch (24) to the STOP (down) position.
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December 31/91 Revised