Wacker Neuson GP 3800A, Repair Manual

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Troubleshooting GP Repair
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6.17 Checking AVR’s Sensing Wires
See Graphic: wc_gr003128
There are two sensing wires feeding the Automatic Voltage Regulator
(AVR), one attached to each of the main windings. If the sensing wires
are shorted or broken, the AVR will not perform correctly. To check the
continuity of the sensing wires, carry out the following procedures:
6.17.1 Stop the engine.
6.17.2 Remove the two screws which secure the end cover to the generator
and remove the end cover.
6.17.3 Disconnect the yellow-, red-, black-, and green-marked wires from the
generator terminal strip
(h)
.
6.17.4 The first sensing wire, represented by the brown wire on the electrical
schematic, is internal to the stator. The AVR connects to this wire at
the connection point at the upper portion of the stator. Access the wire
by disconnecting the plug
(a)
. To check the wire, with one lead of your
multimeter probe the connection point
(b)
where the brown wire from
the AVR plug would connect. With the other lead, probe main winding
2 at the terminal strip
(c)
where the red-marked wire usually connects.
There should be continuity.
•
If the first sensing wire does not have continuity, replace the sta-
tor.
• If the first sensing wire has continuity, continue.
6.17.5 The second sensing wire is really a circuit. It is represented by the blue
wire and then the brown wire on the electrical schematic. This sensing
circuit runs back through the Voltage Selector Switch (VSS) where the
wiring splits with one wire running to main winding 1, another to main
winding 2. The circuit is accessed by disconnecting the plug
(d)
from
the connection point at the lower end of the stator. To check the circuit,
first check the main-winding-2 side. To do so, place the VSS in the
120V position. With one lead of your multimeter, probe the blue wire
(e)
of the plug. With the other lead, probe the generator terminal strip
(f)
where the red-marked wire is usually connected. There should be
continuity.
Next, check the main-winding-1 side. To do so, place the VSS in the
120V/240V position. With one lead of your multimeter, probe the blue
wire
(e)
of the plug. With the other lead, probe the generator terminal
strip
(g)
where the black-marked wire is usually connected. There
should be continuity.
•
If the second sensing wire (circuit) has continuity in both posi-
tions, the sensing wires feeding the AVR are OK.