Section 4 • Troubleshooting
September 2008
4 - 8
T70, T90 & T120 Super Quiet Generator
Part No. 134277
Procedure for changing the
voltage potentiometer
THIS EQUIPMENT USES HIGH VOLTAGE
CIRCUITS CAPABLE OF CAUSING SERIOUS
INJURY OR DEATH! EXCERCISE EXTREME
CAUTION AROUND ANY ELECTRICAL
COMPONENT WHEN OPERATING THIS UNIT.
INSTALLATION AND ANY WORK PERFORMED
ON THIS UNIT SHOULD BE DONE ONLY BY A
QUALIFIED ELECTRICIAN.
•
Make sure generator is turned off and e-stop is
engaged before opening control panel.
•
Locate the two wires going to the back of the
potentiometer. Both wires will be white with a
red stripe.
•
Disconnect both wires.
•
Once the wires are loose, go to the front of the
control panel and loosen the lock nut holding
the potentiometer.
•
Put the new potentiometer in its place and
retighten lock nut.
•
Reattach the disconnected wires that were
disconnected in step 3.
•
After completing the installation of the new
potentiometer go back and check all
connections to make sure everything is tight
and that no connections are loose, this includes
all other wiring on the back of the control panel
and on the inside of the control box.
•
You should now be able to restart the generator
and check for proper operation.
If any further adjustment is needed to the voltage
of the generator please call
TEREX
at 1-800-433-
3026 for assistance.
•
After performing the initial checks above,
remove the field wires from the voltage
regulator (F1 or X is positive and F2 or XX is
negative). Connect the b to the F1 or X
wire and battery - to the F2 or XX wire. Start the
engine and check for the rated voltage.
Hooking this up incorrectly will reverse
polarity and could damage the voltage
regulator and /or generator end.
This check
should correct any voltage problems. If your
voltage does not come up to the rated voltage,
this indicates an internal problem with the
generator end. The output should be close to
proper voltage. Also, if the unit comes up to
voltage, check for even reading across the lines
if they are not this would mean you probably
have a problem with the wiring of the switch or
generator. If the generator voltage reads
correctly you know there is not a problem with
the generator end. Your problem is more than
likely with the voltage regulator. In this case,
you should contact the
TEREX
service
department.
•
If the voltage is uneven between the legs when
you apply 24 volts to the field wires you need to
recheck your wiring connections.
(If you can
not find the problem hard wire the
generator!)
After you have the field wire
connected start the unit again and check your
output voltage. It may still be necessary to flash
the fields to restore residual voltage. This needs
to be done with the unit off and the field wires
removed.
(Do not flash the regulator, flash
the field wires)
•
As with any electrical device use extreme
caution when working around a running
generator it could cost you your life. Observe
proper polarity when working with the regulator
so you don’t break something that is not broken
to begin with, and if you are ever in doubt, ask.
INSTALLATION AND ANY WORK PERFORMED
ON THIS UNIT SHOULD BE DONE ONLY BY A
QUALIFIED ELECTRICIAN.
Procedure for testing
generator with no output
(cont.)
TROUBLESHOOTING
