Hobart 6824-1, Operation And Maintenance Manual, Page: 92 / 214

3. Equipment for Troubleshooting
A good quality multi-scale volt-ohmmeter is the only instrument required for troubleshooting. At least
two “jumper” leads with “alligator” clips and test prods will be required. The 12-V, engine electrical
system may be used as a 12-V DC power source.
If a test box, part number 388318A -2, is available tests may be made more quickly and accurately,
however, the test receptacle connector may be used by inserting the test points of a volt-ohmmeter into
proper terminals of the connector. Refer to Fig. 8.
4. Safety
Electric shock and moving parts can kill! Exercise extreme care to avoid contact
with high voltage parts or leads and moving parts when trouble shooting or
operating the equipment. Remove jewelry such as rings and watch.
5. Parts Replacement
To lessen end item “down” time and to get a faulty machine back “on-the-line” as quickly as possible,
the “black-box” concept of parts replacement is reflected in the troubleshooting chart. For example, if a
component in the protective relay tray is defective, the quickest way to remedy the situation is to
replace the complete tray assembly and send the old tray for repair.
Assemblies which lend themselves to this concept are:
•
Generator control tray
•
Protective relay tray
•
Voltage regulator
•
Overload module
•
Protective monitor module
•
Electric governor control “box”
•
Governor actuator
•
Over-undervoltage module
•
Over-underfrequency module
The above items are in addition to normally replaced items such as fuel pump, injectors, relays, etc.
6. Test Values
Although test values are provided, where applicable, throughout the troubleshooting chart additional
information and values are given here.
•
Generator output at maximum voltage regulator rheostat setting 134 V or higher
•
Generator output at minimum voltage regulator rheostat setting 108 V or lower
•
Overload relay trips at any value above 125% load in 5 minutes or less.
•
Overload relay trips at 130 to 134 V AC, resets at 125 V AC.
•
Undervoltage relay trips at 93 to 102 V AC, resets at 110 V AC.
•
Undervoltage time delay circuit functions in 4 to 12 seconds.
•
Overfrequency relay trips at 415 to 425 Hz, resets at 410 Hz.
•
Underfrequency relay trips at 375 to 385 Hz, resets at 385 Hz.
•
Overload relay trips at 125% rated load in 5 minutes.
WARNING
OM-499
3-1 May 31/94 Revised
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