Equipment For Troubleshooting; Safety; Parts Replacement; Test Values - Hobart 140GT17P Operation And Maintenance Manual With Illustrated Parts List

OM-2029

3. Equipment for Troubleshooting

A good quality multi-scale voltohmmeter is the only instrument required for trouble shooting. 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 388318-2, is available, tests may be made
more quickly and accurately, however, the test receptacle connector (31, Fig. 1) may be used by inserting the
test points of a voltohmmeter into proper terminals of the connector. Refer to Fig. 8.

4. Safety

WARNING: EXERCISE EXTREME CARE TO AVOID CONTACT WITH HIGH
VOLTAGE LEADS AND COMPONENTS WHICH COULD CAUSE SERIOUS
SHOCK AND INJURY IF TOUCHED WHEN TROUBLE SHOOTING OR OPER-
ATING THE EQUIPMENT.

5. Parts Replacement

To lessen end item "down" time and to get a faulty machine back "on-theline" as quickly as possible, the
"black-box" concept of parts replacement is reflected in the trouble shooting chart. For example, if a com-
ponent 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 to stock.
Assemblies which lend themselves to this concept are:
Generator control tray
Over-undervoltage module
Protective relay tray
Over-underfrequency module
Voltage regulator
Overload module
Protective monitor module
Electric governor control "box"
Governor actuator
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 throughout the trouble shooting chart, where applicable, additional infor-
mation and values are given here.
Generator output at maximum
voltage regulator rheostat setting 134 V or higher
7Generator output at minimum
voltage regulator rheostat setting 108 V or lower
Overload relay trips at any value above 112 KVA in 5 minutes.
Overvoltage 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 380 Hz, resets at 385 Hz.
Overload relay trips at 125% rated load in 5 minutes.
See 2-3, Fig. 8 for typical test values at test receptacle and test box.
3-1
Page 2
September 30/89 Revised