Briggs & Stratton 030430, Service And Repair Manual

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12 BRIGGSandSTRATTON.COM
In normal generator operation, upon startup there is some
“residual” magnetism in the rotor to get the generating
process started. Residual magnetism is what is left in the
rotor after the unit has shut down. When residual magnetism
is lost, the unit will have an output voltage that will remain
at zero. This usually occurs if the unit is out of use for a long
period of time. If residual magnetism is lost, it can usually be
restored by “fl ashing the fi eld” with a simple process involv-
ing a (DC) battery.
1. Obtain a 12VDC battery and two jumper leads with
alligator clip ends.
2. Remove the four screws and remove the rear bearing
cover.
3. Locate the brush/bridge rectifier inside the rear bearing
carrier.
4. Remove wires #2 and #6 (red and blue) from the
rectifier terminals J1 and J2.
NOTICE: Isolate wires #2 and #6. Do not let the terminals
touch or contact ground.
5. Apply 12VDC across terminals J1 and J2, polarity is
not important. Connect battery negative last (Figure 6).
6. Start the engine and allow it to stabilize at running
speed.
7. After about 5 seconds, shut the engine down.
8. Disconnect the battery wires from the brushes.
(Disconnect negative (-) battery wire last).
9. Restart the unit and check once again for proper (AC)
output voltage.
• If output voltage is within specifications,
troubleshooting is complete.
• If output voltage is not within specifications, proceed to
Test 3- Isolate Control Panel.
WARNING Battery posts, terminals and other
components in this product and related accessories
contain chemicals known to the State of California to
cause cancer, birth defects, or other reproductive harm.
Wash hands after handling.
WARNING Starter and other rotating parts could
entangle hands, hair, clothing, or accessories
resulting in serious injury.
NEVER operate generator without protective housing or •
covers.
DO NOT wear loose clothing, jewelry or anything that •
could be caught in the starter or other rotating parts.
Tie up long hair and remove jewelry. •
TEST 1 - Check Voltage and Frequency Output
1. Disconnect any electrical loads.
2. Check all circuit breakers and verify they are ON.
3. Set meter to measure AC volts.
4. Connect the meter test leads into a 120 VAC generator
receptacle.
5. Connect a frequency meter into a generator receptacle.
6. Start the generator engine, let it stabilize and warm up.
7. Read the “no-load” voltage and frequency, and analyze
the results as follows:
• If zero volts or less than 1VAC is indicated proceed to
Test 2 - Flash the Field.
• If low voltage is indicated, but readings is above 1VAC
and AC frequency is normal proceed to Test 3 - Isolate
the Control Panel.
• If low voltage is indicated, but reading is above 6VAC
and AC frequency is low the engine governor may need
adjustment. Refer to the appropriate engine manual for
further governor troubleshooting.
TEST 2 - Flash the Field
WARNING Generator voltage could cause electrical
shock or burn resulting in death or serious injury.
DO NOT touch bare wires or receptacles. •
DO NOT allow unqualified persons or children to operate •
or service generator.
Figure 6