Check Battery Charge Output; Check Battery Charge Rectifier; Battery Charge Resistor - Guardian 4700 Repair Manual

TEST 15 - CHECK BATTERY CHARGE
OUTPUT
DISCUSSION:
The Battery Charge system consists of a center tap
Battery Charge Winding, a Battery Charge Rectifier,
and a Battery Charge Resistor. During normal opera-
tion the battery charge output will vary between 1 to 2
amps, depending on the load applied to the genera-
tor.Battery Charge Winding Stator Lead Wire No. 66
is tapped at the Battery Charge Rectifier and connect-
ed to the Engine Control Circuit Board at Pin location
J1-10, and is used as a signal for Starter lockout.
PROCEDURE:
1. Disconnect Wire No. 15 from the Battery Charge Rectifier (cen-
ter terminal). Wire No. 15 is the fused battery supply.
2. Set your VOM to measure DC Amps. Connect the positive (+)
test lead to the center terminal of the Battery Charge Rectifier.
Connect the negative (-) test lead to Wire No. 15 previously
disconnected.
3. Start the generator. The amp reading on the VOM should be
approximately 0.8 Amps. Apply full load to the generator. The
amp reading should increase to approximately 2 Amps.
RESULTS:
1. If amperage was measured between 0.8 to 2 Amps in Step 2
and Step 3, the charging system is working.
2. If no amperage was measured, check the VOM fuses and verify
the functioning of the Amp Meter. Verify that the generator fuse
F1 is not blown. If the fuse is bad, replace the fuse and retest.If
meter and fuse are both good, go to Test 16.
TEST 16 - CHECK BATTERY CHARGE
RECTIFIER
DISCUSSION:
The Battery Charge Rectifier (BCR) is a full wave rectifier.
PROCEDURE:
1. Disconnect Wire No. 66, Wire No. 15 and Wire No. 77 from the
Battery Charge Rectifier.
2. Set the VOM to the Diode Test range. Connect the negative (-)
test lead to the center terminal of the BCR. Connect the posi-
tive (+) test lead to an outer terminal. The meter should mea-
sure approximately 0.5 volts. Now connect the positive test
lead to the other outer terminal. Again, the meter should mea-
sure approximately 0.5 volts.
3. Connect the positive (+) test lead to the center terminal of the BCR.
Connect the negative (-) test lead to to an outer terminal. The
meter should measure "Infinity." Connect the negative test lead to
the other outer terminal. Infinity should once again be measured.
Short to Ground:
4. Set the VOM to measure resistance. Connect the positive (+)
test lead to the case housing of the BCR. Connect the negative
(-) test lead to an outer terminal. "Infinity" should be measured.
Now connect the negative test lead to the BCR center terminal.
Infinity should be measured. Next, connect the negative test
lead to the remaining outer BCR terminal. Once again "Infinity"
should be measured.
66
Figure 7-10. – Battery Charge Rectifier
RESULTS:
1. If any of the previous steps has failed, replace the Battery
Charge Rectifier.
2. If the BCR tests good, go to Test 17.
TEST 17 - CHECK BATTERY CHARGE
WINDINGS / BATTERY CHARGE RESISTOR
DISCUSSION:
The Battery Charge Winding (BCW) produces AC
voltage that is delivered to the Battery Charge
Rectifier. The Battery Charge Winding is a center
tapped winding consisting of the following Stator
Leads: Wire No. 66, Wire No. 77 and Wire No. 55.
The Battery Charge Resistor is used as a currant lim-
iting resistor.
PROCEDURE:
1. Disconnect the Stator Leads (Wire No. 66 and Wire No.
77) from the Battery Charge Rectifier. (Be sure to
disconnect Stator Lead Wire No. 66 "Black" from
Wire No. 66 "Blue" connector for this test). Disconnect
the Stator Lead Wire No. 55 from the Battery Charge Resistor.
2. Set the VOM to measure resistance at the "R x 1" scale.
Connect one test lead to Stator Lead Wire No. 66. Connect the
Section 7
DIAGNOSTIC TESTS
15
77
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