Guardian Technologies 4270 manual Test 16 Check Battery Charge Rectifier, Short to Ground

Section 7

DIAGNOSTIC TESTS

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 veri- fy the functioning of the Amp Meter. If DC Amp Meter is good and no current is measured, 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 66, Wire 15 and Wire 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 0.47 to 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

15

77

Figure 7-9. – Battery Charge Rectifier

RESULTS:

1.If any of the previous steps has failed, replace the Battery Charge Rectifier.

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 66, Wire 77 and Wire 55. The Battery Charge Resistor is used as a current limiting resistor.

PROCEDURE:

1.Disconnect the Stator Leads (Wire 66 and Wire 77) from the Battery Charge Rectifier. (Be sure to disconnect Stator Lead Wire 66 “Black” from Wire 66 “Blue” connector for this test). Disconnect the Stator Lead Wire 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 66. Connect the other test lead to Stator Lead Wire 55. Normal Battery Charge Winding resistance should be measured.

3.Connect one test lead to Stator Lead Wire 77. Connect the other test lead to Stator Lead Wire 55. Normal Battery Charge Winding resistance should be measured.

4.Connect one test lead to Stator Lead Wire 55. Connect the other test lead to Stator Leads Wire 11 & 33 at the back of CB1. “Infinity” should be measured.

5.Connect one test lead to Stator Lead Wire 55. Disconnect Stator Lead Wire 2 from the DPE circuit breaker (CB2) and connect the other test lead to Wire 2. “Infinity” should be mea- sured.

6Connect one test lead to Stator Lead Wire 55. Connect the other test lead to frame ground. “Infinity” should be measured.

7.Connect one test lead to the Battery Charge Resistor terminal that Wire 55 was removed from. Connect the other test lead to frame ground. One (1) ohm should be measured. If 1 ohm was not measured, remove Wire 0 from the Battery Charge Resistor. Connect one test lead to Wire 0 and the other test lead to frame ground. “Continuity” should be measured. Repair or replace Wire 0 if defective and retest the Battery Charge Resistor.

BATTERY CHARGE WINDING RESISTANCE *

QP75D (Model 4270)

ACROSS WIRES:	OHMS
55 & 66	0.7Ω
55 & 77	0.5Ω

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