Electrical Maintenance
45
14. Stop the unit.
15. Use the readings obtained previously to
determine the problem by referring to the
Diagnosis Chart below.
NOTE: This assumes that the alternator did
not charge properly prior to the full field test.
Field Current Test
This test checks the field windings, brushes, and
slip rings Perform this test with the Zone 1 On/Off
switch in the Off position.
1. Attach a clamp-on ammeter to the 2A wire
near the B+ terminal on the alternator.
2. Connect a jumper wire between the F2
terminal on the alternator and a chassis
ground, and note the ammeter reading.
3. The ammeter reading indicates field current.
The following chart shows the field current for
a 120 amp alternator with 12 volts applied to
the field:
a. No field current or a low field current
indicates an open circuit or excessive
resistance in the field circuit. Replace the
voltage regulator and brush assembly,
inspect the slip rings and repeat the test. If
the brushes are not the problem, replace
the rotor or the alternator.
b. High field current indicates a short in the
field circuit. Repair or replace the
alternator.
Alternator Rating
Field Current
@ 12 Volts
120 Amp
2.0 to 5.0 Amps
Diagnosis Chart
Amperage in 2A
Voltage at B+
Problem/Solution
At or above rated output
At or above battery voltage and
increasing
Voltage regulator defective / Replace
voltage regulator and brush assembly
Approximately 60 percent
of rated output
Approximately equal to battery voltage
and does not change, or rises slightly
Receiver diode defective / Repair or replace
alternator
Low or no output
Less than or equal to battery voltage
and decreasing
Stator windings, field windings, brush or
diode defective / Perform Field Current Test
to check brushes and field coil, or replace
alternator
Содержание Spectrum DE 30-2
Страница 4: ...4...
Страница 12: ...Safety Precautions 12...
Страница 16: ...Specifications 16...
Страница 31: ...Unit Description 31 1 Access Panels 2 Defrost Dampers Figure 12 Back View of Unit 1 2 AGA215...
Страница 42: ...Operating Instructions 42...
Страница 48: ...Electrical Maintenance 48...
Страница 106: ...Structural Maintenance 106...
Страница 110: ...Mechanical Diagnosis 110...
Страница 114: ...Remote Evaporator Specifications 114...
Страница 116: ...Remote Evaporator Maintenance Inspection Schedule 116...
Страница 122: ...Remote Evaporator Electrical Maintenance 122...
Страница 126: ...Remote Evaporator Refrigeration Service Operations 126...
Страница 128: ...Remote Evaporator Structural Maintenance 128...
Страница 130: ...Remote Evaporator System Diagnosis 130...
Страница 134: ...Wiring and Schematic Diagrams Index 134...
Страница 135: ...135 Schematic Diagram Page 1 of 2...
Страница 136: ...136 Schematic Diagram Page 2 of 2...
Страница 137: ...137 Wiring Diagram Page 1 of 4...
Страница 138: ...138 Wiring Diagram Page 2 of 4...
Страница 139: ...139 Wiring Diagram Page 3 of 4...
Страница 140: ...140 Wiring Diagram Page 4 of 4...