Bryant ASPAS1BBA007, Руководство по диагностике и ремонту

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Page 41
SECTION 2.4
DIAGNOSTIC TESTS
AC GENERATORS
RESULTS:
1. If the resistance reading is correct, check your VOM
meters fuse and repeat Test 4.
2. If INFINITY is measured on your VOM meter, go to
Test 9.
TEST 9 - CHECK BRUSHES
AND SLIP RINGS
DISCUSSION:
The function of the brushes and slip rings is to
provide for passage of excitation current from
stationary components to the rotating rotor. Brushes
are made of a special long lasting material and
seldom wear out or fail. However, slip rings can
develop a tarnish or film that can inhibit or offer a
resistance to the flow of electricity. Such a non-
conducting film usually develops during non-operating
periods. Broken or disconnected wiring can also
cause loss of excitation current to the rotor.
Figure 7. Checking Brushes and Slip Rings
PROCEDURE:
1. Disconnect connector C2 (deutsch connector closest to
the back panel). Refer to Figure 5 and Figure 6 in
Section 2.4.
2. Set a VOM to measure resistance.
3. Connect one meter test lead to Pin 9 (Wire 0) of the C2
connector (female side). Connect the other meter test
lead to Pin 10 (Wire 4) of the C2 connector (female
side). Rotor resistance should be measured see
specifications on inside front cover. If rotor resistance is
not measured proceed to step 4. If rotor resistance is
measured proceed to step 12.
4. See figure 7. Carefully inspect brush wires; make sure
they are properly and securely connected.
5. Wire 0 from the negative (-) brush terminal connects to
Pin 9 of the C2 connector. Test this wire for an open
condition. Remove wire 0 from the brush assembly.
Connect one meter test lead to wire 0. Connect the
other test lead to Pin 9 (wire 0) of the C2 connector (
female side). CONTINUITY should be measured. If
INFINITY is measured repair or replace wire 0 between
the brush assembly and the C2 connector.
6. Wire 4 from the positive (+) brush terminal connects to
Pin 10 of the C2 connector.Test this wire for an open
condition. Remove wire 4 from the brush assembly.
Connect one meter test lead to Wire 4. Connect the
other meter test lead to Pin 10 (wire 0) of the C2
connector (female side). CONTINUITY should be
measured. If INFINITY is measured repair or replace
wire 4 between the brush assembly and the C2
connector.
7. Connect one meter test lead to wire 4 Connect the other
meter test lead to frame ground. INFINITY should be
measured. If CONTINUITY is measured a short to
ground exists on wire 4 repair or replace wire 4 between
the brush assembly and the C2 connector.
8. If continuity was measured in steps 5 and 6 proceed to
step 9.
9. Disconnect wires 0 and 4 from the brush assembly.
Remove the brush assembly from the bearing carrier.
Inspect the brushes for excessive wear,damage.
10.Inspect the rotor slip rings. If they appear dull or
tarnished, they may be polished with a fine sandpaper.
DO NOT USE METALLIC GRIT TO POLISH SLIP
RINGS.
11.If brush assembly and slip rings look good proceed to
Test 10 ( Test Rotor assembly)
12.Wire 0 connects from the C2 connector to the control
panel ground lug. Connect one meter test lead to Pin 9
(Wire 0) of the C2 connector (male side). Connect the
other meter test lead to the ground terminal in the
control panel. CONTINUITY should be measured. If
INFINITY is measured repair or replace wire 0 between
the C2 connector and the ground terminal.
13.Remove wire 4 from the voltage regulator.
14.Connect one meter test lead to Pin 10 (wire 4) of the C2
connector (male side). Connect the other meter test
lead to Wire 4 removed from the Voltage regulator.
CONTINUITY should be measured. If INFINITY is
measured repair or replace wire 4 between the C2
connector and the voltage regulator.
PART 2