Should the green light come on, then "A" lead is not
substantial changes in meter readings and the pointer
grounded. Disregard the red light as it has no bearing
will fall outside of the cross hatched area.
on this test.
4-8. FIELD CHECKING THE UNIVERSAL ATTITUDE
4-9.
FIELD CHECKING THE ELECTRIC GYRO
GYRO INDICATOR TYPE 1-1.
INDICATORS TYPE C-1, J-3,A-1, E-1,J-7, J-8, and C-
a. POWER CHECK. The following procedure
5.
shall be followed in checking the power supplied to the
instrument under test:
a. POWER CHECK. The following procedure
shall be followed in checking the power supplied to the
(1) LEAD CONNECTIONS.
instrument under test.
(a) Connect lead 47B7489, which is the
(1) LEAD CONNECTIONS,
power lead, to the 4-pin receptacle of the tester. The
receptacle end of this lead shall be connected to the 4-
(a) Connect lead 47B7489, which is the
pin plug of lead 47B7494.
power lead, to the 4-pin receptacle of the tester. The
receptacle end of this lead shall be connected to the 4-
(b) Disconnect the 5-pin plug from the
pin plug of lead 47B7495.
back of the indicator and connect to the receptacle of
lead 47B7494. Connect the 5-pin plug of this lead to the
(b) Disconnect the 3-pin plug from the
back of the indicator.
back of the indicator and connect to the receptacle of
lead 47B7495. Connect the 3-pin plug of this lead to the
(2) TEST PROCEDURE.
back of the indicator.
(a) Turn switch no. 1 of the tester to
(2) TEST PROCEDURE. Turn switch no. 1
"POWER CHECK" position; switch no. 5 to the "28 v D-
of the tester to "POWER CHECK" position; switch no. 5
C" position, and turn on the ship's power. After the rotor
to "AB" position, and turn on the ship's power. After the
of the indicator has come up to speed; a reading of the
rotor of the indicator has come up to speed, a reading of
voltmeter shall be taken. It shall be 28 volts plus or
the voltmeter shall be taken. It shall be 115 volts plus or
minus 2.
minus 5. Switch no. 5 shall be rotated to the other two
phases of the 115 volt, 400 cycle current, BC and AC
(b) Switch no. 5 shall be rotated to the
respectively, and a reading of the voltmeter taken at
three phases of the 115 volt, 400 cycle current, AB, BC
each point. The reading shall be 115 volts plus or minus
and AC, respectively, and a reading of the voltmeter
5. The frequency of the 115 volt current shall be 400
taken at each point. During this test, the pointer of the
cycles plus or minus 16 cycles as indicated by the
voltmeter in the tester shall fall at 115 v plus or minus 5.
frequency meter of the tester. The phase rotation shall
The frequency of the 115 volt current shall be 400
be ABC as indicated by the green panel light. If the red
cycles plus or minus 16 cycles as indicated by the
light comes on, the phase rotation is wrong. Also in
frequency meter of the tester. The phase rotation shall
conjunction with phase rotation, the "A" leg of the three
be ABC as indicated by the green panel light. If the red
phase current should always be grounded, should the
light comes on, the phase rotation is wrong. Also in
system have a ground. To check this turn switch no. 1
conjunction with phase rotation, the "A" leg of the 3 -
to "GROUND CHECK" position, connect test lead no.
phase current should always be grounded on a J-1
50A7513 to the ground test jack and connect the other
installation. To check this, turn switch no. 1 to
end of this lead to the aircraft structure. The green light
"GROUND CHECK" position, connect test lead no.
shall not light. Should the green light come on, then "A"
50A7513 to the ground test jack and connect the other
leg is not grounded. Disregard the red light as it has no
end of this lead to the aircraft structure. The green light
bearing on this test.
shall not light.
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