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|  4.5.3.2 Connect a jumper across mins M-N of P201 and apply 26 plus or
minus 1 volts dc across pins M-P of P201 (pin M being negative). The gyro
shall cage as specified in 3.3.1.5. The servomotor brake should be un-
locked. Check that it is by manually moving the gear meshed with the
servomotor shaft. The gear should move easily.
4.5.3.3 With gyro caged as in 4.5.3.2, apply 115 volts, 400 Hz, 3 phase
to pins A-B-C of P201. The gyro must stay caged as specified in 3.3.1.8.
4.5.3.4 With the turntable rotating at a speed up to one rpm, remove
the caging voltage (pins M-N and P of P201). The gyro must uncage as
specified in 3.3.1.9. The servomotor brake should be locked. Check
that it is by attempting to manually move the gear meshed with the servo-
motor shaft. There should be considerable resistance to moving. (Ref:
Holding torque of brake equals 4 oz-in.)
4.5.3.5 Caging current. To check the caging current as set forth in
3.3.1.3:
4.5.3.5.1 Connect the dc ammeter (4.5.2.8) in the 26 volt dc line.
4.5.3.5.2 Cage the gyro by applying 23 volts dc maximum to pins M-P of
P201, with pin M negative. The jumper from pin M to N, applied in 4.5.3.2,
should be removed prior to making measurements, Reconnect the jumper after
this test and leave it connected until 4.5.3.10.1 except during tests of
4.5.3.7 where the jumper is temporarily removed.
4.5.3.5.3 The current shall be 3.4 plus or minus 1.1 amperes while the
gyro gimbals are being caged. The current shall drop to 1.4 plus or minus
0.3 amperes when the gyro has caged.
4.5.3.5.4 Using an ohmmeter, monitor continuity between pins P and R
of P201, and apply 23 volts dc to pin P(+) and M(-) of P201. There shall
be no continuity until the gyro is in the fully caged position, at which
time continuity shall exist.
4.5.3.6 Zeroing.
To check the electrical zeroing as set forth in 3.3.2.1:
4.5.3.6.1 Mount the gyro with the flat cover (NAVORD Drawing 859711)
down on the gyro test stand (4.5.2.2.1).
4.5.3.6.2 Cage the gyro by applying 26 volts dc to pins M-P of P201, with
pin M negative.
4.5.3.6.3 Start the gyro by applying 115 volts, 400 Hz, 3 phase to pins
A-B-C of P201 (phase A to pin A, phase B to pin B, phase C to pin C).
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