Sperry Marine 4914-CA, Operation, Installation And Service Manual

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2. Observe the settling of the gyrosphere:
– The gyro motors will create a spinning noise which slowly but
constantly rises in pitch until the rotors reach their final speed.
– The follow-up system will turn the container quickly around the
gyrosphere until the optical pick off “locks” onto the motion of
the gyrosphere. From then on, the container will engage in a
slow oscillatory motion around the vertical, following the motion
of the gyrosphere.
– The amplitude and speed of this motion will steadily decrease
until the gyrosphere finally settles.
3. During the settling phase, periodically call up the gyrosphere data
sub-menu from the Service Setup 2 (code 610), to observe the gyro-
sphere current, see ”GYROSPHERE DATA” on page 8-22 in the
‘Service Setup 2 – Parameters´ submenu.
4. Check 20 minutes after power-up wether a considerable fall of the
gyrosphere current has occurred.
5. Check if after around 45 minutes after power-up whether the gyro-
sphere current has dropped below 320 mA.
6. If after around 45 minutes after the power-up, a gyrosphere current
above 320 mA is still displayed in the gyrosphere data sub-menu,
the value must be reconfirmed:
– Measure the gyrosphere current directly at the 1
Ω
gyro current
test resistor (R103) on the master PCB, location of the test resis-
tor (R103) shown in figure 5-1 on page 5-10.
7. In case the reconfirmed value for the gyrosphere current, directly
measured (true RMS) at the 1
Ω
gyro current test resistor (R103) on
the master PCB is in contrast under 320 mA, the gyrosphere current
Directly after power-up, the gyro-
sphere current should not exceed
550 mA. The current will gradually
fall while the gyrosphere settles.
TEMPERATURE 42
°
C
GYRO CURR 432 mA
PH BRIDGE 10 mV
GYROSHPERE DATA
kçíÉ
20 minutes after power-up a considerable fall of the gyrosphere current
should have occurred.
Within around 45 minutes after
power-up, the gyrosphere current
should have dropped below 320 mA.
TEMPERATURE 42
°
C
GYRO CURR 234 mA
PH BRIDGE 10 mV
GYROSHPERE DATA
kçíÉ The true operating value of the gyrosphere current can only be measured
(true RMS) at the 1
Ω
gyro current test resistor (R103) on the master PCB,
location shown in figure 5-1 on page 5-10.
kçíÉ The AC-voltage in mV across the test resistor (R103) equals the gyro-
sphere current in mA.