DOCUMENT # 90021, REV 4 MODEL 7000 GYRO OPERATION MANUAL-MAR09
Page
6
of
8
The Motor page on the Display indicates the temperatures and
current draw of the Motor that is spinning the flywheel. The
motor typically runs 20
o
C hotter than the bearings. Amp
readings represent the DC current command to the flywheel
motor not the AC line current.
The Motor current is 22 amps when the motor starts
spinning the flywheel. As it speeds up, the motor
current decreases so the gyro does not draw more than
2 kW. Once the flywheel reaches full speed, the
current typically drops back to less than 6 amps in
Lock or Sea modes without precession and is limited to
9 amps in Sea mode with precession.
The Drive/Enclosure page displays the temperature of
the power section of the electronics in the Motor Drive
Junction Box and the pressure inside the Gyro’s vacuum
tight spherical enclosure.
The Drive temperature is typically 15-20
o
C hotter than
the ambient sea condition during spin-up and 10-15
o
C
hotter than the seawater in the Lock and Sea modes.
The Enclosure gas pressure is typically between 5 and
15 Torr (or mmHg) at startup depending on the ambient
temperature. During operation, the gas pressure slowly
rises because various molecules trapped in and attached
to the surface of the enclosure and flywheel gain enough
energy to detach from the metal surfaces and fly around
in the gas. This pressure rise is completely normal.
The Gyro/Roll Rate page displays information about
the movement of the gyro and the motions of the boat.
It displays the standard deviation of the gimbal angle in
degrees, the precession rate in degrees/sec and the
boat’s roll rate in degrees/sec. This information is not
required to operate the Gyro however it is useful in
assessing performance.
