Seakeeper 7000 GYRO User manual

DOCUMENT # 90021, REV 4
MAR 2009
MODEL 7000 GYRO
OPERATION MANUAL
P.O. BOX 999
14528 SOUTH SOLOMONS ISLAND ROAD.
SOLOMONS, MARYLAND, 20688, U.S.A
PHONE: [phone]
FAX: [phone]
E-MAIL: [e-mail]

DOCUMENT # 90021, REV 4
MODEL 7000 GYRO
OPERATION MANUAL
MAR09
Contents:
Section 1 – System Overview
Section 2 – System Operation
Section 3 – Power Failures, Alarms, and Troubleshooting
Section 4 – Maintenance
Section 5 – Warranty, Limit of Liability, Property Rights
Appendix A – Model 7000 Gyro Specs and Summary
Appendix B – Technical Drawings
P.O. BOX 999
14528 SOUTH SOLOMONS ISLAND ROAD.
SOLOMONS, MARYLAND, 20688, U.S.A
PHONE: [phone]
FAX: [phone]
E-MAIL: customer[email protected]om

DOCUMENT # 90021, REV 4
MAR 2009
MODEL 7000 GYRO
OPERATION MANUAL
SECTION 1 SYSTEM OVERVIEW
P.O. BOX 999
14528 SOUTH SOLOMONS ISLAND ROAD.
SOLOMONS, MARYLAND, 20688, U.S.A
PHONE: [phone]
FAX: [phone]
E-MAIL: [e-mail]

DOCUMENT # 90021, REV 4 MODEL 7000 GYRO OPERATION MANUAL-MAR09
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1SYSTEM OVERVIEW
The Seakeeper Model 7000 Gyro uses gyroscopic principals to reduce boat roll motions in waves
and wakes independent of boat speed. One Model 7000 Gyro will reduce the roll motions of a
boat that displaces 15 to 25 tons. Boats with higher displacement typically require multiple gyros
to provide good roll reduction. In multiple gyro installations, the gyros operate independent of
each other and therefore this manual only discusses operation of a single unit.
A Model 7000 Gyro consists of a gyro assembly, gyro control junction box, motor drive junction
box, network connection boxes (2), and operator display and keypad. The following pictorial
diagram illustrates the interconnection of these components and their interface with the boat.

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Technical specifications provided in Appendix A list the power consumption, total weight, and
dimensions of the major components. Gyroscopic principals that apply to boat roll control are
discussed on Seakeeper’s web site at www.seakeeper.com The Seakeeper web site also contains
videos of gyro operation and videos of several different boats operating in waves with the Model
7000 Gyro on and off. It is recommended that the reader play these videos prior to reading the
remainder of this manual.
The gyro’s gimbal angle and the gyro’s rate of rotation about the gimbal axis (termed precession
rate) play an important role in its operation. These parameters are illustrated in the following
figures. At zero degree gimbal angle, the gyro is vertical; it can precess a maximum of +/- 60
degrees about this position. The amount of torque that the gyro exerts on a boat’s hull to counter
the wave induced roll is directly proportional to the precession rate and the trigonometric sine of
the gimbal angle. The further the gyro is from vertical (zero degrees) the lower the anti-roll
torque. Blue arrows in the figures illustrate the direction of the forces that the gyro’s exerts on the
boat’s hull to damp roll motion.

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Seakeeper gyro precession is actively controlled by an electronic controller and a hydraulic brake
throughout each roll cycle so the gyro supplies the maximum anti-roll torque and does not make
mechanical contact with hard stops that limit the maximum gimbal angle travel to +/- 60o.
!
There is a large torque about the gimbal axis when the gyro is precessing.
Therefore, the gyro should be in-housed in a compartment or installed in a
cage so personnel cannot ever come into contact with the gyro while it is
precessing. If it is ever necessary to touch the gyro while the flywheel is
spinning, the Lock button on the Keypad must be depressed to stop the gyro
from precessing. Gyro maintenance should not be attempted unless the gyro
is locked and the flywheel has stopped spinning.

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1.1 GYRO ASSEMBLY
The gyro assembly consists of a flywheel housed in a cast aluminum vacuum-tight sphere. The
flywheel spins about a vertical axis and is supported by upper and lower pairs of bearings. A DC
brushless motor mounted inside the enclosure spins the flywheel at high speed.
The enclosure is fastened to two gimbal shafts that are supported by gimbal bearings on either
side. These shafts establish an athwartship gimbal axis about which the flywheel and enclosure
precess or rotate up to +/- 60 degrees during operation. Each of the gimbal bearings is supported
by a saddle beam which is bonded to the hull structure. These beams transfer the loads that the
gyro produces to the hull structure.
An active hydraulic brake mechanism is located on gyro assembly to regulate the gyro’s
precession motions about the gimbal shaft. It includes two hydraulic cylinders mounted on the
port saddle beam and a hydraulic manifold on the starboard saddle beam.
A coolant pump, heat exchanger, accumulator, and thermostatic mixing valve are located on a
cross brace at the back of the gyro that connects the port and starboard saddle beams. A
glycol/water mix is circulated thru a closed loop to the end caps of the spherical enclosure,
hydraulic manifold and motor drive box to remove heat.

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1.2 KEYPAD AND DISPLAY
The keypad and display shown below are the user interface to the Model 7000 Gyro and should
be mounted at the primary helm station. They are used to start, operate, monitor and shutdown the
Gyro. Sensors, alarms and shutdowns are provided to allow unattended operation however the
gyro is a high-speed machine and special attention should be paid to vibration and noise as the first
hint of a mechanical problem may show this way.
The display provides the user with status information such as bearing, motor and drive
temperatures, motor current, vacuum pressure, boat motion and gyro gimbal angle. The display
also provides information in the event of an alarm or shutdown.

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1.3 MOTOR DRIVE J-BOX
The Motor Drive Junction Box contains the electronic components that take 185-240 VAC at
50/60 Hz from the boat’s generator or shore power and supply current to the flywheel motor
according to commands from the controller in the Gyro Control Junction Box. The glycol/water
mix that cools the gyro is also circulated through the two cold plates on the back of the Motor
Drive Junction Box as shown in the photos below.
The Motor Drive Junction Box contains high voltage electronics and the
cover should not be removed while the flywheel is spinning except by an
authorized technician. This high voltage exists even if the flywheel is
coasting down and the supply voltage has been shut off.

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1.4 GYRO CONTROL JUNCTION BOX
The Gyro Control Junction Box contains a motion sensor package (MSP) and a controller module
that is programmed with the software that monitors and automatically regulates operation of the
gyro.
The motion sensor package contains rate sensors that measure the angular movements of the vessel
and accelerometers that measure the vertical and lateral boat movement.
The controller commands the motor speed and regulates the gyro’s precession rate and gimbal
angle by commands to a high response flow control valve in the brake circuit that increases or
decreases brake pressure.
The Gyro Control Junction Box must be mounted on the aft face of a transverse bulkhead so the
signs of the motion sensors are consistent with the orientation of the gyro.

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1.5 BRAKE
The brake mechanism consists of two hydraulic cylinders which are mounted on the port side
saddle beam and attach to a crank arm on the port gimbal shaft. The hydraulic cylinders are
plumbed to a manifold / valve assembly so when the gyro rotates about the gimbal axis, oil from
one side of each cylinder is pushed through the high response flow control valve into the same side
of the other cylinder. The gyro controller modulates how fast the oil can flow through the control
valve thus controlling the precession rate of the gyro.
The brake hydraulic circuit is a pre-charged closed loop – that is there is no pump, motor or
reservoir in the circuit. Accumulators are installed in the circuit so the precharge pressure does not
increase as the fluid temperature rises due to the braking action. Locking solenoids are installed in
the circuit to lock the gyro so it cannot precess if there is a leak in the circuit or there is a
mechanical problem with the gyro.
BRAKE CONTROL
VALVE
MANIFOLD
BRAKE
HYDRAULIC
CYLINDER
GIMBAL
ANGLE
SENSOR

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1.6 COOLING
The cooling circuit is a closed loop that supplies a glycol/water (75% distilled water and 25%
glycol) mix to:
•The gyro sphere end caps to remove heat from the flywheel bearings
•The brake manifold to remove heat from the brake hydraulic circuit
•The motor drive box to remove heat from the drive electronics
The heated fluid then passes through a thermostatic mixing valve before bypassing or flowing
through a heat exchanger that has sea water on the cold side. The circuit also contains an
expansion tank so pressure does not increase as the coolant heats up.
MIXING
VALVE
EXPANSION
TANK
HEAT
EXCHANGER
SEA WATER
INLET/OUTLET
CIRCULATION
PUMP

DOCUMENT # 90021, REV 4
MAR 2009
MODEL 7000 GYRO
OPERATION MANUAL
SECTION 2 SYSTEM OPERATION
P.O. BOX 999
14528 SOUTH SOLOMONS ISLAND ROAD.
SOLOMONS, MARYLAND, 20688, U.S.A
PHONE: [phone]
FAX: [phone]
E-MAIL: [e-mail]

DOCUMENT # 90021, REV 4 MODEL 7000 GYRO OPERATION MANUAL-MAR09
Page 2of 8
2SYSTEM OPERATION
2.1 START-UP
•Make sure AC and DC power are available
•Turn “On” the boat’s AC and DC circuit breakers
that supply power to the gyro.
•Turn “On” the boat’s pump that supplies seawater
to the Gyro heat exchanger
•Verify that the “Lock” lamp is lit on the Gyro
Keypad
•Verify that no alarms are present. Alarms show
on the RPM Page of the Gyro Display. Depress
the Menu button on the Display to change pages.
2.2 RUN – STANDBY – KEYPAD OPERATION
If the boat is going to be moved and the Gyro is not
•Depress Run
required for stabilization:
•Depress Standby
These two actions increase Gyro speed to 1000 rpm to
lubricate the flywheel’s high-speed bearings when the
vessel is underway and the Gyro is not required for roll
stabilization. The Gyro uses less than 150 watts of AC
power in this mode. The Standby Button will illuminate
and the Run button will flash until the flywheel reaches
1000 rpm and then change to constant illumination. The
Lock button will be illuminate indicating that the Gyro
is locked and cannot precess.

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2.3 RUN – STANDBY – DISPLAY OPERATION
The RPM Page of the Gyro Display will indicate 1.0
KRPM once the flywheel reaches Standby speed.
The bearing, motor and drive temperatures, motor power
and vacuum pressure can be checked on other display
pages. Depress the Menu button to change pages.
2.4 RUN – STABILIZATION – KEYPAD OPERATION
If the Gyro is going to be used for stabilization at sea or
at anchor and full capability is required:
•Depress Run
This action increases flywheel speed to 9700 rpm for
stabilization. It takes approximately 45-60 minutes for
the flywheel to reach 9700 rpm. The Run button will
flash until the flywheel reaches 7500 rpm and then turn
steady indicating that stabilization can be activated. The
Lock button will be illuminated indicating the Gyro is
locked and cannot precess to stabilize the roll motion
until the Sea button is depressed.
!
If it is necessary to shutoff power to the flywheel
motor and start slowing down the flywheel for any
reason, depress Run a second time and the light will
go out indicating the command has been accepted.
The Lock button should also be depressed to stop
precession. It takes approximately 1-1/2 hour for the
speed to drop from 9700 rpm to 5000 rpm and 4+
hours for the speed to drop 9700 rpm to zero rpm.

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To turn on stabilization, the rpm must be above 7500
.
•Depress Sea
The Lock light will go out and the Sea button will
illuminate indicating that the Gyro is precessing and
stabilizing the boat’s roll motion. The Controller
increases the overall gain slowly; it takes 5-10 seconds
to reach full effectiveness.
!
If it is necessary to stop precession for any reason
depress the Lock button. The light on the Sea button
will go out and the light on the Lock button will
illuminate indicating that the Gyro is Locked. There
is still a very large torque about the Gyro’s gimbal
axis and no one should ever attempt to work on the
gyro until the flywheel has stopped spinning. In the
event, that the Gyro Controller has automatically
locked the gyro due to an alarm or failure, no attempt
should be made to bypass the alarm or automatic
Lock.
In some cases (such as on anchor at night) the sea
condition may be very calm and the Gyro is only
required to damp motions associated with light swell or
with the wakes from passing boats. In these situations,
the operator can Run the Gyro at 8000 rpm to reduce
gyro noise and power consumption without significantly
reducing performance (i.e., roll reduction).
When the operator first depresses the Run button on the
Keypad, the gyro will start accelerating to full speed
(9700 rpm). To reduce the Gyro’s speed to 8000 rpm,
go to the Speed Command page on the Gyro Display. If
it reads 9700 rpm depress the Down button to set the
speed command to 8000 rpm. If it reads 8000 rpm and
you want to go to 9700 rpm then depress the Up button
to increase the speed command to 9700 rpm.

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2.5 RUN – STABILIZATION – DISPLAY OPERATION
The Display has a number of individual screens. The
operator depresses the Menu button (not the Up and
Down buttons) to move from one screen to the next.
The RPM page on the Display will indicate 9.7KRPM
once the Gyro reaches full speed.
The ANGLE page on the Display indicates the gimbal
angle. It should be between +/- 50 degrees during
precession except when the boat is turning to port it
may slowly go as high as +/-60 degrees. This is normal.
The BEARING page on the Display indicates the
temperature of the upper outer, upper inner, lower outer
and lower inner bearings. Pressing the Up Button on
the Display reveals the bearings names. Bearing
numbers 1, 2, 3 and 4 correspond to Upper Outer,
Upper Inner, Lower Inner and Lower Outer locations on
the flywheel shaft respectively. The bearings typically
run 20oto 40oC hotter than the ambient sea water
depending on the sea state. The rougher the sea state,
the higher the bearing loads and the more heat they
generate.

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The Motor page on the Display indicates the temperatures and
current draw of the Motor that is spinning the flywheel. The
motor typically runs 20oC 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 15-20oC hotter than
the ambient sea condition during spin-up and 10-15oC
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.

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For example with the Gyro in Lock, the operator can take roll rate readings with the boat
in beam seas at zero speed for 5 minutes and get a quantitative measure of the boat’s
uncontrolled roll motions. If the operator repeats this test with the Gyro in Sea mode
then he or she has knows how much the gyro reduced the roll motions. A test like this
should be conducted for about 5 minutes which corresponds to roughly 100 roll cycles on
a typical 15 to 25 ton boat.
Active alarms are displayed on the RPM page directly
under the flywheel speed. If there is more than one
active alarm, the screen will cycle from one alarm to the
next alarm. The Gyro is designed for unattended
operation and therefore there is no audible alarm. If an
alarm is displayed the operator should check to see if
the Run light and the Sea light on the Keypad are still
illuminated. Most alarms will automatically Lock the
Gyro and remove the Run command which coasts the
flywheel motor.
The Alarm History page displays all alarms that have
occurred since the system was shipped from the factory.
The alarms are in chronological order starting with the
most recent. Only one alarm is displayed at a time –
depress the Down button to display each alarm in the
Alarm History file.
The Brake Service page is only used for servicing the
Gyro’s hydraulic brake as discussed in the Maintenance
section of this manual. It will display “Service Brake
Not Available” any time that the gyro is spinning.

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2.6 NORMAL SHUTDOWN
•Verify that no alarms are present on the Gyro
display
•Depress Lock (Lock lamp will illuminate in a few
seconds)
•Depress Run (Run lamp will go out and flywheel
will start to coast)
!
•It is important to keep both AC and DC power “on” so the boat’s seawater pump
and the gyro’s glycol pump are running until the flywheel coasts down to 5000
rpm. Seakeeper appreciates that this places an unusual requirement on the boat
operator as it takes 1.5 hours for the flywheel to coast down to 5000 rpm. The
flywheel bearings are still generating significant heat during the first half of the
coast down cycle and Seakeeper requests that this procedure be followed until we
gain more experience and can issue an updated operational instruction to reduce
the “power on” time during coast down.
•Turn “Off” the boat’s AC and DC circuit breakers that supply power to the Gyro.