The MAAG Synchronizing Clutch Coupling Program and its ...

The MAAG Synchronizing
Clutch Coupling Program
and its Applications
Innovative Power Transmission

2
The MAAG Synchronizing Clutch Coupling Program
and its Applications
In 1960 MAAG decided to develop and
manufacture synchronizing clutch couplings.
After extensive research and design
work, including the testing of a proto type
on a special testbed, the first unit was sold
in 1964. Since then, continuous development
of this product has resulted in a
prod uct line that now enables us to offer
a range of different synchronizing clutch
couplings. All types can be supplied with
features tailored to the specific requirements
of the synchronizing clutch coupling
applications.
Synchronizing clutch couplings are required
in a wide range of application.
Marine Applications
• combined propulsion systems such as
CODOG, COGOG, CODAG, COGAG,
CODAD, etc.
• efficiency booster drives for diesel
engine propulsion
Power Generation
• generator drives
• peaking power stations
• air storage power stations
Energy Recovery, Combined Cycle
Technologies, Cogeneration and
others
• connecting expander turbines to main
drives in petrochemical plants
• blower drives in nuclear power stations
for use during starting sequence
• starting device for gas turbines
• automatic turning gears
Synchronizing clutch couplings are couplings
which engage and disengage automatically.
They are capable of automatic
engagement at any speed within the
operating range as soon as the driving
machine overruns the driven machine.
Basically the synchronizing clutch coupling
is a disengageable coupling equipped with
a synchronizing mechanism.
The synchronizing clutch coupling consists
of two main elements:
A) The gear coupling part for the power
transmission. This is the same as in a
standard tooth coupling, i. e. the external
coupling teeth are hardened and ground
with longitudinal corrections allowing for
angular misalignment.
B) The synchronizing mechanism detects
synchronism of both shafts and initiates
subsequently the engagement. This synchronizing
mechanism is an assembly consisting
mainly of a number of pawls and a
multiple notched ratchet wheel. Together
they act as a free wheel drive.

Today, RENK­MAAG offers three main
sychronizing clutch coupling lines.
Type MS Type DS Type HS
• The clutch engages
automatically when
the input shaft
overruns the output
shaft.
• Positive torque can
be transmitted.
• The clutch disengages
automatically
when the torque
becomes negative.
• After the «ENGAGE»
command is given,
the clutch engages
automatically when
the two shafts overrun
each other, irrespective
of direction.
• Positive and negative
torque can be transmitted.
• After the «FREE
WHEEL» command is
given, the clutch disengagesautomatically
when the torque
becomes negative.
Once disengaged, the
two shafts are free to
overrun each other.
• The clutch engages
automatically when
the input shaft
overruns the output
shaft.
• Positive and negative
torque can be transmitted.
• The clutch disengages
only upon
command.
1
The synchronizing mechanism is designed for unlimited operation of the clutch in
disengaged position at any speed difference between the input and output shafts.
2
The synchronizing mechanism is of relatively light but still robust construction.
Therefore, high angular accelerations at engagement are permissible.
3
The synchronizing mechanism plays no part whatever in power transmission. It is
simple, compact and incorporated into the coupling sleeve, suitable for high speed
operation.
4
Torque transmission is the same as in standard toothed couplings, combining
torsional rigidity with axial and angular flexibility.
5
Suitable for transmitting practically any torque at any speed for which toothed
couplings can be employed.
6
Angular and parallel misalignment of the shafts is easily accommodated by the
coupling components.
3

4
Each synchronizing clutch coupling can
also be supplied with a variety of distinctive
options. The diagram below gives some ex­
MS-R MS-S
amples of possible features combinations
for two of the designs, Type MS and Type
HS.
Synchronizing Clutch Coupling
MS
Basic Design
DS
Additional Features
MS-H HS-H
J
X
F
Q
E
T
A
HS
HS-N
R: locking mechanism
S: rigid when engaged
H: integrated fluid coupling
for start­up
N: engagement at low speed
J: electrical insulation
X: limited end float
F: isolating device (pawl free)
Q: quill shaft arrangement
E: encased
T: for turning gears
A: for starter drives

Applications for
MAAG Synchronizing Clutch Couplings
In light of the information on page 4, the
following information can be ob tained
from the type designation of a particular
synchronizing clutch coupling:
basic design:
M
H
S
S
M = mechanical automatic
disengagement
H = hydraulic disengagement
S = synchronizing
clutch coupling
coupling size
26
60 / 7
R
H
...
additional features
(see legend on the left)
...
...
...
coupling / synchronizer size
5

6
Marine Applications
Installation of a MAAG synchronizing clutch
coupling type HS­40­F in a MAAG marine
gearbox type DTA­260W CODOG.
The synchronizing clutch coupling is
mounted between the gas turbine and the
first reduction pinion shaft, whereas the
diesel engine is connected to the gearbox
through a friction clutch.
At cruising speed, the diesel engine is
clutched to the gearbox and the gas turbine
is stationary with the synchronizing
clutch coupling disengaged. If maximum
speed is demanded the gas turbine will
be started and accelerated. When the turbine
shaft overruns the primary pinion, the
clutch engages. The ship’s propulsion power
is now delivered by the gas turbine, the
Isolating device (manually operated)
Clutch coupling
Output (pinion shaft) Input (gas turbine)
diesel engine is disconnected and the gas
turbine accelerates further up to full speed.
When changing back to cruising speed,
the gas turbine will be decelerated, the
diesel engine started and clutched to the
gearbox as soon as the speed is within the
operating range of the diesel engine. After
the load has been transferred from the gas
turbine to the diesel engine, the disengage
signal is given to the synchronizing clutch
coupling, the clutch disengages and the
gas turbine, disconnected from the main
gear, runs down to standstill.
Diesel
engine
Friction
clutch
Gearbox
Synchronizing
clutch coupling
type HS­40­F
Gas turbine

Typical arrangement of two synchronizing
clutch couplings in CODOG marine gearbox.
The type MS­36­RF which connect/disconnect
the gas turbine from the main gear
train is equipped with a locking mechanism
and an isolating device (pawl free
posi tion). The other type MS­36­RQ to
connect/disconnect the diesel engine from
the main drive is of the quill shaft mounted
design.
The operating characteristics of this installation
are basically the same as the previous
application. However, because type
MS clutches are installed no disengaging
signal is needed to disengage the clutch.
After the power transfer has been accom­
Diesel
engine
Gearbox
Hydraulic
coupling
Synchronizing
clutch coupling
type MS­36­RQ
Synchronizing
clutch coupling
type MS­36­RF
Gas turbine
plished, the changeover is achieved by reducing
the speed of the driver to be shut
down.
A clutch is required in the diesel engine
drive train because the output members of
the hydraulic coupling cannot sustain the
higher speed in propulsion mode.
In the installation described here, each of
the clutches is equipped with a locking
mech anism. Prior to a propulsion mode
changeover the clutch to be disengaged
has to be unlocked. This is initiated by an
electric signal.
Diesel clutch in disengaged (quill shaft mounted) position
Output
(pinion shaft)
Output
(pinion shaft)
Spool
piece
Input
(diesel engine)
Coupling
sleeve
Turbine clutch in disengaged position
Input
(gas turbine)
Lube
oil feed
7

8
The diagram below shows an arrangement
for a CODAG marine propulsion system.
This system requires three synchronizing
clutches, 2 MS types and 1 DS type. The arrangement
combines a gas turbine with a
diesel engine.
Normally, a speed change gearset (gearbox
A) is required at the cruise diesel engine
when the booster is added to the drive
system to be operated in combined mode
(CODAG). This is necessary to prevent the
diesel engine overspeeding.
The gas turbine booster drive is clutched
to the main gearbox by an MS clutch (B).
The + sign indicates that the clutch engages
automatically when the turbine input speed
overruns the input pinion speed.
View of DS synchronizing clutch coupling
In cruising mode when the Diesel only is driving
clutch C and A (+ end) are engaged and locked,
clutch B and A (­ end) are disengaged. Torque is
transmitted by clutch C only.
In GT only driving mode clutch B and A (­ end)
are engaged and locked, clutch C and A (+ end)
are disengaged. Torque is transmitted by clutch B
only. Gearbox A is at standstill.
In CODAG mode, Diesel and GT driving, clutch A
(+ and – end) and B are engaged and locked,
clutch C is disengaged.
The diesel engine cruise drive is clutched to
the main gearbox by an MS clutch (C). The
+ sign again indicates the same functions
as above.
For both drivers to operate together, it is necessary
to transmit the power of the diesel
engine through a ratio matching gearset,
(gearbox A) such that the engine can operate
in its most efficient operating condition.
This requires a DS clutch (A) which is freewheeling
in either gas turbine only mode or
diesel engine only mode, and which is engaged
and locked (both the + and – ends)
when operating in CODAG mode. Clutches
B and C also have a locking capability in their
respective modes to prevent disengage ment
if negative torques are encountered during
normal propulsion mode operation.
Main Gearbox
Synchronizing
clutch coupling
type MS
bull gear
Gearbox A
Synchronizing
clutch coupling
type MS
Synchronizing
clutch coupling
type DS
Hydraulic
coupling
Gas
turbine
Diesel
engine

Power Generation
MAAG synchronizing clutch coupling type
HS­85 installed in a power plant between
the gas turbine and generator.
The generator is on line permanently. If
pow er is needed, the gas turbine is started
by its starting system and further accelerated
to full speed. When the gas turbine shaft
overruns the generator shaft, the clutch
engages and power is transmitted. When
pow er is no longer required, the gas turbine
power is reduced to approx. zero, and the
disengage signal is sent to the clutch, which
disengages immediately. The gas turbine
is shut down and the generator to rotate,
operating as a synchronous condenser.
Synchronizing
clutch coupling
type HS­85
Gas turbine Generator
Input
(gas turbine)
Spool piece with
synchronizing mechanism
Servo mechanism
Output
(generator)
9

10
MAAG synchronizing clutch coupling type
HS­85­H installed in a power plant between
gas turbine and generator.
As its designation indicates, this type
HS­85­H is combined with a fluid coupling.
This fluid coupling will be used to start the
gas turbine when the generator is working
as a synchronous condensor. The gener ator
rotates at synchronous speed, i. e. 3000
rpm, in the case of a 50 Hz grid, the clutch
coupling is disengaged and the gas turbine
is stationary.
If power is required from the gas turbine,
the turbine is accelerated by filling the fluid
coupling. Above a certain speed, the turbine
accelerates under its own power, after
which the fluid coupling is emptied. The
Synchronizing clutch coupling
type HS­85
Special frame
(mounted on site)
turbine accelerates further until it overruns
the generator. The clutch coupling engages
automatically. Power can now be transmitted
from the turbine to the generator.
This arrangement avoids the need for an expensive
separate starting device for the gas
turbine.
Fluid
coupling H
Synchronizing
clutch coupling
type HS­85­H
Gas turbine Integrated
fluid
coupling
Generator

This is an example of a synchronizing clutch
application in an air storage power plant.
The synchronizing clutch coupling type
MS­85­S is mounted between the gas
turbine (power turbine only) and the generator.
In this case the MS­type coupling
has the S­feature which means that the
cou pling will behave like a rigid coupling
when engaged.
Centrifugal
compressor
Disgengageable
coupling
Generator/
motor
Synchronizing
clutch coupling
type MS­85­S
Output
(generator/motor)
Gas Turbine
(power turbine
only)
Input
(gas turbine)
Exploded view of the type
MS­85­S synchronizing clutch coupling
11

12
Energy Recovery, Combined Cycle Technology,
Cogeneration
This shows a typical energy recovery application
for the type MS­14 synchronizing
clutch coupling in a compressor installation
where surplus process gases, instead
of being released by a valve, are used to
drive a gas expander. This gas expander is
cou pled to a centrifugal compressor via the
type MS­14 clutch. If no surplus process
gases are available, the gas expander is
automatically disconnected thus avoiding
windage losses in the gas expander.
Output coupling hub
with synchronizing mechanism
(centrifugal compressor)
Coupling assembly
Spacer
Coupling sleeve
Input coupling
hub (expander)
Steam
turbine
Synchronizing clutch
coupling type MS­14
Centrifugal
compressor
Gas
expander

This is a typical example of a synchronizing
clutch coupling application in the field of
combined cycle technology in a chemical
plant. Steam is generated by a conventional
boiler, which can be used for the process
technology or power generation. If steam
is available, the steam turbine will be
started and automatically coupled to the
generator.
In the original arrangement, without overrunning
clutch, cooling steam was required
to windmill the steam turbine (no power
generation by steam turbine). By installing
the clutch coupling the steam turbine can
be shut down, no cooling steam is re quired
and overall efficiency is considerably increased.
In this example installation, the
MS­36­J is electrically insulated and in­
Gas turbine Generator Steam turbine
Gearbox
Synchronizing
clutch coupling
type MS­36­J
stalled between the steam turbine and the
gener ator. In this particular case the synchronizing
clutch coupling was installed as
a replacement for a gear coupling.
Output coupling
hub with synchronizing
mechanism (generator)
Clutch assembly with mounting frame
Spacer
Input
coupling sleeve
(steam turbine)
13

14
Other Applications
Synchronizing Clutches for Automatic
Turning Gears Type MS-…-T
The MAAG synchronizing clutches for
turn ing gears are of simple construction,
suit able for turbomachinery installations,
and combine outstanding reliability with
high torque transmitting capacity.
The clutch automatically engages at the
instant the input speed tends to overtake
that of the output shaft. Conversely, the
clutch will automatically disengage when
the output shaft speed exceeds the speed
of the input shaft. A full range of turning
gear clutches is available.
Design principle of a MAAG free­standing
synchronizing clutch coupling
for high power transmission
(e. g. 131.5 MW/60 Hz or
125.0 MW/50 Hz)
Output shaft
Free-Standing Synchronizing
Clutch Couplings Type MS-…-E
The encased MAAG synchronizing clutch
couplings have been developed for installations
where the driving machine has
to be totally isolated for «on­site» maintenance
while the driven machine continues
to rotate. Typical applications for the
encased clutches are fan drives with two
driving machines.
The input and output shaft are each supported
by two amply dimensioned bearings.
The type MS­clutch is mounted inside
the casing between the two shafts. The
cas ing is of fabricated steel plates. Standard
fle xible couplings such as diaphragm couplings
can be used to connect the clutch
unit to the driving and driven machines.
Automatic turning gear clutch type
MS­8­T installed in gearbox between
turning gear and pinion shaft
MS clutch
Input shaft

Typical Examples of Applications
ANZAC CODOG gear system
on testbed
MAAG synchronizing clutch
type MS-76/E
ANZAC frigate
15

Customer Service / Spare Parts / Maintenance / Testbed
RENK-MAAG cares for the customer
during and after the sales: Our efficient
sales team is prepared to give
advice regarding new equipment
and original spare parts for couplings
and gearboxes of MAAG type.
On-site support is provided worldwide
for all MAAG-turbo and marine
gearboxes by our experienced and
certified field service engineers. Periodical
and/or preventive maintenance
assure the safe and reliable
operation of equipment. Our service
field engineers are at your disposal
for inspections and maintenance.
RENK-MAAG
is at your disposal
Production and other activities are
monitored by the internal quality
assurance system and in strict
compliance with ISO 9001 : 2008.
In case of need to fully refurbish or
revamp a gearbox, coupling or components
at our facility, we provide a
full range of support with the delivery
of a re-warranted unit.
New gearboxes and components
can thoroughly be tested applying
the latest technology in diagnostic
mon itoring equipment for vibration,
temperature and sound.
Test runs of refurbished gearboxes
are also concluded where verification
of repair work must be certified.
RENK-MAAG GmbH
Postfach 3068 • Sulzer-Allee 46 • CH-8404 Winterthur
Tel. +41 (0) 52 262 89 88 • Fax +41 (0) 52 262 89 89
info@renk-maag.ch • www.renk-maag.ch
Neuauflage Kü 09.2010 e