Voith Torque Converter
Starting System for Gas Turbines
Variable-Speed Drives
We are the experts in hydrodynamic variable-speed drives at Voith Turbo.
Voith Turbo, the specialist for hydrodynamic drive, coupling and braking systems for road,
rail and industrial applications, as well as for ship propulsion systems, is a Group Division
of Voith GmbH.
Voith sets standards in the markets energy, oil & gas, paper, raw materials and transporta­
tion & automotive. Founded in 1867, Voith employs almost 40 000 people, generates Euro
5.2 billion in sales, operates in about 50 countries around the world and is today one of the
biggest family-owned companies in Europe.
Reliability & Availability:
Choosing the right system is important
Gas turbines are often started several times a day. Choosing the
right starting system will affect the start-up reliability of the gas
turbine. Voith supplies torque converters to all leading gas tur­
bine manufacturers and their licensees, to start gas turbines
ranging in power from 20 to 270 MW.
The combination of an induction
motor with a Voith torque converter
is synonymous with trouble free
start-ups, high reliability, and long
service life. More than 3 500 gas
turbine starters worldwide is out­
stand­ing evidence of our experience
and know-how in this area.
We believe no other starting system
or method equals the reliability and
availability of the Voith torque con­
verter starting system. Our excep­
tionally high MTBF (mean time be­
tween failure) leads to a statistical
reliability of 99.97 %. We also know
of no other starting system that
T
matches the 35-year design life of
the Voith torque converter; and this
comes with a guaranteed availability
of parts and service matching the
life of our machines. The compact
and rigid design offers trouble free
operation while maintenance ex­pen­
ses are at a minimum.
TC
Starter System
Generator
Gas Turbine
2
Torque converter
benefits, function and design
Basic design hydrodynamic torque converter
The benefits
n Voith torque converters are designed and built to meet customer
requirements. No other torque converter manufacturer offers this
Guide vanes
(adjustable)
service.
n Torsional vibration dampening and shock free power transmission;
consequently, no stress applied to connected equipment thus de-
Pump
wheel
Turbine
wheel
livering long service life.
n “No-load starting” condition on the starting motor by decoupling
the motor from the load through the “working oil shut-off valve”
feature.
n Low maintenance expenses.
n The Voith torque converter decouples the starting motor from the
gas turbine train during gas turbine operation without the need for
a mechanical clutch through our exclusive “working oil shut-off
valve” feature.
n Smooth and stepless output speed and torque adjustment of the
torque converter.
The heart of Voith’s hydrodynamic
torque converter is its hydraulic circuit; consisting of a pump, turbine,
and a guide wheel with adjustable
guide vanes (see picture above
right). This is combined in a common housing filled with hydraulic oil.
The mechanical energy of the motor
is converted into hydraulic energy
through the pump wheel. In the
turbine wheel the same hydraulic
energy is converted back into mechanical energy and transmitted to the
gas turbine / generator shaft. The
3
adjustable vanes of the guide wheel
regulate the mass flow in the circuit.
At closed guide vanes (small mass
flow) the power transmission is at
its minimum. With the guide vanes
completely open (large mass flow),
the power transmission is at its
maximum. Commonly, a constant
speed driver such as an induction
motor or a diesel engine drives the
pump wheel (input shaft of the
torque converter).
Because of the change in mass flow
(due to the adjustable guide vanes)
the turbine wheels’ speed is variable and can be adjusted to match
the various operating points of the
gas turbine.
At low speed, the turbine develops
its highest torque. With increasing
turbine speed, output torque decreases.
TT : Turbine torque
TP : Pump torque
h :Efficiency
1 : Turbine wheel
2 : Pump wheel
3 : Mass flow (oil)
TT
TP
h
Typical gas turbine start-up curve
Typical gas turbine start-up curve
Typical high speed setting
Typical low speed setting
TT
h
Using a multi-position guide
vane actuator, multiple hold
points and acceleration speeds
can easily be part of the
control logic.
TP
1
nT = 0
nT = nTmax
1Breakaway
2Unfired
resistance
3 Purge point
(air exchange)
4 Firing speed
5Acceleration
resistance to
self­sustained
speed
6Self-sustained
speed
4
3
1
=nT
ax
m
n T=
n opt
3
2
Depending on the design of the tur­
bine wheel the output torque at the
break-away (nT = 0) point is two to
ten times that of the pump (input)
torque. The guide vanes absorb the
torque differential between the tur­
bine (output) and the pump (input)
and transfer it to the foundation.
2
nT= 0
Torque
nT
5
6
0 %
Speed
By placing the guide vanes up­
stream of the pump wheel, the
torque requirement of the pump
(­input) remains constant at a given
guide vane setting, independent of
the load on the turbine (output). That
means an overload of the driver
(motor or engine) is not possible
through the hydraulic circuit. When
the hydraulic fluid is removed from
the torque converter circuit, the
pump (input) is “uncoupled” from the
turbine (output) and consequently,
the starter motor or engine is dis­
connected from the gas turbine.
4
Typical starter system P&I diagram
1
2
3
4
2
1
M
5
R
5
6
7
8
9
10
11
6
3
4
T
8
10
M
Torque converter
Torque converter housing
Fill and drain valve
Control valve
(Filling and draining)
Guide vane adjustment
Orifice plate
Working oil supply
Lube oil and cooling oil supply
Working oil return
Lube oil and cooling oil return
Lube oil tank of gas turbine
7
9
10
M
11
Through its characteristic of high
torque at low output speed, the
torque converter is the ideal gas
­turbine starter. With the abundant
acceleration torque available, the
gas turbine can be quickly accele­
rated to and above its self-sustained
speed, an important requirement of
the state-of-the-art, high tempe­
rature gas turbines.
Start Up
Other Functions
n Break-away of the gas turbine
through the torque converter or
the integral turning gear
n Acceleration to purge speed
n Acceleration to firing speed
n Assisting the gas turbine to and
above self sustained speed
n Uncoupling the starting system
from the gas turbine
n Turning the gas turbine by means
of the integral turning gear for
slow-roll functions
n Indexing the gas turbine for
inspections
n Fast spin-cooling of the gas turbine for rapid maintenance availability
n Extended gas turbine water-wash
cycles
5
Torque converter
power chart
Power chart
600
●Torque converter
for gas turbine
starting
400
200
▲Torque converter
in pump storage
power plants
100
40
20
Converter input power PP in MW
10
4
2
1
0.4
400
600
1 000
2 000
4 000
Converter input speed nP in rpm
Power versus input speed chart of exiting torque converters
6
6 000 8 000
Torque converter Model EL..Y
the classic design
Torque / speed characteristics
nP = constant
4.0
3.5
3.0
1.0
100 %
75 %
50 %
25 %
0%
0.5
MP
Lx =
Lx =
Lx =
Lx =
Lx =
2.5
0
Lx :
TP :
TT :
nP :
nT :
2.0
1.5
Guide vanes open
Input torque
Output torque
Input speed
Output speed
1.0
TT / TP
0.5
The model EL..Y with its single
stage turbine offers a torque multiplication factor of 4. Its balance of
features and torque characteristics
in combination with an integral turning gear makes it the ideal starter
for a broad range of gas turbines.
With the powerful hydraulic guide
vane system, controlled by solenoid
valves or an electric actuator, the
various operating points of the gas
turbine are easily obtained. When
combining the actuator with a
4-20 mA feedback system, the
0
0
0.2
nT / nP
0.6
torque converter becomes a true
variable speed drive with peak precision. The hydraulic fluid for the
torque converter can be supplied by
the gas turbine lube-oil system or
through a complete packaged starter
version including an oil reservoir system as available from VoithTurbo.
Examples of other options for turning the gas turbine are: Installing a
“pony” motor at the ODE of the
starting motor or installing a separate turning gear.
1.0
Selection of EL..Y
Starter Model EL 7,5 YFG 2.2 EL 10 YFG 6.5 EL 10,5 YG 10
Max. Input
power (kW)
2 200 1 270 6 500 3 700 10 000 5 800
Input
speed (rpm)
3 600 3 000 3 600 3 000 3 600 3 000
7
1
6
5
3
2 12
11
4
6
13
14
Simplified longitudinal section
of torque converter
Type EL 10 YFG 6.5
1
2
3
4
5
6
7
8
9
10
11
12
13
14
10
Input shaft
Pump wheel
Turbine wheel
Output shaft
Adjustable guide vanes
Adjusting mechanism
Filling and draining valve
Working oil supply
Working oil return
Lube oil return
Axial bearing
Radial bearing
Hydraulic cylinder
Guide vane actuator
10
9
Type EL 7,5 YFG 2.2
Type EL 10,5 YG 10
852
1880
475
650
Ø119
Ø80
650
Ø100
Ø160
1100
Type EL 10 YFG 6.5
Ø180
8
Ø110
7
880
323
360
690
1651
900
174
600
1164
720
540
357
1260
2150
Dimensions in mm
8
Torque converter Model EL..Z
the mighty one
We call it the mighty one because,
with its double stage turbine, it
offers a torque multiplication factor
of 10! It is used in applications with
high break-away torque. For vari­
ous operation points of the gas tur­
bine, the guide vane adjustment is
equipp­ed, in this case, with an elec­­­
tric actuator. The hydraulic fluid for
the torque converter can be sup­
plied by the gas turbine lube-oil-sys­
tem or through a complete pack­ag­
ed starter version including an oil
reservoir system as available from
Voith Turbo. By activating a simple
solenoid valve the torque converter
operating fluid is emptied from the
torque con­verter circuit and thus,
uncouples the starting system from
the gas turbine. Turning can be
done using an integral or separate
turning gear or a pony motor.
Torque / speed characteristics
nP = constant
10
1.0
9
Lx =100 %
Lx = 75 %
Lx = 50 %
Lx = 25 %
Lx = 0 %
7
6
0.5
TP
8
Lx : Guide vanes open
TP : Input torque
TT : Output torque
nP : Input speed
nT : Output speed
5
4
3
2
TT / TP
1
9
0
0
0
nT / nP
0.2
0.4
0.6
0.8
Selection of EL..Z
Starter Model
Type EL 10 ZFG
1092
EL 10 ZFG
1 800
Input speed (rpm)
3 000
111.8
555
Ø127
1485
Ø82
Max. Input power (kW)
720
864
Dimensions in mm
1
6
5
3
2
4
6
Simplified longitudinal section
of torque converter
Type EL 10 ZFG
1
2
3
4
5
6
7
8
9
10
Input shaft
Pump wheel
Turbine wheel
Output shaft
Adjustable guide vanes
Adjusting mechanism
Filling and draining valve
Working oil supply
Working oil return
Lube and cooling oil
return
10
7
8
9
10
Torque converter Model EL..
where power meets speed
Torque / speed characteristics
2.00
1.75
1.50
1.25
Lx =100 %
Lx = 75 %
Lx = 50 %
Lx = 25 %
Lx = 0 %
TT
TT / TP
0.25
0
TP
1.00
0.75
0.50
1.00
0.75
0.50
0.25
0
0
0.2
nT / nP
0.4
0.6
11
The hydraulic fluid for the torque
con­verter can be supplied by the gas
turbine lube-oil system or through a
complete packaged starter version
including an oil reservoir system as
available from Voith Turbo.
Turning can be done using an inte­
gral or separate turning gear or a
pony motor.
1.0
1.2
1.4
TP
Lx : Guide vanes open
TP : Input torque
TT : Output torque
With its single stage turbine and its
torque multiplication factor of ap­
proximately 2, the EL.. model offers
over-synchronous output speed.
With the powerful hydraulic guide
vane system, controlled by solenoid
valves or an electric actu­ator, the
various operating points of the gas
turbine are easily obtained. The ro­
bust, modular housing is designed
for various torque con­verter sizes
as well as other torque converter
types.
0.8
nP : Input speed
nT : Output speed
Selection of EL..
Starter Model
EL 9 G 6.0
Max. Input power (kW)
6 000
3 400
Input speed (rpm)
3 600
3 000
Turning speed (rpm)
–
–
Breakaway torque (Nm)
–
–
1
6 5 3
2
4
10
7
8
7
6
9
Simplified longitudinal
section of torque converter
Type EL 9 G 6.0
1
2
3
4
5
6
7
8
9
10
11
12
Input shaft
Pump wheel
Turbine wheel
Output shaft
Adjustable guide vanes
Adjusting mechanism
Hydraulic cylinder for
guide vane adjusting
Guide vane actuator
Housing
Fill and drain valve
Operating oil supply
Operating oil return
11
12
2.2
50 000
86 000
1945
3.0
650
3 600
Ø180
3 600
Ø119
7 500
1895
6 000
650
EL 10 GTM
7.5-86
Ø100
EL 9 GTM
6.0-50
Type EL 10 GTM 7.5-86
Ø119
Type EL 9 G 6.0
337
1006
1700
1260
357
880
1700
540
1260
1195
Dimensions in mm
12
Torque converter Model EL..YGTM
with integral continuous turning gear
Like many of Voiths’ torque converters, this powerful unit is equipped
with an integrated turning gear con­
nected to the output shaft with an
over-running clutch. Among the ad­
vantages of this design are space
savings and reduced cost through
the elimination of an additional coup­
ling and subsequently, reduced as­
sem­bly and alignment work. The
turn­ing gear is designed for long-life
with emphasis on high break-away
torque and long periods of lowspeed turning over the design life of
35 years. With this modular design,
a large number of system combin­
ations are available (different turning
gear and torque converter sizes)
per­mitting a high degree of customiz­
ation. A large number of this model
torque converter are in oper­ation
world­wide with integrated turn­ing
gears from 3 600 ft-lb (5 000 Nm) to
80 000 ft-lb (110 000 Nm).
The turning gears are available with
either AC or DC drive motors. In
add­ition, an electro-pneumatic turn­
ing device is available for con­nection
to the turning gear drive motor ac­
ces­sory shaft for ultra-slow indexing
of the gas turbine. The same turning
gears are also avail­able as stand
alone units.
Simplified longitudinal section
of torque converter with integral
turning gear
Type EL 9 YGTM 4.0-86
1
2
3
4
5
6
7
8
9
10
11
12
13
14
13
Input shaft
Output shaft
Pump wheel
Turbine wheel
Adjustable guide vanes
Housing
Filling and draining valve
Control valve for filling and
draining
Working oil supply
Working oil return
Overrunning clutch
Worm gear
Electric motor
Bevel gear
Selection of EL..YGTM
Max. Input power (kW)
4 000
10 000
Input speed (rpm)
3 600
3 600
2.4
6.0
86 000
110 000
540
Turning speed (rpm)
1150
1222
EL 10,5 YGTM 10-110
Ø180
EL 9 YGTM 4.0-86
Ø100
Starter Model
Type EL 9 YGTM 4.0-86
Breakaway
torque (Nm)
261.4
680
597.6
830
1891
Dimensions in mm
1
8
9
5
4
7 10
3
6
2
12 11
2
12 11
13
14
14
Torque converter EL..ZGTM
with integral hydraulic turning device
Simplified longitudinal section
of torque converter with integral
turning device
Type EL 7,5 ZGTM
1
2
3
4
5
6
7
8
9
10
11
12
13
This Voith torque converter with integrated hydraulic turning device is a
well-proven design with hundreds of
installations worldwide. Hydraulic
cylinders produce the output torque,
which is transmitted to the output
shaft via an overrunning clutch. With
each forward piston stroke, the gas
turbine is turned 45 degrees.
15
Input shaft
Output shaft
Pump wheel
Turbine wheel
Adjustable guide vanes
Housing
Filling and draining valve
Control valve for filling and
draining
Working oil supply
Working oil return
Overrunning clutch
Return stroke
piston / cylinder
Working stroke
piston / cylinder
With its double stage turbine the
torque converter offers a torque
multiplication factor of 10. For the
various operating points of the gas
turbine, the guide vane adjustment
system is equipped, in this case,
with an electric actuator with various limit and position switches.
5
4
9
11
2
13
11
10
7
12
EL 10 ZGTM-46
Max. Input power (kW)
1 000
1 800
Input speed (rpm)
3 600
3 000
45° intermittent
45° intermittent
35 000
46 000
Turning speed (rpm)
Breakaway Torque (Nm)
475
EL 7,5 ZGTM
1009
Type EL 7,5 ZGTM
Selection of EL..ZGTM
Starter Model
13
Ø80
8
3 6
Ø119
1
108
600
251.5
720
1340
Dimensions in mm
16
Torque converter Type E.. with fixed guide vanes
the compact one
For gas turbines with a power of up
to 45 MW, torque converters with
fixed guide vanes are available and
in operation in a large international
fleet. The design is purposely built
for high reliability and has a proven
avail­ability, superior to other types of
starters. The output speed of this unit
is controllable using a pressure re­
duction valve. Optionally, a hydraulic
turning device can be integrated into
this torque converter. Economical
savings are achieved through the
com­pact and simple design. With its
integral gear step, this torque conver­
ter can be easily matched to any gas
turbine speed requirements. For star­
ters, where a diesel engine is used
instead of electric starting motor, the
torque converter is ideally suited to
the diesel motor characteristic and
offers a no-load engine start.
Selection of E..
5
4
3
2
T
1
0
TT
TP
0 0.2 0.4 0.6 0.8 1.0 1.2
nT / nP
nP = constant
TP : Input torque
TT : Output torque
17
Starter Model
E 5 WAT
E 6 WAT
E 6 YAT
E 7 WAT
E7W
E7Y
E8W
Max. Input power (kW)
280 / 300
450
450
460 / 460
700
700
700
Input speed (rpm)
3 000 / 3 600
3 000
3 600
2 300 / 2 100
3 000
3 600
2 100
Turning speed (rpm)
45°
intermittent
45°
intermittent
45°
intermittent
45°
intermittent
–
–
–
11 000
11 000
11 000
11 000
–
–
–
Breakaway
torque (Nm)
P&I diagram of Type E 7 WAT
1
4 2
3
5 6
7
5
nT
nP
R
Type E 7 WAT
6
1 Input shaft with
connecting
coupling
2 Pump wheel
3 Turbine wheel
4 Fixed guide vanes
5 Gear stage
6 Output shaft
7 Hydrostatic turning
device
8 Working oil supply
9 Working oil return
1
4
na
3
2
T
Simplified longitudinal section of
torque converter
1
2
3
4
Torque converter
Oil pump
Relief valve
Helical gear
stage
5Hydrostatic
turning device
6Overrunning
clutch
Type E 6 WAT
8
9
Type E 7 W without turning device
1092
50.8
111.8
720
Ø78.3
Ø620
Ø447.7
Ø352.48
Ø447.7
Ø352.48
Ø82
Ø127
74
870
Dimensions in mm
18
Packaged Starter
a complete-system solution
Schematic diagram for oil circuit
of El 9 G 6.0 Package
1
2
3
4
5
6
7
8
9
10
11
12
13
Torque converter
Torque converter housing
Starting motor
Control valve for guide vane
position
Guide vane actuator
Transducer
Filter for control oil
Filling and draining valve
Thermocouples
Cooling oil
Indicator for guide vane
position
Working oil pump
Pressure gauge lube oil
pressure
Voith engineers configure gas turbine starting packages specifically
for your gas turbines. The table shows examples of starters in world­
wide operation. The Voith engineers are eager to design and offer a
system for your requirements.
Gas Turbine Starters
GT Starter
Model
EL 6,8 YFG
EL 6,8 YFG
1 076
1 005
1 200
2 500
2 146
2 500
Power (kW)
800
750
896
1 865
1 600
Speed (rpm)
3 600
3 000
3 600
3 600
Turning
speed (rpm)
–
–
45°
intermittent
2.4
Breakaway
Torque
–
–
–
–
35 000 Nm 86 000 Nm 36 000 Nm 46 000 Nm 110 000 Nm
25 800 ft-lbs 63 400 ft-lbs 26 500 ft-lbs 33 900 ft-lbs 81 100 ft-lbs
Cranking (HP)
19
EL 7,5 ZGTM EL 7,5 YGTM EL 7,5 YGTM EL 7,5 YGTM EL 10 YGTM
2.2-86
2.2-36
2.2-46
6.5-110
EL 9 G 6.0
EL 9 G 6.0
EL 9 GTM
6.0-50
5 000
3 755
4 025
4 025
1 895
3 700
2 800
3 000
3 000
3 600
3 600
3 000
3 000
3 600
3 600
2.3
2.3
3.0
–
–
3.0
–
–
–
–
50 000 Nm
36 800 ft-lbs
Torque converter, motor, and all re­
quired accessory equipment are fac­
tory mounted on a common base.
For more demanding requirements
such as retro-fitting to older gas
turbines, the design can include an
integral oil tank for a self contained,
pack­aged starter. An optionally avail­
able, onboard PLC system controls
the various phases of the starting se­
quence. With this all-­inclusive solu­
tion, site assembly, alignment, and
commissioning time is greatly reduc­
ed. The components of the packaged
starting system are ­select­ed to com­
pli­ment each other, achiev­ing an eco­
nomical and space consc­ious design.
Due to the torque con­verter charac­
ter­istic, the driver can be designed
as a true starting motor. This means
the driver (motor) can be used above
its continuous ­rating during the short
start-up of the gas turbine. This re­
sults in a smaller, space saving, and
economical motor.
13
2
10
3
12
1
9
8
4
11
6
7
5
Type EL 9 G 6.0
12 874
7 500
9 600
3 600
3 600
2.2
6.0
86 000 Nm
63 400 ft-lbs
110 000 Nm
81 100 ft-lbs
1700
1876
10 060
2530
1651
EL 10,5 YGTM
10-110
2986
EL 10 GTM
7.5-86
366
3505
6180
Dimensions in mm
20
Voith Turbo GmbH & Co. KG
Variable-Speed Drives
Voithstr. 1
74564 Crailsheim, Germany
Tel.+49 7951 32-261
Fax+49 7951 32-650
vs.drives@voith.com
www.voithturbo.com/variable-speed
cr228en, S&F-aik / SVG, 1.2011, 2 000. Dimensions and illustrations without obligation. Subject to modifications.
Voith Turbo Inc.
25 Winship Road
York, PA 17402, USA
Tel.+1 717 767-3200
Fax+1 717 767-3210
VTI-Information@voith.com
www.usa.voithturbo.com