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.

2

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.

Reliability & Availability: Choosing the right system is important

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

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-

stand ing evidence of our experience

and know-how in this area.

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 ex pen-

ses are at a minimum.

Generator Gas TurbineStarter System

T TC

3

The heart of Voith’s hydrodynamic

torque converter is its hydraulic cir-

cuit; consisting of a pump, turbine,

and a guide wheel with adjustable

guide vanes (see picture above

right). This is combined in a com-

mon 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 mech-

anical energy and transmitted to the

gas turbine / generator shaft. The

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

comple tely open (large mass flow),

the power transmission is at its

max imum. Commonly, a constant

speed driver such as an induction

motor or a diesel engine drives the

pump wheel (input shaft of the

torque converter).

Torque converter benefits, function and design

Basic design hydrodynamic torque converterThe benefits

n Voith torque converters are designed and built to meet customer

requirements. No other torque converter manufacturer offers this

service.

n Torsional vibration dampening and shock free power transmission;

consequently, no stress applied to connected equipment thus de-

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.

Because of the change in mass flow

(due to the adjustable guide vanes)

the turbine wheels’ speed is vari-

able 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 de-

creases.

Guide vanes(adjustable)

Pump wheel

Turbine wheel

4

n T = n Tmax

nT = nopt

nT = 0

Typical gas turbine start-up curveTypical high speed settingTypical low speed setting

1

4

3

Using a multi-position guide vane actuator, multiple hold points and acceleration speeds can easily be part of the control logic.

0 %Speed

Torq

ue

25

6

1 Breakaway2 Unfired

resistance3 Purge point

(air exchange)4 Firing speed5 Acceleration

resistance to self sustained speed

6 Self-sustained speed

Typical gas turbine start-up curve

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.

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.

TT TP h

TT

TP

h

nT = 0 nT = nTmax

1

2

3

TT : Turbine torqueTP : Pump torqueh : Efficiency1 : Turbine wheel2 : Pump wheel3 : Mass flow (oil)

4 5

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

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

Other Functions

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 tur-

bine for rapid maintenance avail-

ability

n Extended gas turbine water-wash

cycles

Typical starter system P&I diagram

1 Torque converter 2 Torque converter housing 3 Fill and drain valve 4 Control valve

(Filling and draining) 5 Guide vane adjustment 6 Orifice plate 7 Working oil supply 8 Lube oil and cooling oil supply 9 Working oil return10 Lube oil and cooling oil return11 Lube oil tank of gas turbine

8 10

M

M

M

T

R

109

4

3

56

1

2

11

7

6

Torque converter power chart

Power chart

Power versus input speed chart of exiting torque converters

●Torque converter for gas turbine starting

▲Torque converter in pump storage power plants

Conv

erte

r inp

ut p

ower

PP

in M

W

Converter input speed nP in rpm

400 600 1 000 2 000 4 000 6 000 8 0000.4

1

2

4

10

20

40

100

200

400

600

7

The model EL..Y with its single

stage turbine offers a torque multi-

plication factor of 4. Its balance of

features and torque characteristics

in combination with an integral tur-

ning gear makes it the ideal starter

for a broad range of gas turbines.

With the powerful hydrau lic 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 feed back system, the

torque converter becomes a true

variable speed drive with peak pre-

cision. 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 sys-

tem as available from VoithTurbo.

Examples of other options for turn-

ing the gas turbine are: In stall ing a

“pony” motor at the ODE of the

start ing motor or installing a sep-

arate turning gear.

Torque converter Model EL..Y the classic design

Selection of EL..YStarter 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

Lx = 100 %Lx = 75 %Lx = 50 %Lx = 25 %Lx = 0 %

Torque / speed characteristics

Lx : Guide vanes openTP : Input torqueTT : Output torquenP : Input speednT : Output speed

4.01.0

nP = constant

0.5

03.0

2.0

1.0

3.5

2.5

1.5

0.5

0 0.2nT / nP

T T / T

P

MP

0.6 1.00

7 8

Dimensions in mm

Simplified longitudinal section of torque converter

Type EL 10 YFG 6.5

1 Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Filling and draining valve 8 Working oil supply 9 Working oil return10 Lube oil return11 Axial bearing12 Radial bearing13 Hydraulic cylinder14 Guide vane actuator

1 6 5 3

87 9

10

10

2 12 11 4 6 13 14

Type EL 10,5 YG 10

357 540 1260

2150

880

Ø11

9

Ø18

0

650

1880

Type EL 7,5 YFG 2.2

600 720174

1164

Ø80

Ø11

0

475

852

Type EL 10 YFG 6.5

900

1651

323 360 690

Ø10

0

Ø16

0

650

1100

9

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

equipp ed, 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 pack ag-

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 con verter 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.

Lx = 100 %Lx = 75 %Lx = 50 %Lx = 25 %Lx = 0 %

Torque / speed characteristics

Lx : Guide vanes openTP : Input torqueTT : Output torquenP : Input speednT : Output speed

1.0

nP = constant

0.5

0

nT / nP

T T / T

P

T P

1

4

7

2

5

8

3

6

10

9

0 0.2 0.4 0.6 0.80

Selection of EL..Z

Starter Model EL 10 ZFG

Max. Input power (kW) 1 800

Input speed (rpm) 3 000

10

Dimensions in mm

Simplified longitudinal section of torque converter

Type EL 10 ZFG

1 Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Filling and draining valve 8 Working oil supply 9 Working oil return10 Lube and cooling oil

return

1 6 5 3

87 9

10

2 4 6

Type EL 10 ZFG

720 864

1092

111.8

Ø82

Ø12

7

555

1485

Selection of EL..

Starter Model EL 9 G 6.0EL 9 GTM

6.0-50EL 10 GTM

7.5-86

Max. Input power (kW) 6 000 3 400 6 000 7 500

Input speed (rpm) 3 600 3 000 3 600 3 600

Turning speed (rpm) – – 3.0 2.2

Breakaway torque (Nm) – – 50 000 86 000

11

Torque converter Model EL.. where power meets speed

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 actu ator, the

various operating points of the gas

turbine are easily obtained. The ro-

bust, modular housing is designed

for various torque con verter sizes

as well as other torque converter

types.

The hydraulic fluid for the torque

con verter 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.

Lx : Guide vanes openTP : Input torqueTT : Output torque

nP : Input speednT : Output speed

Lx = 100 %Lx = 75 %Lx = 50 %Lx = 25 %Lx = 0 %

Torque / speed characteristics

TT

TPT T

/ TP

T P

1.00

0.500.75

0.25

0.25

1.00

0.50

1.25

1.75

0.75

1.50

2.00

0

0

nT / nP

0 0.2 0.4 1.00.6 1.20.8 1.4

Selection of EL..

Starter Model EL 9 G 6.0EL 9 GTM

6.0-50EL 10 GTM

7.5-86

Max. Input power (kW) 6 000 3 400 6 000 7 500

Input speed (rpm) 3 600 3 000 3 600 3 600

Turning speed (rpm) – – 3.0 2.2

Breakaway torque (Nm) – – 50 000 86 000

12

1 6 5 3

12

11

2 4 7 8 7 6 910

1006 1260337

1700

Ø10

0

Ø11

9

650

1895

880 540

1195

1260357

1700

Ø11

9

Ø18

0

650

1945

Dimensions in mm

Type EL 9 G 6.0 Type EL 10 GTM 7.5-86

Simplified longitudinal section of torque converter

Type EL 9 G 6.0

1 Input shaft 2 Pump wheel 3 Turbine wheel 4 Output shaft 5 Adjustable guide vanes 6 Adjusting mechanism 7 Hydraulic cylinder for guide vane adjusting 8 Guide vane actuator 9 Housing10 Fill and drain valve11 Operating oil supply12 Operating oil return

13

Torque converter Model EL..YGTM with integral continuous turning gear

Like many of Voiths’ torque conver-

ters, 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-

sem bly and alignment work. The

turn ing gear is designed for long-life

with emphasis on high break-away

torque and long periods of low-

speed 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)

per mitting a high degree of customiz-

ation. A large number of this model

torque converter are in oper ation

world wide with integrated turn ing

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

add ition, an electro-pneumatic turn-

ing device is available for con nection

to the turning gear drive motor ac-

ces sory shaft for ultra-slow indexing

of the gas turbine. The same turning

gears are also avail able as stand

alone units.

Simplified longitudinal section of torque converter with integral turning gear

Type EL 9 YGTM 4.0-86

1 Input shaft 2 Output shaft 3 Pump wheel 4 Turbine wheel 5 Adjustable guide vanes 6 Housing 7 Filling and draining valve 8 Control valve for filling and

draining 9 Working oil supply10 Working oil return11 Overrunning clutch12 Worm gear13 Electric motor14 Bevel gear

1 65 4 2 2 13

8 7 10 39 12 11 12 11 14

Selection of EL..YGTM

Starter Model EL 9 YGTM 4.0-86 EL 10,5 YGTM 10-110

Max. Input power (kW) 4 000 10 000

Input speed (rpm) 3 600 3 600

Turning speed (rpm) 2.4 6.0

Breakaway torque (Nm)

86 000 110 000

14

Dimensions in mm

680261.4 597.6 830

1150

1891Ø

100 12

22

Ø18

0

540

Type EL 9 YGTM 4.0-86

15

Torque converter EL..ZGTM with integral hydraulic turning device

This Voith torque converter with inte-

grated 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.

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 var-

ious limit and position switches.

Simplified longitudinal section of torque converter with integral turning device

Type EL 7,5 ZGTM

1 Input shaft 2 Output shaft 3 Pump wheel 4 Turbine wheel 5 Adjustable guide vanes 6 Housing 7 Filling and draining valve 8 Control valve for filling and

draining 9 Working oil supply10 Working oil return11 Overrunning clutch12 Return stroke

piston / cylinder13 Working stroke

piston / cylinder

1 6 11 13 114 35 2

8

9 10

7 12 13

Selection of EL..ZGTM

Starter Model EL 7,5 ZGTM EL 10 ZGTM-46

Max. Input power (kW) 1 000 1 800

Input speed (rpm) 3 600 3 000

Turning speed (rpm) 45° intermittent 45° intermittent

Breakaway Torque (Nm) 35 000 46 000

16

Dimensions in mm

Type EL 7,5 ZGTM

600 720108 251.5

1340

475

1009

Ø11

9

Ø80

Selection of E..

Starter Model E 5 WAT E 6 WAT E 6 YAT E 7 WAT E 7 W E 7 Y E 8 W

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°

intermittent45°

intermittent45°

intermittent45°

intermittent– – –

Breakaway torque (Nm)

11 000 11 000 11 000 11 000 – – –

17

Torque converter Type E.. with fixed guide vanes the compact one

TP : Input torqueTT : Output torque

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

avail ability, 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

com pact 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.

TP

TT

T 0

1

2

3

4

5

nT / nPnP = constant

0 0.2 0.4 0.6 0.8 1.0 1.2

18

Dimensions in mm

Simplified longitu- dinal section of torque converter

Type E 7 WAT

1 Input shaft with connecting coupling

2 Pump wheel3 Turbine wheel4 Fixed guide vanes5 Gear stage6 Output shaft7 Hydrostatic turning

device8 Working oil supply9 Working oil return

P&I diagram of Type E 7 WAT1 24

98

3 5 6 7

1 Torque converter2 Oil pump3 Relief valve4 Helical gear

stage5 Hydrostatic

turning device6 Overrunning

clutch

T

4

3

5

6

1R

nP

na

nT

2

Type E 7 W without turning device

50.8

870

Ø35

2.48

Ø78

.3

Ø62

0

Ø44

7.7

Type E 6 WAT

720111.8

Ø82 Ø12

7

Ø44

7.7

Ø35

2.48

1092

74

Gas Turbine Starters

GT Starter Model

EL 6,8 YFG EL 6,8 YFG EL 7,5 ZGTM EL 7,5 YGTM 2.2-86

EL 7,5 YGTM 2.2-36

EL 7,5 YGTM 2.2-46

EL 10 YGTM 6.5-110

EL 9 G 6.0 EL 9 G 6.0 EL 9 GTM 6.0-50

EL 10 GTM 7.5-86

EL 10,5 YGTM 10-110

Cranking (HP) 1 076 1 005 1 200 2 500 2 146 2 500 5 000 3 755 4 025 4 025 10 060 12 874

Power (kW) 800 750 896 1 865 1 600 1 895 3 700 2 800 3 000 3 000 7 500 9 600

Speed (rpm) 3 600 3 000 3 600 3 600 3 600 3 600 3 000 3 000 3 600 3 600 3 600 3 600

Turning speed (rpm)

– –45°

intermittent2.4 2.3 2.3 3.0 – – 3.0 2.2 6.0

Breakaway Torque

– –

– –

35 000 Nm 25 800 ft-lbs

86 000 Nm 63 400 ft-lbs

36 000 Nm 26 500 ft-lbs

46 000 Nm 33 900 ft-lbs

110 000 Nm 81 100 ft-lbs

– –

– –

50 000 Nm 36 800 ft-lbs

86 000 Nm 63 400 ft-lbs

110 000 Nm 81 100 ft-lbs

19

Packaged Starter a complete-system solution

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.

Schematic diagram for oil circuit of El 9 G 6.0 Package

1 Torque converter 2 Torque converter housing 3 Starting motor 4 Control valve for guide vane

position 5 Guide vane actuator 6 Transducer 7 Filter for control oil 8 Filling and draining valve 9 Thermocouples10 Cooling oil11 Indicator for guide vane

position12 Working oil pump13 Pressure gauge lube oil

pressure

Gas Turbine Starters

GT Starter Model

EL 6,8 YFG EL 6,8 YFG EL 7,5 ZGTM EL 7,5 YGTM 2.2-86

EL 7,5 YGTM 2.2-36

EL 7,5 YGTM 2.2-46

EL 10 YGTM 6.5-110

EL 9 G 6.0 EL 9 G 6.0 EL 9 GTM 6.0-50

EL 10 GTM 7.5-86

EL 10,5 YGTM 10-110

Cranking (HP) 1 076 1 005 1 200 2 500 2 146 2 500 5 000 3 755 4 025 4 025 10 060 12 874

Power (kW) 800 750 896 1 865 1 600 1 895 3 700 2 800 3 000 3 000 7 500 9 600

Speed (rpm) 3 600 3 000 3 600 3 600 3 600 3 600 3 000 3 000 3 600 3 600 3 600 3 600

Turning speed (rpm)

– –45°

intermittent2.4 2.3 2.3 3.0 – – 3.0 2.2 6.0

Breakaway Torque

– –

– –

35 000 Nm 25 800 ft-lbs

86 000 Nm 63 400 ft-lbs

36 000 Nm 26 500 ft-lbs

46 000 Nm 33 900 ft-lbs

110 000 Nm 81 100 ft-lbs

– –

– –

50 000 Nm 36 800 ft-lbs

86 000 Nm 63 400 ft-lbs

110 000 Nm 81 100 ft-lbs

20

12

Dimensions in mm

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,

pack aged 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 select ed to com-

pli ment each other, achiev ing an eco-

nomical and space consc ious design.

Due to the torque con verter charac-

ter istic, 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.

Type EL 9 G 6.0

11

2

3

13

4

5

67

8

10

1 9

2986 18

76

1651

2530

3505

6180

366

1700

cr22

8en,

S&

F-a

ik / S

VG

, 1.2

011,

2 0

00. D

imen

sion

s an

d ill

ustr

atio

ns w

ithou

t obl

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ion.

Sub

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ns.

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

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