Turning Gear for Gas Turbines - Voith Turbo


Turning Gear for Gas Turbines - Voith Turbo

Turning Gear for Gas Turbines


Within the last 25 years, Voith has

supplied more than 5 000 hydrodynamic

torque converters and more

than 1 000 of those with integrated

turning gears for starting and turning

gas turbines. These combined

units have starting powers from

400 kW up to 10 000 kW. The torque

range of the turning gears varies

from 6 000 to 110 000 Nm. However,

greater torque values can easily be

offered. With this experience we are

now taking the next logical step in

our product line with ”free standing”

turning gears.

The use of our well proven design

from the integrated version provides

the same outstanding reliability, availability

and service life our customers

are used to. Also our customers can

take advantage of our well established

and worldwide service network.

1. Inner ring of overrunning clutch

2. Outer ring of overrunning clutch

3. Cage with clamping pieces

4. Turning gear output shaft

5. Housing

6. Worm gear wheel

7. Worm gear shaft

8. Bevel gear (with overload

limitation if required)

9. Electric motor with manual turning


10. Antifriction bearings for worm

gear wheel

11. Antifriction bearings for worm

gear shaft

12. Radial sleeve bearing

13. Thrust bearing

14. Lube oil supply

15. Lube oil drain

16. Connection coupling


The inner ring (1) is connected to

the output shaft (4), and the outer

ring (2) to the worm gear (6). The

cage with the clamping pieces (3)

is connected to the inner ring (1).

The worm gear wheel (6) is driven

through the worm gear shaft (7)

and the bevel gear (8) is driven by

the electric motor (9).

The antifriction bearings (10, 11)

support the worm gear set in the

housing. The worm gear uses a

constant oil fi lling, independent of

the gas turbines oil supply.

The sleeve and thrust bearings

(12, 13) support the output shaft in

the housing. These bearings are

supplied with lube oil from the gas

turbine oil system.

The cage with the clamping pieces

(3) always rotates with the output

shaft (4). Even a low speed of the

output shaft (4) lifts the clamping

pieces (3) due to centrifugal force

of the outer ring (2). Consequently

the outer ring (2) is no longer connected

to the inner ring (1). During

gas turbine operation the overrunning

clutch operates without contact

and thus wear free.

If the gas turbine speed decreases

to a value below 200 rpm, the centrifugal

force decreases to such an

extent that the clamping pieces (3)

touch the outer ring (2) again due to

spring tension. If the inner ring (1)

now rotates slower than the outer

ring (2), the overrunning clutch is

engaged and a torque can be transmitted

from the outer ring (2) to the

inner ring (1).

The torque can only be transmitted

in one predetermined direction of


An overload limitation can be used

to protect the internal parts of the

gear and the gas turbine or generator

related parts against excessive


The following output shaft speeds

(gas turbine) can exist, when the

motor of the turning device is

switched on:

■ Output speed = 0:

The overrunning clutch is engaged;

the gas turbine breaks away

■ Output speed < outer ring speed:

The overrunning clutch is engaged;

the gas turbine is accelerated

to turning speed

■ Output speed > outer ring speed:

The overrunning clutch is disengaged;

no infl uence on the gas

turbine speed

Scope of supply

Turning gear

■ Attached base structure to „adapt“

to customers foundation

(upon request)

■ Connection coupling between

turning gear and generator

■ Electric motor

■ Manual turning device

■ Piping to locate lube oil feed &

drain connections in customer

specifi ed location (upon request)

■ Coupling guard

■ Factory assembling and testing

Data worksheet

Specifi c technical data


■ The unit is used for


gas turbine.

■ The design is according to

Turning Gear Specifi cation


Customer to defi ne:

Turning speed

__________________ rpm

■ Break away torque

__________________ ftlb or Nm

■ Continuous torque

__________________ ftlb or Nm

■ Direction of rotation

(looking in direction of power fl ow)


■ Voltage _____ DC or

_____ AC _____ Hz _____ Phase

■ Required design margin for break

away torque


Voith to defi ne:

■ Speed of electric motor

__________________ rpm

■ Power of electric motor

(continuous operation)

__________________ kW

■ Lube oil supply


■ Ratio of bevel gear


■ Ratio of worm gear


Voith Turbo GmbH & Co. KG

Variable-speed drives

Voithstraße 1

74564 Crailsheim

Tel. +49 7951 32-0

Fax +49 7951 32-650




Cr 289 e KO/WA 07/2007 Print run 2000. Printed in Germany. Subject to modifications due to technical development.

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