Turning Gear for Gas Turbines - Voith Turbo

Turning Gear for Gas Turbines

Design
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
capability
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

Function
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
rotation.
An overload limitation can be used
to protect the internal parts of the
gear and the gas turbine or generator
related parts against excessive
torque.
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
worksheet
■ 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)
CW CCW
■ 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
vs.drives@voith.com
www.variable-speed.com
www.voithturbo.com
Cr 289 e KO/WA 07/2007 Print run 2000. Printed in Germany. Subject to modifications due to technical development.