Page 268 - Steam Turbines Design, Applications, and Rerating

Transmission Elements for High-Speed Turbomachinery 247

TABLE 13.1 Technical Data of a Back-Pressure Turboset
with and without Reduction Gear
Variant* Without reduction gear With reduction gear
Turbine speed, r/min 3000 9600
Generator speed, r/min 3000 1500
Control stage:
nominal diameter, mm 1020 450
Reaction stages:
number 58 19
Turbine casing:
mass, t 28.9 8.2
* Both variants are designed for the same efficiency at the generator coupling. Live steam =
80 bar/500°C; back pressure = 5 bar; Output = 14 MW.
SOURCE: Asea Brown-Boveri, Baden, Switzerland

Figure 13.9 shows a typical energy recovery application of a Maag syn-
chronous clutch coupling in a compressor installation where excessive
process gases are available. These gases, instead of being relieved by a
valve, are now used to drive a gas expander that is coupled via syn-
chronous clutch with a centrifugal compressor. In the case when no
excessive process gases are available, the gas expander will be dis-
connected automatically, thus avoiding windage losses in the gas
expander.
Many turbomachinery clutches are known as SSS clutches. The
manufacturer and licensor, SSS Gears Limited of Sunbury-On-
Thames, England, chose SSS to denote the “Synchro-Self-Shifting”
action of the clutch whereby the clutch teeth are phased and then auto-
matically shifted axially into engagement when rotating at precisely

TABLE 13.2 Technical Data of a 20-MW Extraction/Condensing Turboset
with and without Reduction Gear
Variant* Without reduction gear With reduction gear
Turbine speed, r/min 3000 7500
Generator speed, r/min 3000 1500
Control stages:
number 2 2
Type 2-row Single row
Nominal diameter, mm 1060 and 800 each 700
Reaction stages:
number 61 23
Turbine casing:
mass, t 56 35
* Both variants are designed for the same efficiency at the generator coupling. Live steam =
108 bar/520°C; extraction pressure = 10 bar; exhaust pressure = 0⋅1 bar.
SOURCE: Asea Brown-Boveri, Baden, Switzerland