World Series — induction motors and generators, 250–30,000 hp, 460 V – 13.8 kV

Description

World Series® is a line of large squirrel-cage induction motors, the largest AC machines in the company's range. The series continues a tradition started in 1894 with the first industrial polyphase motors, Type B, and is intended for the most energy-intensive drives in heavy industry. The series also includes machines that operate in generator mode and two-speed PAM motors. The range covers horizontal and vertical motors from 250 to 30,000 hp at voltages from 460 V to 13,800 V, for 50 Hz and 60 Hz networks as well as for supply from variable frequency drives. The machines are built on the metric frame series per IEC, which allows an optimal design to be selected for any power, speed and voltage without gaps in the range and improves ventilation, reducing heating and ventilation losses. According to the manufacturer, computer design, improved insulation materials with a higher copper content and metric frames made it possible to reduce losses by up to 30 % compared with previous designs. Stator windings use the proprietary Thermalastic® insulation system: mica insulation of the coils in form-wound windings, vacuum pressure impregnation of the wound and connected stator with solvent-free epoxy resin, and oven curing; the cycle is repeated to eliminate voids that cause corona. The insulation withstands long-term voltage stress, moisture, contamination, thermal cycling and chemical effects. The bearing assembly uses split sleeve bearings with a spherical self-aligning seat, high-tin babbitt and a bronze oil ring; the lubrication can easily be converted to forced. Multistage sealing prevents oil leakage, optionally with buffer pressurization. Bearings are inspected through viewing windows, and covers are removed without disturbing the alignment of the unit. Rolling bearings (radial ball, angular contact and spherical roller) and hydrodynamic bearings are also available, insulated if required. The frame is a welded box construction with massive steel partitions and end plates, providing lateral and torsional stiffness and minimal vibration. The rotor is assembled from solid laminations clamped with bolts and pressure plates, with copper bars. At the design stage, the natural frequencies of the rotor-bearing system and the stresses are calculated by finite element analysis. Applications: pumps, fans, compressors, mills and crushers in power generation, oil and gas, chemical, mining, pulp and paper, and metallurgical industries. Large machines are manufactured and tested at the plant in Round Rock, Texas, USA, which has produced large DC motors since 1976, AC induction motors since 1977 and synchronous motors since 1978.

Technical specifications