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Unformatted text preview: What if the speed is 1880 RPM? 3. A 460V, fourpole, 50hp, 60Hz, Yconnected threephase induction motor develops its fullload torque at 3.8% slip when operating at 60Hz and 460V. The perphase circuit model impedances of the motor are: R s =0.33 , X s =0.42 , X r =0.42 , and X m =30 . Ignore mechanical, core, and stray losses. a. Find the rotor resistance R r . b. Find the maximum torque in addition to the slip and rotor speed at that torque. c. Find the starting torque (slip=100%). 4. A linear induction machine can be potentially used to launch aircraft on short runways. A similar machine is tested at no load by applying 4.6 kV, 400Hz and found to move at 50.0 m/s (180 km/h, ~112 mph). What is the stator spatial wavelength (the physical spacing between two different +A phase windings) for this machine? What voltage and frequency would you suggest to achieve 20 m/s?...
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This note was uploaded on 08/25/2011 for the course ECE 431 taught by Professor Bazzi during the Spring '11 term at University of Illinois at Urbana–Champaign.
 Spring '11
 Bazzi

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