Tham khảo tài liệu 'electric machinery fundamentals (solutions manual) part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | EA 2825 10. V Problems 5-11 to 5-21 refer to a two-pole Y-connected synchronous generator rated at 470 kVA 480 V 60 Hz and PF lagging. Its armature resistance RA is . The core losses of this generator at rated conditions are 7 kW and the friction and windage losses are 8 kW. The open-circuit and short-circuit characteristics are shown in Figure P5-2. open Circuit Characteristic 1200 Field current A a 127 b Note An electronic version of the saturated open circuit characteristic can be foun in file and an electronic version of the air-gap characteristi can be found in file . These files can be used wit MATLAB programs. Column 1 contains field current in amps and column contains open-circuit terminal voltage in volts. An electronic version of th short circuit characteristic can be found in file . Column contains field current in amps and column 2 contains short-circuit termina _current in 5-11. a What is the saturated synchronous reactance of this generator at the rated conditions b What is the unsaturated synchronous reactance of this generator c Plot the saturated synchronous reactance of this generator as a function of load. Solution a The rated armature current for this generator is I -47-0 kVA . T 505 iA. 3 3 480V A L The field current required to produce this much short-circuit current may be read from the SCC. It is A3. The open circuit voltage at A is 880 V4 so the open-circuit phase voltage E is 880 V3 508 V. The approximate saturated synchronous reactance X S is 3 If you have MATLAB available you can use the file p52_scc. dat and the interpl function to look up this value as shown below. Note that column 1 of p52_scc contains field current and column 2 contains short-circuit terminal current. load if interp1 p52_scc 2 p52_scc 1 565 if
