excitation2研發(fā)培訓(xùn),設(shè)計培訓(xùn)(編輯修改稿)
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【文章內(nèi)容簡介】 ea L e n g t h 2 5 % Vo lts 5 0 % Vo lts 7 5 % Vo lts 1 0 0 % Vo lts 1 2 5 % Vo lts 1 5 0 % Vo lts? B AT ? B AT ? B AT ? B AT ? B AT ? B ATA ir GapSt ato r C o r eSt ato r T eethP o leR o to r Yo k eT o tal Open Circuit Saturation Curve Ampere Turns of Armature Reaction Recall that armature reaction is the effect that the armature mmf has on distortion of the open circuit noload mmf produced by the field acting alone. Armature Reaction can be modeled by adding an impedance in phase with the armature leakage reactance. Additional ampereturns need to be generated by the field to overe the effects of armature reaction AmpereTurns of Armature Reaction WmKA mpsCRT STP CSPPPHCA AT???????? 245.????????2sin4)sin (??????MCα: Pole Embrace PH: Number of phases SPP: Slots per pole per phase TPC: Turns per coil of armature CRTS: Number of armature circuits Amps: Rated amps of machine KW: Winding factor of machine Open Circuit Saturation Curve Direct Axis Synchronous Impedance Armature current Ampereturns per pole PU Terminal Voltage Open circuit sat O Nominal F rated D B A IZa C AAT NoLoad ampere turns G Short Circuit Ratio ? The Short Circuit Ratio (SCR) is from the previous curve OCOFSCRsat ?Short Circuit Ratio is a important parameter in synchronous motor design. It may be considered the ratio of field strength to armature strength. OCOGSCRunsat ? SCR SCR Low: – Small air gap – Poor voltage regulation (generators) – Small amount of field copper, an inexpensive field winding – Low Pull Out Torque (Motors) SCR High Large air gap good voltage regulation (generators) large amount of field copper, expensive field winding Excitation at Any Load and PF ? Recall that the Air Gap Voltage is the terminal voltage plus the armature resistance drop and armature leakage reactance drop added as vectors. This voltage is used to calculate the flux density under load (epct) I V IR IXL Vgap ? Open Circuit Saturation Curve Armature current Ampereturns per pole PU Terminal Voltage Nominal rated ATPg ATPs ATPFS Air Gap Voltage Field Excitation Calculation ATPg ? Leading PF ATPg ATPs Unity PF SMDS Output Efficiency Losses of a synchronous Motor Consist of 6 categories: Armature I2R Field I2R Core FW Stray Exciter Armature Copper Losses Armature copper loss: I2rated(Res) .3746.EffPFVHPILLrated ??????When doing this calculation, an initial value of efficiency must be assumed, the equations for efficiency and Rated current are then solved iteratively to get the final results. Calculate armature resistance at operating temperature. Field Copper Loss ? Using methods described on previous slide, calculate the full load field current. The field copper loss is then I2R(ResF) Calculate ResF at operating temperature Core Loss ? Core Loss Stator Teeth 3106095.85140?????????????????????? fWKBBPtittt? ?????? tsstkt bhKC LNSWPt: Tooth loss at noload in KW Wt: Weight of stator teeth Core Loss Cont. ? Bt: Flux density in middle of tooth kilolines/inches2 ? β: Exponent dependant on grade of steel, for standard 10502FH steel ? Ki: for circular stator laminations ? Ki: for Multi Segment Laminations, bracket type construction. ? Ki: for Multi Segment Lamination up to and including 20 poles ? Ki: for Multi Segment Laminations above 22 poles ? S1: Number of stator slots ? CLN: Net core length stator ? Kstk: Stacking factor for stator laminations ? hs: Stator slot height ? bt: Average tooth width
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鄂ICP備17016276號-1