Motors

Electric MotorsClassification / types DC Motors AC Motors Stepper Motors Linear motorsFunction Power conversion - electrical into mecanical Positional actuation electrical si!nal to positionDC Motors DC Motors Fun"amental caracteristics #asic function $ypes an" applications Series Sunt Com%ination $or&ue caracteristics Mo"elin!Fun"amental caracteristics of DC MotorsEn" view$ime 'En" view$ime '(Siftin! ma!netic fiel" in rotor causes rotor to %e force" to turn)ature of commutation Power is applie" to armature win"in!s From *( $rou! te (%rus $rou! te commutator contacts $rou! te armature +rotor, win"in! $rou! te %rus $o *- -otation of te armature moves te commutator. switcin! te armature win"in! connections Stator may %e permanent or electroma!netDC motor wirin! topolo!iesSeries /oun" DC motors Armature an" fiel" connecte" in a series circuit0 Apply for i! tor&ue loa"s tat "o not re&uire precise spee" re!ulation01seful for i! %rea2away tor&ue loa"s0 locomotives. oists. cranes. automo%ile starters Startin! tor&ue 3''4 to as i! as 5''4 of full loa" tor&ue0 Loa" increase results in %ot armature an" fiel" current increase $erefore tor&ue increases %y te s&uare of a current increase0 Spee" re!ulation Less precise tan in sunt motors6 Diminise" loa" re"uces current in %ot armature an" fiel" resultin! in a !reater increase in spee" tan in sunt motors0 )o loa" results in a very i! spee" wic may "estroy te motor06 Small series motors usually ave enou! internal friction to prevent i!-spee" %rea2"own. %ut lar!er motors re&uire e7ternal safety apparatus0Sunt woun" DC motors Fiel" coil in parallel +sunt, wit te armature0 Current trou! fiel" coil is in"epen"ant of te armature06 -esult 8 e7cellent spee" control0 Apply were startin! loa"s are low fans. %lowers. centrifu!al pumps. macine tools Startin! tor&ue 9:;4 to :''4 full loa" tor&ue +3'' for sort perio"s,0Compoun" woun" DC motors Performance is rou!ly %etween series-woun" an" sunt-woun" Mo"erately i! startin! tor&ue Mo"erate spee" control e0 #est applications for i! tor&ue at low spee" intermittent "uty0 Servos. power seats. win"ows. an" win"siel" wipers0Mo"elin! DC motors A linear spee"/tor&ue curve can %e use" to mo"el DC motors0$is wor2s well for PM an" compoun" "esi!ns an" can %e use" for control mo"els for narrow ran!es for te oter confi!urations Mo"el will assume? Linearity Constant termal caracteristics )o armature in"uctance )o friction in motorDC Motor mo"elin!] / [ A Nm Kt =bE IR V + =e bK E =I K Tt=Motor e&uationsFrom te circuitetK RKTV + =RK KTKVt e t = Su%stitutin! te a%ove@RV KTes =tnKV= For stalle" rotor tor&ueAn" no-loa" spee"TK KRt en =