LECTURE 24 INDUCTION MACHINES (1)

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1 ECE 330 POWER CIRCUITS AND ELECTROMECHANICS LECTURE 24 INDUCTION MACHINES (1) Acknowledgment-Thee handout and lectue note given in cla ae baed on mateial fom Pof. Pete Saue ECE 330 lectue note. Some lide ae taken fom Ali Bazi peentation Diclaime- Thee handout only povide highlight and hould not be ued to eplace the coue textbook. 12/4/2017

2 INDUCTION MACHINES Mot widely ued machine in the induty Both the tato and the oto cay altenating cuent Ued in pump, compeo, fan, etc. Moto inductance can be contolled to have excellent toque-peed capabilitie. Analyi baed on equivalent cicuit deived fom the enegy point of view 12/4/2017 2

3 INDUCTION MACHINES, 12/4/2017 3

4 PHYSICAL FEATURES AND FREQUENCY RELATIONSHIPS It ha a thee-phae winding on both the tato and the oto, wound fo P pole The thee-phae winding on the oto i hot cicuited eithe though extenal mean o on the oto itelf Wound oto Squiel cage oto Two baic component: the tato and the oto Analogou to a tanfome with otating econday. 12/4/2017 4

5 WOUND ROTOR The oto winding that otate with the oto ae connected to lip ing. The fixed buhe povide a hot-cicuited path though an extenal eitance 12/4/2017 5

6 WOUND ROTOR Extenal eitance i ineted to achieve a deied toquepeed chaacteitic. A highe tating toque can be achieved togethe with limited contol ove peed. Souce: pinteet.com 12/4/2017 6

7 SQUIRREL CAGE ROTOR Roto winding hoted on the oto itelf A fixed-toque peed chaacteitic The conducto though the lot ae imply hoted though a ing at the end 12/4/2017 7

8 OPERATION OF AN INDUCTION MACHINE Thee-phae cuent ae upplied to the tato winding, eulting in a otating field. Each phae may be wound fo field evolve at the ynchonou peed pole o that the otating given by whee i the fequency in Hz and i in evolution f pe minute (pm) p N N f pn = /4/2017 8

9 OPERATION OF AN INDUCTION MACHINE Cuent ae induced in the oto winding, which inteact with the otating field to poduce toque. The peed inceae to a point whee the toque developed between oto and tato i jut enough to balance the oppoing mechanical load toque So long a the oppoing toque (due to beaing fiction,.. etc., unde no-load condition) exit, the oto peed can neve equal the peed of the tato otating field peed. 12/4/2017 9

10 OPERATION OF AN INDUCTION MACHINE The oto cuent have a fequency. Mechanical peed in mechanical ad pe econd atifie the elation by p = m 2 The fequency of induced cuent in the oto i We define a new dimenionle quantity called lip a 12/4/ p = m electical ad / ec 2 N N a = ct N

11 OPERATION OF AN INDUCTION MACHINE N : The ynchonou peed in pm, N act : the actual peed of the oto 2 p 120 pn 2 p 2 N act = 2 pn 120 p 2 N act p 2 f = = 2f Multiplying the ight ide by we get 12/4/ m

12 OPERATION OF AN INDUCTION MACHINE So, m = / m 1 p mechanical ad ec p Since p = m electical ad / 2 ec So, 12/4/

13 OPERATION OF AN INDUCTION MACHINE Fom thi Whee f f = f i the fequency of cuent in the oto Slip i dimenionle, and it give an idea of the peed of the machine with epect to the ynchonou peed. =0 =1 coepond to ynchonou peed coepond to tandtill o tating condition i a vey mall numbe between 0.01 to /4/

14 EXAMPLE 7.1 Conide a thee-phae, 60 Hz, ix-pole induction machine un at 1125 pm. Find the lip and the oto cuent fequency. f f pn = 120 N = = pm = = f = f = (0.0625)60 = 3.75 Hz 12/4/

15 ANALYSIS OF A TWO-POLE MACHINE Jut a in the cae of the ynchonou machine, we fit do the analyi fo a two-pole machine and then genealize to a P pole machine. The tato ha thee-phae winding. Unlike in the ynchonou machine, thee ae thee winding on the oto, Label fo tato winding Label fo oto winding 12/4/

16 DERAVATION OF AN EQUIVALENT CIRCUIT 12/4/

17 DERAVATION OF AN EQUIVALENT CIRCUIT i elation i i a a i b b i c c = A iˆ a a ˆ b i b c iˆ c 12/4/

18 DERAVATION OF AN EQUIVALENT CIRCUIT whee the matix A i Lm Lm L M co M co( 120 ) M co( 120 ) 2 2 Lm Lm L M co( 120 ) M co M co( 120 ) 2 2 Lm Lm L M co( 120 ) M co( 120 ) M co 2 2 Lm L m L 2 2 T Lm L m M L 2 2 Lm Lm L /4/

19 DERAVATION OF AN EQUIVALENT CIRCUIT L = L L m i the elf-inductance of the tato coil L = L L m The leakage inductance L, The magnetizing inductance Mutual inductance i the elf-inductance of the oto coil 2 N 0 =, N 0 L, m Lm = 2 g 2 g N N 0 M = N 4 g N L = L M L = N, L M N 12/4/ L 2

20 DERAVATION OF AN EQUIVALENT CIRCUIT Machine paamete: g i the ai gap length, i the adiu of the ai gap, i the axial length of the coe, N and N ae the effective tun pe phae on the tato and oto, epectively. Note that fo both the tato and oto winding, the cuent diection ae into the winding. The oto cuent ae iˆa iˆb denoted a,, and into the coil i ĉ 12/4/

21 DERAVATION OF AN EQUIVALENT CIRCUIT Fo two-phae machine a L 0 M co M ini a b 0 L M in M co i b co in 0 ˆ a M M L i a b M in M co 0 L iˆ b Let the angle between the oto and tato axe of phae a be = m t Electic toque equie = m Intead of, 0 m (ynchonou) 12/4/

Rotating Field Voltage Analysis on the Stator and Rotor of the Inverted Rotor Induction Motor

Rotating Field Voltage Analysis on the Stator and Rotor of the Inverted Rotor Induction Motor Poceeding of the 6th WSEAS Intenational Confeence on Application of Electical Engineeing, Itanbul, Tukey, May 7-9, 007 17 Rotating Field oltage Analyi on the Stato and Roto of the Inveted Roto Induction