Air Compressor Driving with Synchronous Motors at Optimal Parameters

Transcription

1 Iuliu Petri, Adri Vleti Petri AALELE UIVERSITĂłII EFTIMIE MURGU REŞIłA AUL XVII, R., 010, ISS Air Compressor Drivig with Syhroous Motors t Optiml Prmeters I this pper method of optiml ompestio of the retive lod by the syhroous motors, drivig the ir ompressors, used i miig eterprises is preseted, tkig ito out tht i this se, the gret mjority of the equipmet (ompressors, pumps) re geerlly workig ostt lod. Keywords: ir ompressor, syhroous motor, retive lod 1. Itrodutio The ir ompressors with pisto re workig i the idustril eterprises, espeilly i the miig oes, due to the irese of the eed of ompressed ir. Beuse the istlled power of the ir ompressors is gret i the ompriso with the istlled power of the eterprises, the problem of optimizig the eletril drive presets gret eoomil importe. I the miig eterprises of our outry, the pisto ir ompressors re used lmost exlusively, drive by syhroous motors of powers, usully, i the rge of kw. These motors re fed from distributio sttios to whih re lso oeted other osumers, usully gret power syhroous motors, whih tke sigifit qutity of retive eergy. The ompestio of this retive lod be mde i dvtgeous oditios by usig the ir ompressor drivig syhroous motors, whih, t preset, work t uitry power ftor.. The method for determiig the optiml retive lod distributio mog the syhroous motors prtiiptig i the ompestio Geerlly, i ompressor sttio there re simulteously workig severl types of ompressors, drive by syhroous motors of differet prmeters. 53

2 The optiml ompestio o erti retive lod implies rtiol reprtitio of this lod mog the syhroous motors, prtiiptig i the ompestio. As optimizig riterio, tht reprtitio of the retive lod is estblished, whih gives miiml supplemetry tive eergy losses, P s, depedet o the produig of retive eergy. Beuse the produig of retive eergy by the syhroous motor implies it s over exittio, o estblishig the retive lod distributio, the limittios of the stbility i servie of the motor d its hetig must be tke ito out. The lultio method of the optiml distributio of retive power hs t its bse the speifi irese of the supplemetry tive power, whe produig the retive eergy []: dp = s (1) d For syhroous motors, the supplemetry losses, i the se of produig retive eergy, be lulted with the reltio: P s = Aq + Bq () Where: q= (3) Tkig ito out the reltio (), for the speifi irese of the tive power, the expressio obtied is: A B = + = + b (4) The speifi tive power irese depeds lierly o the produed retive power. The lultios effetuted for orete situtio show tht for lrge rge of motor lod vritios, the speifi iremet of the tive power mitis itself prtilly ostt, beig ot depedet o the lod of the motor. It be esily demostrted tht [], i the se of retive lod ompestio, with syhroous motors, hvig the speifi tive power iremets = + b, the miiml supplemetry tive power losses re obtied whe i i i the speifi iremets re the sme, i.e.: 1 = =... = i =... = (5) Cosequetly, tkig ito out the reltios (5) d: i = (6) The retive lod of eh motor results from the reltios: 54

3 b b b b b b = b1 b = 1 1+ b1 = b I the situtio whe the oetio of the motor to the br system is mde with ble of sigifit legth, the the losses i the ble must lso be tke ito out. These tive power losses re determied with the reltio: R P s= (8) U The speifi iremet of the tive power is obtied from the reltio: R = (9) U Where R is the resiste of the feedig ble. The totl speifi iremet of the tive power results from summrizig the reltios (4) d (9): A B R t = + + = + b (10) U Where: A R = + (11) U The reltio (7) givig the optiml distributio of the retive lod remi vlid i this se too, replig the i oeffiiets by i. The pplitio of this method i the se of ompressor drivig syhroous motors presets diffiulties i the prtie, beuse, i the mjority of the studied ses, diffiulties our t the determitio of the dt eessry for the lultio. I suh situtios the problem be solved i experimetl wy, by determiig for eh motor, the vritio of the sttor urret I, the exittio power P e d the retive power, with depedey o the exittio urret I e (figure 1). 3 (7) 55

4 Beuse the motors re workig t ostt lod, there is o problem i obtiig the hrteristis, these beig determied t this lod. For the motors tht hve exiter mouted o the shft, the exittio power is lulted with the reltio: UeIe P = (1) e Where η is the effiiey of the exiter. If the exiter is drive seprtely, the exittio power is mesured t the iput of the motor, drivig the exiter. η I P e I P e 0 I e Figure 1. The I, P e, = f(i e ) hrteristis of the syhroous motor The speifi power iremets for eh motor re: P + Pe + P P' P' e P' = (13) Where P re the losses i the sttor widigs, P = 3I R (14) P re the losses i the ble tht oets the motor to the feedig br 56

5 P = 3I R (15) Ad P, P e, P re the losses i the sttor, exittio d ble, if the motor works t osφ = 1. For eh motor the the = f() hrteristi is drw, represeted i figure. It is to otie, omprig reltio (10) to the = f() hrteristi, tht: EF = tg ψ =, b= OD (16) DF With the reltios (9) d (10), tht prt of the retive lod of eh motor, from the totl lod, whih is to be ompested, esily be determied, d from figure 1, results the orrespodig exittio urret. E ψ D F 0 G Figure. The = f() hrteristi of the syhroous motor 3. Colusios The ompestio of the retive lod i the sttios to whih ompressors drivig syhroous motors re oeted is etirely justified solutio, beuse of its fvorble eoomil effets. 57

6 The preseted experimetl method is simple, esy to pply d without supplemetry ivestmets, o oditio tht syhroous motors permit exittio overlod without exeedig dmissible het. Referees [1] Zăresu, H., Utilizre motorului siro î Ńioări eletrie, Ed. Tehiă, Buureşti, [] Syromitikov, I.A., Sihroije dvigteli, Goseergoizdt, Mosow Leigrd, Addresses: Prof. Dr. Eg. Iuliu Petri, Eftimie Murgu Uiversity of ReşiŃ, PiŃ Tri Vui, r. 1-4, 30085, ReşiŃ, i.petri@uem.ro Leturer Dr. Eg. Adri Petri, Eftimie Murgu Uiversity of ReşiŃ, PiŃ Tri Vui, r. 1-4, 30085, ReşiŃ,.petri@uem.ro 58