design of a specific matlab code for processing of standar tensile test data for sheet metal forming simulation
Transformer Design
foundation of transformer
Q=input('enter the value of kVA rating');%in our case-125kVA; f=input('enter nominal frequency');%may be use to design pulse transformer V1=11;%primary voltage in kV k=0.45; %for 3 phase core type distribution transformer Et=k*sqrt(Q); phim=Et/(4.44*f); Bm=input('enter the value of magnetic flux density'); Ai=1e6*phim/Bm;%net iron area in mm2 d=sqrt(Ai/0.6); %diametr of circumscribing circle{Ai=0.6*d^2(for 3 stepped)} a=0.9*d;%width of largest stamping kw=10/(30+V1);%window space factor for rating 50-200 kVA cd=input('enter the value of current density (A/mm2)'); Aw=Q*1e6/(3.33*f*Bm*kw*cd*1e6*Ai*1e-6*0.001); %Q=3.33*f*Bm*kw*cd*Aw*Ai*0.001 Aw=window area in mm2 k1=input('enter the ratio of window height to window width i.e. Hw/Ww');%vary from 2-4 Ww=round((Aw/k1)^0.5); %Aw=Hw*Ww=ki*Ww^2 width of window in mm Hw=round(k1*Ww)%height of window in mm Dis=Ww+d%distance b/w adjacent limbs Ay=1.2*Ai%area of yoke{taken larger than limb so that flux is reduced in yoke} Agy=Ay/0.9%stacking factor=0.9 Dy=a%taking yoke as rectangular Hy=Agy/Dy%height of yoke H=Hw+2*Hy %overall height W=2*Dis+a%overall width V2=400 %secondary line voltage V2ph=V2/sqrt(3) %secondary per phase voltage Ts=V2ph/Et %turns per phase I2=Q*1000/(3*V2ph) %secondary phase current a2=I2/cd %area of secondary conductor in mm2 %standard area=79.1mm2 size of wire are 20*4mm and 25*3.2mm and the thickness of %insulation is taken as 1mm. %If we take Hw/Ww=3, then % If we use 20*4mm strip it doesn't effectively fit in the window using two % layer helical winding, that's why we use 25*3.2mm strip and three layer % winding %If we take Hw/Ww=4, then % we get clearance on each side = 2mm, but the minimum clearance % required is 6mm, that's why we are not using the Hw/Ww=4 with 2-layer winding cdn=I2/79.1 % new current density acc. to standard size. Ns=V2/(1.731*Et) %no. of turns per phase on secondary winding Nsl=round((Ns/3)+1) %no. of turns per phase per layer in secondary winding thcs=Nsl*25.1 %total height of conductor in one layer of secondary clrs=(Hw-thcs)/2 %clearance on each side of the layer %clearance is within standard limits %pressboard of 0.5mm is used between three layers and of 1.5mm between core %and first layer thus total width of the winding is IDs=d+(2*1.5)
rds=(3*3.3)+(2*0.5)% radial depth ODs=2*((3*3.3)+(2*0.5)+1.5)+d % outer diameter of secondary winding in window %design of high voltage winding Tp=V1*1000/Et % primary turns per phase Tp5=1.05*Tp; %for +-5% tappings % We are employing total of 8 coils of primary winding and each coil has 24 layers Tpc=round(Tp5/8) %turns per coil Tpl=Tpc/24 % turns per layer maximum_voltage_btw_layers=2*Tpl*Et %maximum_voltage_btw_layers is below the allowable limit I1=Q*1000/(3000*V1) %primary current per phase cdp=2.5 % current density on primary side is larger due to better cooling a1=I1/cdp % Dc=sqrt(4*a1/3.14) % diameter of bare conductor %we are using paper covered conductors for high voltage winding % so for given diameter the standard value of diameter of 1.4mm with fine % covering is 1.575mm a1n=3.14*(1.4^2)/4 % modified area cdpn=I1/a1n % new current density % 10mm space is employed betweeen adjacent coils so thcp=Tpl*8*1.575+8*10 %total height of conductor in one layer of primary clrp=(Hw-thcp)/2 % clearance. This is used by insulation and bracing % Radial insulation is done with paper of 0.3 mm thick thl= 10 % thickness_of_insulation_between_HV_and_LV_winding in mm IDp=round(ODs+2*thl) rdp=24*1.575+23*0.3 % radial depth of coil ODp=round(ODs+2*thl+2*(24*1.575+23*0.3)) % outer diameter of primary clearance_bw_adjacent_HVwindings=Dis-ODp % RESISTANCE MEASUREMENT mdp=(ODp+IDp)/2 % mean diameter lmtp=3.14*mdp/1000 % length of mean turn of primary winding in meters Rp=Tp*0.021*lmtp/a1n %resistance at 75"C mds=(ODs+IDs)/2 lmts=3.14*mds/1000 Rs=Ts*.021*lmts/a2 R=Rp+Rs*(Tp/Ts)^2 % total R referred to primary Rpu=I1*R/(V1*1000) %LEAKAGE REACTANCE mdw=(ODp+IDs)/2 % mean diameter of winding lmtw=3.14*mdw/1000 %length of mean turn of winding hw=(thcs+thcp)/2 %height of winding
X=2*3.14*f*4*3.14*1e-7*(Tp^2)*(lmtw/hw)*(thl+(rdp+rds)/3)*1e-3 % referred to primary Xpu=I1*X/(V1*1000) Zpu=sqrt((Rpu^2)+(Xpu^2)) %REGULATION puRu=Rpu %per unit regulation at unity pf puRl=Rpu*0.8+Xpu*0.6 % per unit regulation at lagging pf %LOSSES ohmloss=3*(I1^2)*R %taking stray losses to be 15% of ohmic losses TOL=1.15*ohmloss % total ohmic loss %density of laminations=7.6*1e3 kg/m3 Wtl=3*Ai*Ww*1e-9*7.6*1e3 % weight of limbs % Bm in limbs=1.3Wb/m2 so specific core loss=2 W/kg corelossl=2*Wtl % core loss in limbs Wty=2*W*Ay*1e-9*7.6*1e3 % Bm in yoke=1.1Wb/m2 so specific core loss=1.2 W/kg corelossy=1.2*Wty TCL=corelossl+corelossy %total core loss
%EFFICIENCY TLfl=TOL+TCL % total loss at full load eff=(Q*1000)/(Q*1000+TLfl) % efficiency at unity pf and full load %for max efficiency max_eff_occurs_at_this_load=sqrt(TCL/TOL)*100
OUTPUT enter the value of kVA rating125 enter nominal frequency50 enter the value of magnetic flux density1.3 enter the value of current density (A/mm2)2.3 enter the ratio of window height to window width i.e. Hw/Ww3 Hw = 420
