(27) Size of Transformer's Circuit Braker & Fuse (10.6.13)
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Enter Data in White Background Cells Calculate Size of Transformer / Fuse / Circuit Calculation Size of Circuit Breaker & Fuse are as per NEC 450.3 CONNECTED EQUIPMENT TO TRANSFORMER Sr.No Equipment Kw P.F Qty Equipment D.F 3 1 1 100% Total Load (Kva Total Load D.F Total D.F (Kva)
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Transcript of (27) Size of Transformer's Circuit Braker & Fuse (10.6.13)
Enter Data in White Background Cells
Calculate Size of Transformer / Fuse / Circuit BreakerCalculation Size of Circuit Breaker & Fuse are as per NEC 450.3
CONNECTED EQUIPMENT TO TRANSFORMER
Sr.No Equipment Kw P.F Qty Equipment D.F Total Kva D.F (Kva)
3 1 1 100% 3 3
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
Total Load (Kva) 3
Total Load D.F 100%
Total D.F (Kva) 3
Transformer Details
Total D.F Load 3 Kva
Primary Side Voltage (L-L): 415 Volt
Secondary Side Voltage (L-L): 230 Volt
Transformer Impedance: 5%
Transformer Connection Y-Y
Size of Transformer: 3 Kva OR Kva 3Efficency of Transformer at Full Load 98.40% 0.984
Efficency of Transformer at 1/4 Load 97.50% 0.975
Location of Transformer
Provide Protection on Transformer: Pri.Side & Sec.Side
Type Protection on Primary & Secondary Side:
:Results:
Transformer Voltage / CurrentPrimary Line Voltage (L-L) 415 Volt
Primary Phase Voltage (L-P) 240 Volt
Primary Line Current(L-L): 4 Amp
Primary Phase Current(L-P): 4 Amp
Secondary Line Voltage (L-L) 230 Volt
Secondary Phase Voltage (L-P) 133 Volt
Secondary Phase Current(L-P): 7.5 Amp
Secondary Line Current(L-L): 7.5 Amp
Size of Circuit Breaker / Fuse (As per NEC 450.3)Size of Circuit Breaker on Primary Side: 10 Amp
Size of Fuse on Primary Side: 10 Amp
Size of Circuit Breaker on Secondary Side: 10 Amp
Size of Fuse on Secondary Side: 10 Amp
Transformer LossesTotal Losses@ Full Load 49 Watt
Total Losses@ 1/4 Load 19 Watt
Full Load Copper Loss 32 Watt
Core Loss 17 Watt
Jignesh.Parmar www.electricalnotes.wordpress.com, [email protected] Detail of TC/CB/Fuse
Supervised Not Supervised
Circuit Breaker Fuse
Size of Transformer / Fuse / Circuit Breaker
1 13 36 69 10
15 1525 2030 25
37.5 3045 3550 40
75 45112.5 50150 60225 70300 80500 90750 100
1000 1101500 1252000 1502500 1603750 1755000 2007500 225
10000 25012000 30015000 35020000 40025000 45030000 50037500 60050000 70060000 80075000 1000
100000 12001600200025003000400050006000
Standard Size of 3 Phase Transformer (KVA)
Standard Size of Fuse / C.B (Amp)
HOME
UnSupervised
Fuse / Inverse Time C.B as per NEC (Amp)
136
10152025303540
455060708090
100110125150160175200225250300350400450500600700800
100012001600200025003000400050006000
3UnSupervised Supervised 2
Fuse / Inverse Time C.B as per NEC (Amp) Fuse / Inverse Time C.B as per NEC (Amp) 3 Phase T.C (KVA)
1 1 1 16 3 3 3
10 6 6 615 10 10 920 15 15 1525 20 20 2530 25 25 3035 30 30 37.540 35 35 4545 40 40 50
50 45 45 7560 50 50 112.570 60 60 15080 70 70 22590 80 80 300
100 90 90 500110 100 100 750125 110 110 1000150 125 125 1500160 150 150 2000175 160 160 2500200 175 175 3750225 200 200 5000250 225 225 7500300 250 250 10000350 300 300 12000400 350 350 15000450 400 400 20000500 450 450 25000600 500 500 30000700 600 600 37500800 700 700 50000
1000 800 800 600001200 1000 1000 750001600 1200 1200 1000002000 1600 16002500 2000 20003000 2500 25004000 3000 30005000 4000 40006000 5000 50006000 6000 6000
233 6
3 Phase T.C (KVA) 1 Primary Secondary
1 3 C.B Fuse C.B 3 6 1 600% 300% 250%6 9 2 600% 300% 125%9 15 600% 300% 250%
15 25 25 13 1925 30 25 10 1530 37.5
37.5 4545 5050 75 More Than 600V
75 112.5
%Imp
Primary112.5 150 >600150 225 C.B Fuse225 300300 500 1% 600% 300%500 750 2% 600% 300%750 1000 3% 600% 300%
1000 1500 4% 600% 300%1500 2000 5% 600% 300%2000 2500 6% 600% 300%2500 3750 7% 400% 300%3750 5000 8% 400% 300%5000 7500 9% 400% 300%7500 10000 10% 400% 300%
10000 1200012000 1500015000 2000020000 25000 Prim. 5% 0 C.B25000 30000 Sec. 0 C.B30000 3750037500 5000050000 6000060000 7500075000 100000 Prim. 5% 0 C.B
100000 100000 Sec. 0 C.B
More Than 600V
%Imp
Primary>600
C.B Fuse
1% 600% 300%2% 600% 300%3% 600% 300%4% 600% 300%5% 600% 300%6% 600% 300%7% 400% 300%8% 400% 300%9% 400% 300%
10% 400% 300%
Maximum Rating of Over current Protection for Transformers Less than 600 Volts
Protection Primary Protection
Method 2A to 9A
125%(NH) 167%
250% 250%
Primary Only Primary only protectionAmp Pri Sec
1 300% 0%2 167% 0%3 167% 0%4 167% 0%5 167% 0%6 167% 0%7 167% 0%8 167% 0%9 167% 0%
10 125% 0%
4.17 167% 0%
More than 9A
Primary only protection
Primary and secondary protection
7.53 6.97 N/A6 N/A
Primary & Secondary protectionAmp Pri Sec
1 250% 167%2 250% 167%3 250% 167%4 250% 167%5 250% 167%6 250% 167%7 250% 167%8 250% 167%9 250% 125%
10 250% 125%
4.17 250% 167%7.53 10.43 12.58
10 10
10 10
Secondary 0
Fuse250%125%250% Primary Secondary
19 C.B Fuse C.B Fuse15 10 10 10 10
More Than 600V Supervised
secondary>600 <600
C.B Fuse C.B/Fuse
300% 250% 250%300% 250% 250%300% 250% 250%300% 250% 250%300% 250% 250%300% 250% 250%250% 225% 250%250% 225% 250%250% 225% 250%250% 225% 250%
600% Fuse 300%250% Fuse 250%
600% Fuse 300%125% Fuse 125%
More Than 600V Not Supervisedsecondary
>600 <600C.B Fuse C.B/Fuse
300% 250% 125%300% 250% 125%300% 250% 125%300% 250% 125%300% 250% 125%300% 250% 125%250% 225% 125%250% 225% 125%250% 225% 125%250% 225% 125%
Maximum Rating of Over current Protection for Transformers Less than 600 Volts
Primary Protection Secondary Protection
300% Not required Not required
250% 125%(NH) 167%
0
Less than 2A
More than 9A
Less than 9A
0
