Size a diesel generator for following electrical load. Future load expansion is 20%. Average use of equipment is 0.8.
1) 5 No. of 1 Ph, 230 V, 100 W, CFL bulb, diversity factor is 0.8, starting and running pf is 0.9.
2) 3 No. of 1 Ph, 230 V, 2500 W, Air conditioner with diversity factor of 1, starting and running PF is 0.9.
3) 4 No. of 1 Ph, 230 V, 600 W, halogen lights. Diversity factor is 0.8, starting and running PF is 0.9
4) 2 No. of 3 Ph, 430 V, 15 KW motor with Y-D starter having diversity factor of 0.8, starting P.F is 0.8 and running P.F is 0.9.
5) 2 No. of 3 Ph, 430 V, 100 KW, motor with soft starter having diversity factor of 0.8, starting P.F is 0.8 and running P.F is 0.9
Starting
Current of linear and non-linear loads
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||
Type Of
Load
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Equipment
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Starting
Current
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Linear
Load
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General
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100% of
full load current
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Non-linear
load
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UPS,
Inverter, Computer, Ballast
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160% of
full load current
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Starting
Current of different starters
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|
Type Of
Starter
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Starting
Current
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DOL
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6×Full load Current
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Star-Delta
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4×Full load Current
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Auto
Transformer
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3×Full load Current
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Soft
starter
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2×Full load Current
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VFD
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1.5×Full load Current
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Load Calculation 1:
F.L KW of CFL bulb = (No*Watt*D.F)/1000
=(5*100*0.8)/1000
=0.4 KW
F.L KVA of CFL bulb= KW/P.F
=0.4/0.9
=0.45 KVA
F.L KVA of CFL bulb= (No*Watt*D.F)/(Volt*P.F)
=(5*100*0.8)/(230*0.9)
=1.93 A
Type of load = Linear
Starting KVA of CFL bulb = 1 *(KW/starting P.F)
= 1*(0.4/0.9)
=0.45 KVA
Starting current of CFL bulb = 100% of F.L current
=1*1.93
= 1.93 A
Load Calculation 2:
F.L KW of A.C = (No*Watt*D.F)/1000
=(3*2500*1)/1000
=7.5 KW
F.L KVA of A.C = KW/P.F
=7.5/0.9
=8.33 KVA
F.L Current of A.C = (No*Watt*D.F)/(Volt*P.F)
= (3*2500*1)/(230*0.9)
=36.23 A
Type of load = Non-linear
Starting KVA of A.C = 1.6*(KW/starting P.F)
=1.6*(7.5/0.9)
=13.33 KVA
Starting current of A.C = 160% of F.L current
=1.6* 36.23
= 57.97 A
Load Calculation 3:
F.L KW of halogen bulb = (No*Watt*D.F)/1000
= (4*600*0.8)/1000
= 1.92 KW
F.L KVA of halogen bulb = KW/P.F
= 1.92/0.9
= 2.13 KVA
F.L current of halogen bulb = (No*Watt*D.F)/ (Volt*P.F)
= (4*600*0.8)/(230*0.9)
= 9.27 A
Type of load = Non-linear
Starting KVA of halogen bulb = 1.6*(KW/Starting P.F)
= 1.6*(1.92/0.9)
=3.41 KVA
Starting current of halogen bulb = 160% of F.L current
= 1.6*9.27
= 14.83 A
Load Calculation 4:
F.L KW of motor = (No*Watt*D.F)/1000
= (2*15000*0.8)/1000
= 24 KW
F.L KVA of motor = KW/P.F
=24/0.9
= 26.67 KVA
F.L current motor = (No*Watt*D.F)/ (Volt*P.F)
= (2*15000*0.8)/(1.73*430*0.9)
= 35.8 A
Type of starter = Star-Delta
Starting KVA of motor = 4*(KW/Starting P.F)
= 4*(24/0.8)
= 120
Starting current of motor = 4* F.L current
= 4*35.8
= 143.2 A
Load Calculation 5:
= 4*(24/0.8)
= 120
Starting current of motor = 4* F.L current
= 4*35.8
= 143.2 A
Load Calculation 5:
F.L KW of motor = (No*Watt*D.F)/1000
= (2*100000*0.8)/1000
= 160 KW
F.L KVA of motor = KW/P.F
=160/0.9
= 177.78 KVA
F.L current of motor = (No*Watt*D.F)/ (Volt*P.F)
= (2*100000*0.8)/(1.73*430*0.9)
= 238.98 A
Type of starter = Soft starter
Starting KVA of motor = 2*(KW/Starting P.F)
= 2*(160/0.8)
= 400 KVA
Starting current of motor = 2* F.L current
= 2*238.98
= 477.96 A
Total Load Calculation:
Total Starting KVA = 0.45+13.33+3.41+120+400
= 537.19 KVA
Total Starting Current = 1.93+57.97+14.83+143.2+477.96
= 695.89 A
Total Running KVA = 0.45+8.33+2.13+26.67+177.78
= 215.36 KVA
Total Running current = 1.93+36.23+9.27+35.8+238.98
= 322.21 A
Size of diesel Generator =(starting KVA*Future Expansion*Average use of equipment)
= (537.19*1.2*0.8)
Size of diesel Generator = 515.7 KVA.
= 2*(160/0.8)
= 400 KVA
Starting current of motor = 2* F.L current
= 2*238.98
= 477.96 A
Total Load Calculation:
Total Starting KVA = 0.45+13.33+3.41+120+400
= 537.19 KVA
Total Starting Current = 1.93+57.97+14.83+143.2+477.96
= 695.89 A
Total Running KVA = 0.45+8.33+2.13+26.67+177.78
= 215.36 KVA
Total Running current = 1.93+36.23+9.27+35.8+238.98
= 322.21 A
Size of diesel Generator =(starting KVA*Future Expansion*Average use of equipment)
= (537.19*1.2*0.8)
Size of diesel Generator = 515.7 KVA.
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