Electrical Calculations

SCHEDULE OF LOADS AND COMPUTATION

CKT NAME KVA KW HP VOLTSLINE CURRENT

WIRE SIZEAB BC CA 3Ø

12345678

TOTAL 0 0 0 0

CKT NO.

CIRCUIT BREAKER

STANDARD 3 PHASE, 60HZ MOTOR DATA, 230VAC

HP KW Volts

1/4 0.2 1.1 2.0 14 15AT 3A 230VAC1/3 0.3 1.5 2.0 14 15AT 3A 230VAC1/2 0.4 2 2.0 14 15AT 6A 230VAC3/4 0.60 2.8 2.0 14 15AT 10A 230VAC1 0.75 3.6 2.0 14 15AT 10A 230VAC

1.5 1.1 5.2 2.0 14 15AT 15A 230VAC2 1.5 6.8 2.0 14 15AT 20A 230VAC3 2.5 9.6 2.0 14 20AT 25A 230VAC5 4 15.2 3.5 12 30AT 40A 230VAC

7.5 5.5 22 5.5 10 50AT 60A 230VAC10 7.5 28 8.0 8 50AT 70A 230VAC15 11 42 14 6 70AT 100A 230VAC20 15 54 14 6 100AT 150A 230VAC25 19 68 22 4 125AT 175A 230VAC30 22 80 30 2 125AT 200A 230VAC40 30 104 50 0 175AT 300A 230VAC50 37 130 60 00 200AT 350A 230VAC60 45 154 80 000 225AT 400A 230VAC75 55 192 125 250MCM 300AT 500A 230VAC100 75 249 200 400MCM 400AT 600A 230VAC

SIMPLIFIED MOTOR CIRCUIT CALCULATIONNOTES :

respectively

General Formula :

Full Load = HP ( 746 watts )K ( volts ) ( P.F. ) ( Eff. )

K = √3 for 3 phase , 1 for single phase P.F. = 0.80 to 0.85 Eff. = 0.80 to 0.90

CB Amp trip and fuse sizes are approximate selections for general installations

Full load current

WIRE SIZE in sq.mm

WIRE SIZE in AWG

CB, thermal - magnetic trip, amps

Safety switch, single

element

Motors 200 and 208 Volts increase, indicated full load current value by 15 and 10 %

Use FULL-VOLTAGE starters for motors up to 7.5 HP, reduced - voltage types for higherratings, that is, WYE - DELTA up to 150 HP and Auto - Transformer for bigger units

STANDARD 3 PHASE, 60HZ MOTOR DATA, 460VAC

HP KW Volts

1/4 0.2 0.6 2.0 14 15AT 3A 460VAC1/3 0.3 0.8 2.0 14 15AT 3A 460VAC1/2 0.4 1 2.0 14 15AT 3A 460VAC3/4 0.60 1.4 2.0 14 15AT 3A 460VAC1 0.75 1.8 2.0 14 15AT 6A 460VAC

1.5 1.1 2.6 2.0 14 15AT 10A 460VAC2 1.5 3.4 2.0 14 15AT 10A 460VAC3 2.5 4.8 2.0 14 15AT 15A 460VAC5 4 7.6 2.0 14 15AT 20A 460VAC

7.5 5.5 11 2.0 14 20AT 30A 460VAC10 7.5 14 3.5 12 30AT 35A 460VAC15 11 21 5.5 10 40AT 50A 460VAC20 15 27 8.0 8 50AT 70A 460VAC25 19 34 8.0 8 50AT 80A 460VAC30 22 40 14 6 70AT 100A 460VAC40 30 52 14 6 100AT 150A 460VAC50 37 65 22 4 125AT 175A 460VAC60 45 77 30 2 125AT 200A 460VAC75 55 96 38 1 150AT 250A 460VAC100 75 124 60 00 200AT 350A 460VAC


respectively

General Formula :

Full Load = HP ( 746 watts )K ( volts ) ( P.F. ) ( Eff. )

K = √3 for 3 phase , 1 for single phase P.F. = 0.80 to 0.85 Eff. = 0.80 to 0.90

CB Amp trip and fuse sizes are approximate selections for general installations

Full laod current

WIRE SIZE in sq.mm

WIRE SIZE in AWG



element



STANDARD SINGLE PHASE, 60HZ MOTOR DATA, 230VAC

HP KW Volts

1/6 0.1 2.2 2.0 14 15AT 6A 230VAC1/4 0.2 2.9 2.0 14 15AT 6A 230VAC1/3 0.3 3.6 2.0 14 15AT 10A 230VAC1/2 0.4 4.9 2.0 14 15AT 15A 230VAC3/4 0.60 6.9 2.0 14 15AT 20A 230VAC1 0.75 8 2.0 14 15AT 20A 230VAC

1.5 1.1 10 2.0 14 20AT 35A 230VAC2 1.5 12 2.0 14 30AT 40A 230VAC3 2.5 17 5.5 10 40AT 45A 230VAC5 4 28 8.0 8 50AT 70A 230VAC

7.5 5.5 40 8.0 8 70AT 100A 230VAC

STANDARD SINGLE PHASE, 60HZ MOTOR DATA, 115VAC

HP KW Volts

1/6 0.1 4.4 2.0 14 15AT 15A 115VAC1/4 0.2 5.8 2.0 14 15AT 15A 115VAC1/3 0.3 7.2 2.0 14 15AT 20A 115VAC1/2 0.4 9.8 2.0 14 15AT 25A 115VAC3/4 0.60 13.8 3.5 12 20AT 35A 115VAC1 0.75 16 3.5 12 30AT 40A 115VAC

1.5 1.1 20 3.5 12 40AT 50A 115VAC2 1.5 24 5.5 10 50AT 60A 115VAC3 2.5 34 8.0 8 70AT 95A 115VAC5 4 56 22 4 100AT 150A 115VAC

7.5 5.5 80 30 2 125AT 200A 115VAC

Full laod current

WIRE SIZE in sq.mm

WIRE SIZE in AWG



eleement

Full laod current

WIRE SIZE in sq.mm

WIRE SIZE in AWG



eleement

TABLE OF AMPACITY

PEC Table 3.10.1.16

TABLE 1Size of wire Ampacity

AWG mm² MCM THW @ 75°C14 2.0 4 1512 3.5 7 2010 5.5 11 308 8.0 16 456 14.0 28 654 22.0 44 852 30.0 60 1101 38.0 76 1250 50.0 100 14500 60.0 120 160

000 80.0 160 1950000 100.0 200 220

125 250 255150 300 280175 350200 400 330250 500 375300 600325 650 435380 750400 800 485500 1,000 540

AWG American Wire Gaugemm² Square millimeterMCM Area in circular mills

NOTE:Square millimeter to MCM multiply by 2MCM to Square millimeter divided by 2

TABLE II TABLE IIIFull Load Current in Amperes Full Load Current, Three Phase AC Motors ,

Single Phase AC Motors Induction Type, Squirrel Cage , Wound RotorHP 115V 230V HP 115V 230V 460V

0.167 4.4 2.2 0.5 4 2 10.25 5.8 2.9 0.75 5.6 2.8 1.4

0.333 7.2 3.6 1 7.2 3.6 1.80.5 9.8 4.9 1.5 10.4 5.2 2.6

0.75 13.8 6.9 2 13.6 6.8 3.41 16 8 3 9.6 4.8

1.5 20 10 5 15.2 7.62 24 12 7.5 22 113 34 17 10 28 145 56 28 15 42 21

7.5 80 40 20 54 2710 100 50 25 68 34

30 80 4040 104 5250 130 6560 154 7775 192 96100 248 124125 312 156150 360 180

CB Standard Ampere Ratings

15 50 125 35020 60 150 40025 70 175 45030 80 200 50035 90 225 60040 100 250 70045 110 300 800

OHMS LAW where:

E = I x R R = E E = volts ( V )I I = ampere ( A )

I = ER

COVERSIONS : 1 TON = 12,000 BTU 1HP = 746 watts1 TON = 4.7 HP 1 KW = 1,000 watts1 HP = 2,545 BTU/hr 1 KW = 1.34HP1 KW = 3,412 BTU/hr KVA to KW ( x 0.8 )

KW to KVA ( / 0.8 )

STANDARD MAGNETIC STARTERS DATA, NON-REVERSING, 3P, 60Hz

220VAC 440VACHP KW HP KW0.5 0.4 1.5 1.1 2.5A 1.7-2.5A Stop-Start1 0.75 2 1.5 3.6A 2.8-4.4A Stop-Start2 1.5 3 2.2 6.6A 5.2-8A Stop-Start3 2.5 5 4 9.0A 7-11A Stop-Start4 2.7 7.5 5.5 12.5A 9-16A Stop-Start5 4 10 7.5 15A 12-18A Stop-Start

7.5 5.5 15 11 22A 18-26A Stop-Start10 7.5 20 15 29A 24-34A Stop-Start15 11 30 22 42A 34-50A Stop-Start20 15 40 30 54A 43-65A Stop-Start25 19 50 37 67A 54-80A Stop-Start30 22 60 45 82A 65-93A Stop-Start40 30 75 55 105A 85-125A Stop-Start50 37 100 75 125A 100-150A Stop-Start75 55 120 90 125A 100-150A Stop-Start

150 110 180A 140-220A Stop-Start100 75 200 150 250A 200-300A (3E) Stop-Start150 110 300 200 330A 260-400A (3E) Stop-Start200 150 400 300 500A 400-600A (3E) Stop-Start

STANDARD MAGNETIC STARTERS DATA, REVERSE-FORWARD, DUAL SPEED (LOW AND HIGH), 3P, 60Hz

220VAC 440VACHP KW HP KW0.5 0.4 1 0.75 2.1A 1.7-2.5A S / R / F1 0.75 2 1.5 3.6A 2.8-4.4A S / R / F2 1.5 3 2.2 6.6A 5.2-8A S / R / F3 2.5 5 4 9.0A 7-11A S / R / F4 2.7 7.5 5.5 12.5A 9-16A S / R / F5 4 10 7.5 15A 12-18A S / R / F

R = ohm ( Ω )

RATED AMPERE

ADJ.OVERLOAD / HEATER RATING

PUSH BUTTON

RATED AMPERE


PUSH BUTTON

7.5 5.5 15 11 22A 18-26A S / R / F10 7.5 20 15 29A 24-34A S / R / F15 11 30 22 42A 34-50A S / R / F20 15 40 30 54A 43-65A S / R / F25 19 50 37 67A 54-80A S / R / F30 22 60 45 82A 65-93A S / R / F40 30 75 55 105A 85-125A S / R / F50 37 100 75 125A 100-150A S / R / F75 55 120 90 125A 100-150A S / R / F

150 110 180A 140-220A S / R / F100 75 200 150 250A 200-300A (3E) S / R / F150 110 300 200 330A 260-400A (3E) S / R / F200 150 400 300 500A 400-600A (3E) S / R / F

WYE-DELTA REDUCE VOLTAGE MAGNETIC STARTERS , 3P, 60HzWITH ADJ. OVERLOAD RELAY AND ADJ. TIMER AND AUTO-

TRANSFORMER

220VAC 440VACHP KW HP KW

7.5 5.5 12.5A 9-16A Stop-Start10 7.5 15A 12-18A Stop-Start

7.5 5.5 15 11 22A 18-26A Stop-Start10 7.5 20 15 29A 24-34A Stop-Start15 11 30 22 42A 34-50A Stop-Start20 15 40 30 54A 43-65A Stop-Start25 19 50 37 67A 54-80A Stop-Start30 22 60 45 82A 65-93A Stop-Start40 30 75 55 105A 85-125A Stop-Start50 37 100 75 125A 100-150A Stop-Start75 55 120 90 125A 100-150A Stop-Start

150 110 180A 140-220A Stop-Start100 75 200 150 250A 200-300A (3E) Stop-Start150 110 300 200 330A 260-400A (3E) Stop-Start200 150 400 300 500A 400-600A (3E) Stop-Start


respectively

RATED AMPERE


PUSH BUTTON



AIR COMPRESSOR MOTOR DATA @ 240VAC

Electrical power cable, AWG # 10 - 3 conductorMolded case circuit breaker, 240VAC,50AT, 3 Pole, 60Hz





Magnetic contactor, wye - start, delta-run,7.5HP,220VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (18-26A), pilot lamps ( red and green) stop - start push

button with enclosure

Magnetic contactor, wye - start, delta-run, 10HP,220VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (24-34A), pilot lamps ( red and green) stop - start push




Magnetic contactor, wye - start, delta-run,7.5HP,440VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (9-16A), pilot lamps ( red and green) stop - start push


ELECTRICAL FORMULAS FOR DETERMINING AMPERES, HORSEPOWER, KILOWATTS AND KILOVOLTS-AMPERES

ALTERNATING CURRENT ( AC ) SINGLE PHASE THREE PHASE, 4 WIRES THREE PHASE

KILOWATTS

KVA

HP OUTPUT

I - Ampere HP - Horsepower % Eff - Percent EfficiencyE - Volts KVA - Kilovolt-ampereKW - Kilowatts PF - Power Factor

DESIRE DATA

DIRECT CURRENT

I x E x PF 1,000

I x E x 2 x PF 1,000

I x E x 1.73 x PF 1,000

I x E 1,000

I x E 1,000

I x E x 2 1,000

I x E x 1.73 1,000

I x E x % Eff x PF 746

I x E x % Eff x PF 746

I x E x 1.73 x % Eff x PF 746

I x E x % Eff 746

AMP WHEN HP KNOWN

HP x 746 E x % Eff x PF

KW x 1,000 2 x E x PF

KW x 1,000 1.73 x E x PF

HP x 746 E x % Eff

AMP WHEN KW KNOWN

KW x 1,000 E x PF

KW x 1,000 2 x E x PF

KW x 1,000 1.73 x E x PF

KW x 1,000 E

AMP WHEN KVA KNOWN

KVA x 1,000 E

KVA x 1,000 2 x E

KVA x 1,000 1.73 x E

GENERATOR DATA @ 440VAC

KILOWATTS KILOVOLT-AMPERES AMPERES WIRE SIZE

30 37.5 49

35 44 57

40 50 66

44 55 72

45 56.2 74

50 62.5 82

60 75 99

RATED VOLTAGE

440VAC / 3Phase / 60Hz

AWG #6 / 14mm² - 3C


AWG #6 / 14mm² - 3C


AWG #6 / 14mm² - 3C


AWG #4 / 22mm² - 3C


AWG #4 / 22mm² - 3C


AWG #4 / 22mm² - 3C


AWG #2 / 30mm² - 3C

67 84 110

76 95 125

85 106 140

99 124 162

100 125 164

105 131 172

125 156 205

150 187.5 246

165 206 271


AWG #2 / 30mm² - 3C


AWG #1 / 38mm² - 3C


AWG #1/0 / 50mm² - 3C


AWG #2/0 / 60mm² - 3C


AWG #2/0 / 60mm² - 3C


AWG #3/0 / 80mm² - 3C


AWG #4/0 / 100mm² - 3C


125mm² / 250MCM - 3C


150mm² / 300MCM - 3C

175 219 287

200 250 328

225 281 369

230 287.5 377

250 312.5 410

260 325 427

275 344 452

350 437.5 575

400 500 657


175mm² / 350MCM - 3C


200mm² / 400MCM - 3C


250mm² / 500MCM - 3C


250mm² / 500MCM - 3C


300mm² / 600MCM - 3C


300mm² / 600MCM - 3C


380mm² / 750MCM - 3C


500mm² / 1,000MCM - 3C


200mm² / 400MCM - 6C

550 687.5 903

GENERATOR DATA @ 240VAC

KILOWATTS KILOVOLT-AMPERES AMPERES WIRE SIZE

15 19 49

18 23 56

20 25 66

30 37.5 99

35 44 115


380mm² / 750MCM - 6C

RATED VOLTAGE


AWG #6 / 14mm² - 3C


AWG #6 / 14mm² - 3C


AWG #6 / 14mm² - 3C


AWG #2 / 30mm² - 3C


AWG #1 / 38mm² - 3C

40 50 131

44 55 145

50 62.5 164

60 75 197

67 84 220

76 95 250

85 106 279

99 124 325

100 125 328


AWG #1/0 / 50mm² - 3C


AWG #1/0 / 50mm² - 3C


AWG #2/0 / 60mm² - 3C


AWG #3/0 / 80mm² - 3C


AWG #4/0 / 100mm² - 3C


125mm² / 250MCM - 3C


150mm² / 300MCM - 3C


200mm² / 400MCM - 3C


200mm² / 400MCM - 3C

105 131 345

125 156 411

150 187.5 493

165 206 541




250mm² / 500MCM - 3C


300mm² / 600MCM - 3C


400mm² / 800MCM - 3C


500mm² / 1,00MCM - 3C

Magnetic contactor, wye - start, delta-run,7.5HP,220VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (18-26A), pilot lamps ( red and green) stop - start push button with enclosure




Electrical power cable, AWG # 14 - 3 conductor

Magnetic contactor, wye - start, delta-run, 10HP,220VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (24-34A), pilot lamps ( red and green) stop - start push button with enclosure


Magnetic contactor, wye - start, delta-run,7.5HP,440VAC, 3 Pole, 60 HZ with adjustable timer ,adjustable thermal overload relay (9-16A), pilot lamps ( red and green) stop - start push button with enclosure

Molded case circuit breaker, 440VAC,20AT, 3 Pole, 60Hz





KEY OPERATION OF JOB ORDER

KEY OP SHOP SPECIFICATION

041 P/E

042 DES Provide sketches and technical assistance.045 S/S Do coordinating and monitoring work.046 SFTY Implement industrial safety and regulation.

120 REMOVAL OF UNIT400 INSPECTION OF UNIT420 SHOP WORK421 SHOP REPAIR OF CONTROLLER490 SHOP TEST520 REPAIR WORK ABOARDSHIP620 REINSTALLATION OF UNIT690 OPERATIONAL TEST

Conduct inspection, prepare workspec and material requisition.

KEY OPERATION OF JOB ORDER

SPECIFICATION

WIRE TABLEGauge No.

mm²Diameter Area in CIR MILS (D²)

AWG in inch IMIL 0.001 inch 0000 107.2195533 0.460000 211,600.00 000 85.02821169 0.409640 167,805.00 00 67.43230256 0.364800 133,179.00 0 53.47500208 0.324860 105,538.00 1 42.40872321 0.289300 83,694.20 2 33.63188406 0.257630 66,373.00 3 26.66986891 0.229420 52,634.00 4 21.15132497 0.204310 41,742.00 5 16.77315309 0.181940 33,102.00 6 13.30134585 0.162020 26,250.50 7 10.53631754 0.144200 20,818.00 8 8.365597947 0.128490 16,509.00 9 6.634957205 0.114430 13,094.00

10 5.260432529 0.101890 10,381.00 11 4.172295163 0.090742 8,234.00 12 3.308773558 0.080808 6,529.00 13 2.623932809 0.071961 5,178.41 14 2.078593073 0.064048 4,106.70 15 1.650226798 0.057068 3,256.70 16 1.308662481 0.050820 2,582.90 17 1.037838684 0.045257 2,048.20 18 0.823063001 0.040303 1,624.30 19 0.65185115 0.035867 1,287.10 20 0.517605698 0.031961 1,021.50 21 0.410477313 0.028462 810.10 22 0.325545323 0.025347 642.70 23 0.25814275 0.022571 509.54 24 0.204715367 0.020100 404.01 25 0.162354523 0.017900 320.40 26 0.128746362 0.015940 254.01 27 0.102100795 0.014195 201.26 28 0.080969451 0.012641 159.79 29 0.064210147 0.011257 126.78 30 0.050924537 0.010025 100.50 31 0.040389334 0.008928 79.71 32 0.032025254 0.007950 63.20 33 0.025399481 0.007080 50.13 34 0.020136813 0.006304 39.74 35 0.015969935 0.005614 31.52

36 0.012667717 0.005000 25.00 37 0.010047632 0.004453 19.83 38 0.006806225 0.003665 15.72 39 0.006314046 0.003530 12.47 40 0.005008681 0.003144 9.89

CONDUIT SIZE WIRE SIZE NO. OF CONDUCTORSAWG mm²

1 / 2 '' 6 14 112 3.5 212 3.5 3

3 / 4'' 1 38 18 8.'0 2

10 5.5 3

1 '' 000 80 16 14 28 8.'0 3

1 1 / 4 '' 400MCM 200 12 30 24 22 3

1 1 / 2'' 550MCM 275 10 50 21 38 3

2 '' 1,000MCM 500 1200MCM 100 2

000 80 3

2 1 / 2 '' 1,700MCM 850 1350MCM 175 2250MCM 125 3

3 '' 2,000MCM 1,000 1600MCM 300 2500MCM 225 3

3 1 / 2 '' NO ESTABLISHED STANDARD 1900MCM 450 2750MCM 325 3

4 '' NO ESTABLISHED STANDARD 11,100MCM 550 21,000MCM 500 3

Electrical Calculations

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