WELDING TRANSFORMERS



WELDING TRANSFORMERS:

WELDING CURRENT, WELDING LOAD (ARC VOLTAGE) KW RATING HP RATING

Sl.No.

Welding current Amps

Welding load Voltage (Arc Voltage) Volts

K.W. rating K.watts

H.P rating H.P power

H.P. Rating Continuous Maximum

1

150

26

3.9

5.23

3.19

2

200

28

5.6

7.51

4.5

3

250

30

7.5

10.05

6.03

4

300

32

9.6

12.87

7.72

5

350

34

11.9

15.95

9.57

6

400

36

14.4

19.3

11.58

7

500

40

20

26.81

16.09

8

600

44

26.4

35.39

21.23

           

The above load voltage are based on the formula V = 20 + 0.04 where V is the voltage & I is the load current 2. K.V.A Rating of welding Transformer.

Sl.No

Welding current Amps

60 Volts

K.V.A. rating for O.C.V

70 Volts

80 Volts

100 Volts

1

150

9.0

10.5

12.0

15.0

2

200

12.0

14.0

16.0

20.0

3

250

15.0

17.5

20.0

25.0

4

300

18.0

21.0

24.0

30.0

5

350

21.0

24.5

28.0

35.0

6

400

24.0

28.0

32.0

40.0

7

500

30.0

35.0

40.0

50.0

8

600

36.0

42.0

48.0

60.0

3. Power factor of Welding Transofomer at different Current rating for different D.C Voltage

Sl.No

Welding current Amps

60 Volts

Power Factor - Cost of O.V.C

70 Volts

80 Volts

100 Volts

1

150

0.433

0.371

0.325

0.260

2

200

0.567

0.400

0.350

0.280

3

250

0.500

0.429

0.375

0.300

4

300

0.533

0.457

0.400

0.320

5

350

0.566

0.486

0.425

0.340

6

400

0.600

0.514

0.450

0.360

7

500

0.667

0.571

0.500

0.400

8

600

0.733

0.628

0.550

0.440

IMPORTANT NOTE

1

Welding Transformers are generally rated in arc current rating viz 150 Amp. 200 Amps. 300 Amps. And not in K.V.A or H.P

2

The average duty cycle of Welding Transformers as per I.S.S.No. 1851 - 1975 is 60% for hand welding.

3

The continuous rating may be taken 60% of the maximum current rating

4

In some machines the maximum current limits is to be used 35% duty cycle or even for as low as 20% duty cycle.

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