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Resistive-type heating appliances and incandescent lamps (conventional or halogen)

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See also "Lighting circuits" for more details

The current demand of a heating appliance or an incandescent lamp is easily obtained from the nominal power Pn quoted by the manufacturer (i.e. cos φ = 1) (see Fig. A5).

Nominal power (kW) Current demand (A)
1-phase

127 V

1-phase

230 V

3-phase

230 V

3-phase

400 V

0.1 0.79 0.43 0.25 0.14
0.2 1.58 0.87 0.50 0.29
0.5 3.94 2.17 1.26 0.72
1 7.9 4.35 2.51 1.44
1.5 11.8 6.52 3.77 2.17
2 15.8 8.70 5.02 2.89
2.5 19.7 10.9 6.28 3.61
3 23.6 13 7.53 4.33
3.5 27.6 15.2 8.72 5.05
4 31.5 17.4 10 5.77
4.5 35.4 19.6 11.3 6.5
5 39.4 21.7 12.6 7.22
6 47.2 26.1 15.1 8.66
7 55.1 30.4 17.6 10.1
8 63 34.8 20.1 11.5
9 71 39.1 22.6 13
10 79 43.5 25.1 14.4

Fig. A5Current demands of resistive heating and incandescent lighting (conventional or halogen) appliances

The currents are given by:

  • 3-phase case: \mbox{Ia}=\frac{\mbox{Pn} }{\sqrt3\mbox{U} } [1]
  • 1-phase case:\mbox{Ia}=\frac{\mbox{Pn} }{\mbox{U} } [1]

where U is the voltage between the terminals of the equipment.

For an incandescent lamp, the use of halogen gas allows a more concentrated light source. The light output is increased and the lifetime of the lamp is doubled.

Note: At the instant of switching on, the cold filament gives rise to a very brief but intense peak of current.

Notes

  1. ^ a b Ia in amps; U in volts. Pn is in watts. If Pn is in kW, then multiply the equation by 1,000.