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Solved exercise · level 3 of 5

Powers of a coil

Skills: Calculate

Statement

A coil of resistance R = 20 Ω and inductance L = 100 mH is supplied at 230 V, 50 Hz. What apparent, active and reactive powers does it absorb?

Apparent power S = U · I.

Parametric exercise: the values change with every draw; these are one example.

1 hint from Bastaya available in the lab
Solution

L·ω = 31.4 Ω; Z = 37.2 Ω; I = U / Z = 6.18 A; S = U · I = 1420 VA; P = R · I² = 763 W; Q = L·ω · I² = 1200 var; check: S = √(P² + Q²).

Course sheet of the chapter : AC power

This chapter is covered by the paths: General electricity, ISL-oriented exercises

Other exercises of the chapter

Simulated time00:00:00
Q = I·t-
W = P·t-

Circuit diagram CEI 60617

How does it work?

Each big hole is a circuit node: you push one leg of a component into it. The 4 small holes around it are connected to it: chips and leads plug in there.

  1. Place a component Drag it from the palette: it snaps onto the grid. R rotates it.
  2. Bridge neighbouring holes Pick the jumper chip (or C) and drag on the board: bridged holes become a single node.
  3. Draw a lead For long links and the power supply: from one big hole to another, or to a terminal.
  4. Close the loop The circuit is solved live (Ohm, Kirchhoff) and the diagram follows.

Shortcuts

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C
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