Elec Class

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Solved exercise · level 4 of 5

Cross-section of a garage line

Skills: Build, Calculate

Statement

A garage (radiator R₁ of 4000 W and 100 W lamp L1, at 220 V) is supplied through a copper line of 20 m (F1 = there and back, 40 m). It must receive at least 200 V.

Choose for F1 the smallest suitable cross-section among 1 · 1.5 · 2.5 · 4 · 6 · 10 · 16 · 25 mm².

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

2 hints from Bastaya available in the lab
Solution

I ≈ 18.6 A; max R_line = (220 − 200) / 18.6 = 1.07 Ω; S ≥ 0.017 × 40 / 1.07 = 0.636 mm² → standard cross-section 1 mm². V1 then reads 208 V.

Course sheet of the chapter : Resistor networks

This chapter is covered by the paths: 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

Del
delete
R
rotate
C
chip brush
Esc
cancel
wheel
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fit the board
drag background
pan

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