Labo Élec
electrical lab simulator
Exercise from the chapter "Ohm's law & resistance"
Level 3 of 5 · Skills: Calculate
A machine winding has a resistance of 18 Ω at 25 °C. After some running time it has become 27.1 Ω. What is the temperature rise? (α = 0.0045 /°C)
Rθ₁ = 18 Ω · θ₁ = 25 °C · Rθ₂ = 27.1 Ω · α = 0.0045 /°C
Parametric exercise: the values change with every draw; these are one example.
Guided problem in 4 steps: unknown, formula, units, data, result.
θ₂ = 150 °C (method of the previous exercise); Δθ = θ₂ − θ₁ = 150 − 25 = 125 °C. This is how the heating of a winding is measured without a thermometer.