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For K-12 Students · Fault Analysis

Fault Analysis for a relay

Built for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework. Simulate a relay live below — adjust the inputs and watch it respond, right in your browser.

Three Phase

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Three-Phase PowerLive

the grid's backbone

Controls

Speed1×

Presets

Line voltage (V)

Line current (A)

Power factor

Three-phase power delivers energy on three conductors carrying sinusoids 120° apart, so total power is constant and motors self-start. Line and phase voltages differ by √3, and real power is P = √3·V_line·I·cosφ. The power factor cosφ measures how much current actually does useful work.

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Data Inspector

Phase voltage231 V

Real power P12.5 kW

Apparent S13.9 kVA

Reactive Q6.0 kVAR

Governing equation

P = 3 V_{L} I cos φ = 3 \times 400 \times 20 \times 0.9 = 12.5 kW

Reading this result: Real power P = √3·V_line·I·cosφ = 12.5 kW, trailing the 13.9 kVA apparent power by the angle φ = 26°.

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RLC Circuit

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RLC Circuit StudioLive

series RLC step response

Controls

Apply a step voltage to a series RLC circuit and watch charge and current respond — under-, over-, or critically damped.

Presets

Resistance R

Inductance L

Capacitance C

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Data Inspector

Damping ζ0.750

Regimeunderdamped

ω₀1.000

Governing equation

1 \overset{q}{¨} + 1.5 \overset{q}{˙} + \frac{q}{1} = V_{0}, ω_{0} = \frac{1}{L C} = 1.000, ζ = \frac{R}{2} \frac{C}{L} = 0.750

Reading this result: ζ = 0.750 < 1: underdamped. With ω₀ = 1.000 rad/s the charge overshoots and rings, oscillating while it decays toward its steady value. Lower ζ means more ringing.

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Frequently asked questions

Is this good for k-12 students?: Yes — this version of "Fault Analysis for a relay" is framed for k-12 students learning it in middle or high school. Watch the idea come alive with plain-language steps and everyday examples — perfect for projects and homework.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.