What causes of voltage runaway in series LC resonant circuit?

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Discussion Overview

The discussion revolves around the phenomenon of voltage runaway in series LC resonant circuits, exploring the underlying causes and conditions that lead to this effect. Participants examine both theoretical and practical aspects, including the role of resistance and external excitation in real-world scenarios.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the mechanism behind the exponential rise in voltage, suggesting possibilities such as distributed capacitance acting as a voltage multiplier or voltage wave reflection due to impedance mismatch.
  • Another participant asserts that voltage runaway primarily occurs in simulators without resistance, noting that real series tuned circuits include resistance which affects voltage magnification, defined as the ratio of inductor reactance to resistance.
  • A third participant expresses frustration with simulators, implying they contribute to misconceptions about circuit behavior.
  • Another participant counters that voltage runaway can occur in real circuits with external excitation, citing an example from a high voltage electrical substation where overvoltage conditions led to component damage.

Areas of Agreement / Disagreement

Participants express differing views on the conditions under which voltage runaway occurs, with some emphasizing the role of simulators and resistance, while others highlight real-world scenarios where similar effects can manifest. No consensus is reached on the primary causes.

Contextual Notes

Participants note the importance of resistance in real circuits and the limitations of simulations, but the discussion does not resolve the assumptions or definitions surrounding these concepts.

Who May Find This Useful

Individuals interested in circuit design, electrical engineering, and the behavior of resonant circuits may find this discussion relevant.

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I'm trying to understand why the voltage in a series LC resonant circuit exponentially rises?

Can anyone explain exactly what happens that creates the effect?

I've been wonding if it the distributed capacitance of L becomes a voltage multiplier, or if it is a voltage wave reflection from a imperfectly matched impedance?
 
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This only happens in simulators and only if you specify a circuit with no resistance in it.

Real series tuned circuits have some resistance.

The voltage magnification is equal to the ratio of XL / R (where XL is the reactance of the inductor) and this value is reached almost instantly.
 
Death to all uncontrolled simulators!
They have a lot to answer for.
 
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I wouldn't exactly say this can only happen in simulators - a tuned LC Ckt with external excitation ( like a radio signal) can easily generate enough V to damage the components. Had this happen once in a High Voltage Electrical substation where a parallel feed (not electrically connected) was able to excite an isolated portion of the substation - to Overvoltage condition.

When the isolated section ( now damaged by overvoltage) was re energized the result was - well - interesting...
 

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