Yes but counterbalanced by the opposite current component obeying ohm law.
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Inductor has no high inrush current
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If you start at zero there is no opposite current component.
Voltage is not zero.
Fine. Still, di/dt is still finite.Voltage is not zero.
But look at this apparent contradiction: voltage is not zero but current zero through an inductor at the instant of switching on. It seems to violate Ohm law.
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Perhaps because Ohm's Law describes the behavior of current and voltage across a resistive component. When either capacitive or inductive reactance is added into the mix the voltage and current are related by time derivatives (leading to differential equations to solve) and you must know not only the instant value of the current and voltage but the recent history and near future of both together to be able to calculate the impedance.
If the waveforms are not periodic, and more strongly not sinusoidal, the solution requires more than simple arithmetic to derive.
Nature solves it much more elegantly. At the instant of switching on with maximum ac voltage across the inductor, there appear two current components: one regular ''ac'' component and another decaying dc component both obeying Ohm law but they are opposite and so add up to zero so that another natural law that current through an inductor can not change instantaneously is also obeyed!
It appears that this discussion is based on the inductance being constant. On devices such as solenoids and contactors, the initial inductance is quite low, then once the armature is fully engaged, the inductance rises. In this context, won't the initial current be higher than steady-state?
Oh! The decaying DC component does not obey Ohm law.:slaphead:
Where does this decaying dc component come from?
From the power source, of course.
A simpler method to handle these systems is the Laplace transform
transforms complex diff eqs into algebraic expressions
crunch and convert back
this allows switching functions, step and impulse, etc
without 'hanging a number' on these things it becomes too esoteric and no common inderstanging/ground can be defined imo
transforms complex diff eqs into algebraic expressions
crunch and convert back
this allows switching functions, step and impulse, etc
without 'hanging a number' on these things it becomes too esoteric and no common inderstanging/ground can be defined imo
gar
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Sahib:
I believe I know what you are trying to say, but it has nothing to do with Ohm's law.
Ohms law only relates to conductance (resistance), voltage, and current. It has nothing to do with power, inductance, capacitance, electron emission, or the cost of Boston beans in Gitmo.
The instantaneous current in a series circuit consisting of an AC sine wave voltage source, a switch, a resistor, and an inductor can be described by two terms.
An exponentially decaying L-R curve for the inductor and resistor added to the steady state L-R curve (which is a sine wave).
In the limit for a very long LR time constant relative to the AC excitation frequency this results in a peak current 2 times the ultimate steady state peak current. I do not consider this an inrush current, nor large.
For the very long LR time constant you can visualize this worst case as a sine wave current with either its most positive or negative occurrences at zero current, and turn on occurred at one of these peaks or valleys.
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Sahib:
I believe I know what you are trying to say, but it has nothing to do with Ohm's law.
Ohms law only relates to conductance (resistance), voltage, and current. It has nothing to do with power, inductance, capacitance, electron emission, or the cost of Boston beans in Gitmo.
The instantaneous current in a series circuit consisting of an AC sine wave voltage source, a switch, a resistor, and an inductor can be described by two terms.
An exponentially decaying L-R curve for the inductor and resistor added to the steady state L-R curve (which is a sine wave).
In the limit for a very long LR time constant relative to the AC excitation frequency this results in a peak current 2 times the ultimate steady state peak current. I do not consider this an inrush current, nor large.
For the very long LR time constant you can visualize this worst case as a sine wave current with either its most positive or negative occurrences at zero current, and turn on occurred at one of these peaks or valleys.
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What power source would that be before t(0) ?
Whatever that powers the inductor.
Ohm law applies under steady state condition. During a transient, it does not apply due to presence of exponential factor in the equation for current.
Not accurate ref post 36
it applies for complex function for i, v and z
exp, linear, diff eq, integral functions
you can derive the transient waveform
If you give a numerical example, it will be clarifying.
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