MH's ideal coil and voltage question

[tinman]

@tinman

Wow, this is playing out to be one hell of drama here.

I cannot believe if you knew what the actual question meant, you would have had a problem answering it then. The only reason I backed you up in this is because I saw this question as to ambiguous and did not openly imply 6 separate MANUAL settings of voltage. In my book there was no other VALID reason to object to it since we all new it was under ideal conditions. We know ideal conditions do not exist but the way the question was asked was in my book, deceptive in the process, not in the substance.

So good luck then.

wattsup

Here is the problem with being able to answer the question using ideal components.

1- if the coil is ideal,then why would not the CEMF be ideal to the EMF that created it?
If the CEMF is ideal,and equal to the EMF,would current ever flow through the coil?.

2- If the voltage source is ideal,it cannot dissipate power. If it absorbs power,and cannot dissipate power,why dose it not store that power as MH says?.

MH says an ideal voltage source can deliver energy,but dose not contain any energy.
He then says that an ideal voltage source can absorb power,and that power just is gone-disappears,no longer exist.

To many holes in the question when ideals are included.
To many holes in MHs explanation.
To many other EE guys agreeing with some of these MH paradoxes that are nonsense.


If we are to come to some sort of correct answer,then these nonsense's need sorting.

To look at the question again

You have an ideal voltage source and an ideal coil of 5 Henrys.  At time t=0 seconds the coil connects to the ideal voltage source. For three seconds the voltage is 4 volts.  Then for the next two seconds the voltage is zero volts. Then for two seconds the voltage is negative three volts, and then for the next six seconds the voltage is 0.5 volts.  Then after that the voltage is zero volts.
What happens from T=0 when the ideal voltage is connected to the ideal coil?.

It is clear that an ideal voltage source delivers a volatge selected by the user,and will maintain that voltage no matter what the load. The voltage value can only be determined and change by the user--not the load.

The user(MH) has selected a voltage of 4 volts to be placed across the ideal coil,for a period of 3 seconds. After the first 3 seconds, he then changes that voltage value to 0 volts,for a period of 2 seconds. After that two seconds is up,he inverts the polarity,and selects a voltage value of 3 volts,for a time period of 2 seconds. After that period of 2 seconds is up,he then selects a voltage value of 500mV for 6 second's. As he dose not mention !negative! at this point,we can assume that the voltage polarity at this point in time,is now back to the original polarity-being the positive polarity. After this 6 second time period,the voltage value is then selected to be 0 volt's.

I do not see the problem in understanding the voltage wave form that would be associated with this question. What i do question is would that actually be the case,and would this ideal circuit follow the same rules as real world components?.


Brad

[poynt99]

He also stated -but what happens to  it?.

Yes, that is a good question too.

But I'd like your answer on the concept that the source can and will absorb energy from the inductor.

Do you agree or disagree?

[minnie]

   What's the problem?
    I.V.S. able to supply/absorb any amount of current.
    The current through I.V.S. Completely under the control of the external circuit.

[partzman]

I know some here and perhaps many that have followed this thread think that this is some kind of futile exercise that has no bearing on our OU efforts so let's get back to work!

Well, consider this- If I should see some kind of odd result in my prospective OU creation, how do I determine if the anomaly I see is the result of some newly discovered function or simply the result of conventional functions that slipped past me because of my lack of understanding. This has happened to me more times than I would like to admit and it is the reason I strive to understand the basics so I will be able to recognize a true anomaly if and when it occurs.

I believe that this was/is the intention of MH when he proposed the original problem as well as others who have contributed along the way.  Whether the problem uses ideal components as originally stated or real world components as later stated, the resulting differences are insignificant. The point is, do I understand how to solve this problem or not?

partzman

[tinman]

Yes, that is a good question too.

But I'd like your answer on the concept that the source can and will absorb energy from the inductor.

Do you agree or disagree?

I cannot agree to the ideal voltage source being able to absorb energy if it cannot contain it.
If any energy is absorbed by the ideal voltage source,and that ideal voltage source dose not dissipate energy,then the energy must now be contained in it(the ideal voltage source).

I cannot agree with MHs statement that the energy is just gone-disappears.
MHs question consists of two components only--the ideal voltage source,and the ideal inductor. He has made this apparent many times when he has stated that EMJ and Wattsup could not answer a simple question that involved on two components.
MH also states that the ideal voltage source can deliver energy,but dose not contain energy.

At T=5s, what would the solution below read?
And then again at T=7s,what would the solution below read?.

Brad