--- On Wed, 7/15/09, John Berry <[email protected]> wrote:
> From: John Berry <[email protected]> > Subject: Re: [Vo]:Phase Angle Question Posed to Yahoo Q&A > To: [email protected] > Date: Wednesday, July 15, 2009, 10:09 PM > Replying only to the answer and only to > a part of the answer... > > Lenz law indeed insists the the induction is 90 degrees out > of phase, however if a current is allowed to flow in the > receiving coil then it's self inductance will cause the > phase to be pushed as far as 180 degrees out. I had come to a similar conclusion. But this should apply only to the receiving coil alone. Let us compare for the case if the receiving coil has an emf by wire connection, or what is termed line coupled. Then the impressed voltage occurs in time BEFORE the resultant amperage, and we hear the often bandied statement that the current is 90 degrees out of phase with the voltage. Actually as you have noted it could be pushed near 90 degrees out of phase if the effect is shown with a very large inductance, but this itself is dictated by the ratio of the resistance to the ohmic value of the inductive reactance, where if they are equal the current lags the voltage by 45 degrees, not 90 degrees. Now let us apply the same methodology to the case where the impressed emf is instead obtained by air core induction. If the lenz law implies that that the received currents are then 90 degrees out of phase with the currents of the source, we should also have to add the EXTRA amount of phase angle difference brought on by the time delay caused by the receiving coil's own self inductance, where as above you have noted then those currents might be as far as 180 degrees out of phase. However in the case of what might be termed resonant air core induction, the receiving coil then has an attached capacity in parallel, giving a sort of power factor correction where this EXTRA time delay is then negated. This can be noted by comparing the induced currents shown by the receiving coil alone and the higher volume of current attained when the receiving coil is given the correct capacity in parallel. > > > > If the phase were purely 180 degrees out of phase then no > energy would be lost in the primary if it didn't have > resistance. > This is why shorting generator coils sometimes reduces > mechanical loading compared to running a load and sometimes > it is even a lighter load than having the coil open circuit > as this reduces core losses. I have not heard of this before, doesn't seem to make sense at first glance. If we were speaking in terms of air core coils alone without attached capacities,(non resonant), then the presence of a shorted secondary in the vicinity of the primary would indeed reduce the primaries inductance and more current would issue through that primary. > > > However the phase will not do 180 degrees (pure reactive > current) or 90 degrees (pure voltage, no current) but > somewhere in between. I still maintain that for the ideal conditions brought upon by the correct attachments of capacities on both sides, the reaction should be very close to 90 degrees apart. Probably the best way to determine the truth here would be to make a dual channel scoping of both signals. > A transformer is a little different in that unlike a > generator the inductive field generally grows stronger and > so if you short the secondary more current will flow through > the primary to the point of destruction, however if the > current into the primary is limited then it too will act in > the same way and a shorted secondary could possibly pull > less power from the primary that even an open secondary! There is some truth here that has to do with the principle of maximum energy transfer, but I doubt whether a shorted secondary would pull less power then an open one. If we determine the internal resistance of the source of emf; and then give that ohmic value as the load, maximum energy transfer should take place. This then implies that if smaller and smaller ohmic loads going down near zero ohms are then tested; the theorem or principle implies that LESS energy will be transferred and not more. This kind of problem was shown when a 3 phase high voltage transformer was placed between the output and the alternator input. At first I was perplexed because in that scenario no ferrite heating effects were noted! One would ordinarily think that more heating effects would be noted, not less to nothing. The problem then becomes the fact that the new source of emf from the transformer secondary has an internal resistance near 140 ohms which changes everything. In the new situation for the transformer to show its 19 fold voltage rise, the ohmic loads on the output need to be many times this internal resistance value of 140 ohms. The ohmic ferrite load in that case is low enough to drive the circuit UNDER the correct ohmic load for maximum energy transfer. If no ferrite conduction takes place BETWEEN the outer Delta Series Resonances, their own internal resistance of only ~ 2.4 ohms acts as the load; which is far below the 140 ohm internal resistance of the secondary. It seems entirely possible however to use a different resonant circuit to initially cause the ferrite heating effect where its resistance then decreases from thousands of ohms to a couple hundred of ohms, and THEN quickly change the circuit to the transformer one before the ferrite looses significant heat. It would seem that this would be the only way to employ the transformer for this scenario. A great deal of confusion is brought on by the fact that the load between the DSR's,(Delta series resonances) is not the same thing as the load of the entire circuit that enables the voltage rise. In this case attaching a short between the DSR's drives the entire circuit towards three tank circuits connected in WYE which the source sees as a maximum impedance. In that condition the transformer can act as it should. To show this the ferrite block sandwiched between steel rulers can be placed underwater and after baking soda electrolyte is added a somewhat convincing demo of resonant electrolysis can be made. In that situation ten times the current will exist across the cell then any of the individual stator line delivery currents, where this effect is brought on by the resonant rise of amperage in the circuit, which occurs when the circuit is operated towards the direction of showing a parallel resonance, instead of a series resonant one that delivers voltage rise instead. However a new problem then poses itself from the fact that the primary then consumes more amperage then it should proportionally to the amount of voltage rise made by the transformer itself. No energy gain is noted. Sincerely HDN
