Claimed OU circuit of Rosemary Ainslie

[MileHigh]

TK:

For starters for everyone:  The tough-talking trash talk from me is over, the rebut was done and it's time to move on.

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I'm still on the load inductance thing...what is up with that? If you look back several pages you might see (if he hasn't removed it) a picture where he puts up another bad 555 circuit and says that the load inductance must be "as high as possible" for a 10 ohm resistor. Yet Ainslie used, she claims, 0.00864 milliHenry, and Aaron's Ohmite is probably 0.150 - 0.200 milliHenry...a not insignificant difference...
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Aaron is incorrect here.  This one is easily explained with a narrative.  You look at your shunt current waveform, and see the exponential rise in the current waveform.  So, if you put in a much larger inductor, but assume the resistive part of the coil-resistor remains the same 10 ohms, what do you get?  You get the same rising current waveform but it takes longer to rise, i.e.; a longer time constant.  So what's the result?

Larger inductance means longer times to charge and also discharge the energy into/out of the coil-resistor.   This means that your total cycle period has to go up and therefore your pulse frequency has to go down. We are assuming that you want to tweak the MOSFET on and off pulse widths to match the timings of the larger coil.  Larger inductance gives you more energy per discharge, but with a trade-off of less discharges per second.  It looks like any possible power gains with a larger inductive component would be marginal at best.

Is this all starting to sound like a zero-sum game to you?  It does to me.  Without doing any real math, just following the narrative, it looks to me like there is no reason to get excited about the amount of inductance in the coil-resistor.

It just occurred to me there is one nice little benefit from more inductance:  less MOSFET switching, less power lost in the MOSFET.

MileHigh

PS:  There is another "advantage" with a larger inductive component.  With a large inductor the current starts to flow more slowly, so you can get a better ratio of inductive stored energy to lost energy dissipated in the resistor when you swtch off the MOSFET.  You can "chop early" and start to increase the pulse rate again.  BUT, the energy per discharge pulse goes down again.

The truth though is that you can do the same thing for any coil value, the smaller the coil the shorter the "chop time" has to get to maintain the same ratio of inductive stored energy to lost energy dissipated in the resistor before you discharge.

[MileHigh]

AllCanadian:

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Let's see both Michael's circuit and Rosemary's circuit --
1)charge an inductive resistance with current to saturation
2)disrupt the source current at a low duty cycle
3)the disruption to current produces an inductive discharge
4)the inductive discharge then charges a resistance producing heat
Yes I can see how you came to the conclusion that they have nothing in common, LOL.
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You are making a valid point.  I should have added more commentary and fleshed out my point.  Certainly both setups charge a coil and capture the discharge energy, but after that, there is not too much in common between them.  Rosemary's circuit makes a claim of COP 17, Michael's circuit makes a claim of reduced electricity bills.  Yes, you can "trick" the power company (unless they are sniffing out "power factor offenders" on the block) and soak up Joules of energy and then discharge that energy through a second resistive element and fool the electrical meter.  That is not a claim of COP 17, that is not even a claim of COP > 1, it's just a claim of diverting mains energy into an inductor and using that as heat energy.  Do you get me now?  I was just too tired to write it all out.

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If the Amps and volts were imaginary "phantom power" then I wonder what produced the inductive discharge when the source was disconnected. This is quite a predicament we have because something must have charged the inductance to produce the magnetic field which collapsed producing the very real inductive discharge which heated michael's secondary resistance, Im going to take a wild guess and say it was current and volts(power) from the source. Maybe you can clarify your statements for me, or perhaps someone else here can?
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It is inded the the voltage times the current going into the coil that produces the reactive power.  Suppose at one instant in time the voltage drop through the resistive part of the coil-resistor is 1 volt and it's 10 volts for the coil part.  Since power is proportional to the square of the voltage, the coil is absorbing 100 times more power than the resistor is disipating - at that instant in time.

Normally the reactive power gets pushed back into the mains through one full cycle for net zero energy transfer.  In both Michael's and Rosemary's case that does not happen, the coil accumulates reactive energy, and then the MOSFET or TRIAC switches off and it it pumped into the load.  Michael's circuit is "stealing" the "return cycle" for the reactive power.  In Rosemary's case there is no return cycle for the reactive energy, it has to go somewhere when the MOSFET switches off.

MileHigh

[0c]

In Rosemary's case there is no return cycle for the reactive energy, it has to go somewhere when the MOSFET switches off.

In Paris Hilton's immortal words: "That's Hot"!

[Hoppy]

Hoppy,

Out of curiosity, what was the DC voltage required to obtain your 7.83W control test?

Was the MOSFET and shunt resistor in the circuit?

Thanks,
.99

Voltage 8.7V. Mosfet and shunt resistor not in control test circuit.

Hoppy

[Hoppy]

Hey I just lost my dual-citizenship.  Aaron threw a small hissy-fit and kicked my ass.  Funny, it doesn't hurt.

Hoppy:  I think that you are looking good and it is just measurement error.  There has got to be a limit to how good the analog meter does averaging to measure the current consumption.  The higher frequency components in the current waveform probably can't be averaged out, and hence you are measuring less power than there really is.  There are work-arounds to allow you to make pretty accurate measurements without having a DSO through, I even posted one in the Energetic Forum.

I have to answer a lingering question from across the great divide (one tab away) for Quantum, Joit, and Harvey:  Michael's circuit converts the resistive load of the water heater into a reactive load using the triac/heater coil/diode/second heating element.  Most older household electricity meters can't measure reactive power, hence Michael's electrical costs go down.  That's probably a legal loophole in most areas and you can't be accused of stealing electricity, just guessing.  As you can see, it has absolutely nothing to do with Rosemary's circuit.

MileHigh

You are correct about analogue meter measurements. This simple measurement of my circuit was just to show that there is no big difference between the power consumed in the circuit compared to the 'control', assumed the measurements are interpreted correctly, which clearly is not the case from Rosemary's COP17 conclusion.

Hoppy