Rosemary Ainslie Circuit Demonstration, June 1 2013

[TinselKoala]

I forgot to note Yet Another discrepancy in the Figure 5 shot from the most recent edit of Ainslie's Paper 1 that I downloaded from her forum site.

The description says the "switching period was set to 684 ms" that is, 684 milliseconds .... but the scope's horizontal timebase is set to 500 microseconds per horizontal division.  A look at the traces shows that they might be showing a period of 684 microseconds, abbreviated μs or us. This is excusable as a typo, maybe ..... in a first draft of the manuscript. It is not excusable in the most recent edit (of many) or the "official publication" which is really just a posting on Rossi's JNP blog.

[TinselKoala]

I=V/R.
Voltage drop across "shunt" during Q1 ON times-- essentially DC---  is about 0.75 V, and the "shunt" is 0.25 Ohms. Therefore, the current flowing in the system is 0.75V/0.25Ohm == 3.0 Amperes. 

Hardly what I would call a "limited amount of current flow", since it is near the maximum that can be attained with a battery voltage of 49.5 volts and a total circuit DC resistance of a bit over 14 Ohms.

P=I²R.
With 3 amps going through the Q1 mosfet at a duty cycle of about 20 percent, the mosfet will be dissipating _at least_ (0.20) x (3 amps) x (3 amps) x 2 ohms Rdss == 3.6 Watts average. It will warm perceptibly but won't be stressed, even on the tiny original heatsink. And this is why they always limit the batteries to four or less when demonstrating the "high heat" mode: to keep the current in Q1 low so it doesn't overheat.

With 74 volts the mosfet should be conducting I = V/R = 74V/14 Ohms == 5.28 amps. At a 20 percent duty cycle it will be dissipating _at least_ (0.20) x (5.28 A) x (5.28 A) x 2 ohms Rdss == a bit over 11 Watts average. It will get hot but not in danger of failing completely if the run is short. If the frequency is lowered so that the mosfet doesn't have a chance to cool, as in the 160 second period used in Figure 1 with 16 or 18 seconds ON, the mosfet will have to dissipate over 50 Watts during that long ON time.... and will likely fail. Ever put your finger on an operating 50 Watt light bulb? Now imagine that power in a package the size of a TO247 device package.

All this is without considering the oscillations, which do warm the Q2 mosfets a small amount but don't affect the Q1.

[TinselKoala]

Good luck for those tests.  We'll probably be doing our demo at 6.00 pm on Saturday.  But I'll firm up on this later this evening and will post it in my 'debunking troll spin' thread.

"this evening" being yesterday, Tuesday evening. So where's the "firmed up" date and time posting, today, almost Thursday morning? Nowhere, that's where.

Of course, this is what she posted there on June 24th:

We are doing this demonstration for the EXCLUSIVE PURPOSE OF PROVING FIG 3 PAPER 1.  That demonstration is intended for 4.pm Central African Time - Saturday 29th JUNE.  If I am hospitalised - or if our presenter is hospitalised or for various reasons is unable to attend - then - under all reasonable circumstances - we reserve the right to delay that demonstration.  BUT - no such delay is envisaged - God willing.

That's the same thing she said at an earlier promised demo date that she snivelled on: "God willing". And apparently he wasn't then, so why should he be willing this time?

Of course, if she is hospitalized....... maybe I'll send her some flowers.










NOT.

[SeaMonkey]

...right now we are dealing with the absence of current in the Q1 mosfet even though it is clearly getting sufficient gate drive to turn on, as shown in Ainslie's Figure 3 scopeshot.

Do you have anything specifically to say about that topic?

Whenever possible, rather than replicating an
exact duplicate of whatever circuit is being
investigated, I prefer to focus on the characteristics
of the circuit which may prove beneficial.  Then I
set out to accomplish whatever switching may be
necessary to produce the desired "waveforms"
in the most efficient and least complicated fashion.

In many cases the original circuit contains fatal
flaws which compromise device reliability.  In those
cases I'll improvise liberally to find necessary
corrections/solutions.

Once the desired operational parameters are gleaned
then it is possible to duplicate those, with any needed
"tuning," to optimize the effects.

For those reasons I avoid exact replications.

[TinselKoala]

Right. That's a "no", then. You are not qualified to comment on Ainslie's circuit because you have not built it nor explored its various aspects in simulations or circuit theory analysis.

OK, then.... do you have some of your OWN work to talk about, that demonstrates anything at all valid or relevant to this discussion of Ainslie's upcoming alleged demo of the Figure 3 scopeshot?

Allegedly upcoming, that is. I will be very surprised if she -- or rather, "her presenter"..... actually pulls it off on Saturday.