Rosemary Ainslie circuit demonstration on Saturday March 12th 2011

[Rosemary Ainslie]

Cat, Fuzzy, MaNag - has it not yet occurred to you guys to wonder why it is that I so patiently and repeatedly answer your posts?  Why I take the trouble?  It would be so easy to simply walk away from here.  I read somewhere on these threads that 'if you're going to wrestle with pigs - you'll both get dirty.  But the pig will enjoy it'.  Something like that.  Well.  I know that it does my 'name' no good.  But I'm not interested in my name.  And it does nothing to advance my popularity.  But I'm not interested in my popularity.  Here's what it achieves.  You guys are actually giving me an almost infinite variety of ways to attest to the truth of the claim - precisely because you keep challenging it.  And I WONT TIRE of defending it.  EVER.  There's a mission involved here.  And I'm equal to it - while I've still got some kind of life in me.  More than equal to it.

So.  Really.  From the bottom of my heart.  Thank you.

Rosemary

[poynt99]

With the actual capacitor value:

Capacitor start voltage = 37.6V @ 17:47:47
Capacitor end voltage = 32.0V @ 17:48:32
Voltage drop over the 45 seconds = 5.6V
Capacitor = 2x 150,000uF, 40V, in parallel

Evidently the circuit functioned normally for a short period, and there was no recharge.

The energy used then is: 1/2 x 300,000uF x (37.6² - 32²)
= 58.46J, and the average power supplied over the 45 seconds = 1.3W.

.99

[Rosemary Ainslie]

With the actual capacitor value:

Capacitor start voltage = 37.6V @ 17:47:47
Capacitor end voltage = 32.0V @ 17:48:32
Voltage drop over the 45 seconds = 5.6V
Capacitor = 2x 150,000uF, 40V, in parallel

Evidently the circuit functioned normally for a short period, and there was no recharge.

The energy used then is: 1/2 x 300,000uF x (37.6² - 32²)
= 58.46J, and the average power supplied over the 45 seconds = 1.3W.

.99

Poynty?  As I understand it Joules relates to the energy dissipated as work.  And that resistor of ours was measuring over 150 degrees centigrade.  Ambient at  about 16 degrees centigrade.  Surely that's got to be factored in?  Somewhere?  Temperature over ambient indicated 33 watts dissipated or thereby.  The downside of this value is that the temperature was still climbing fast.  We never tested it to the duration. Frankly, if I'd known that you could determine the actual energy dissipated over this period I'd have kept closer record.

Regards,
Rosemary

Added.

[poynt99]

Groundloop - the caps were 2 x 40 volt 150 000 ? micro farad in parallel.  I hope I've got that right. 

Apparently the circuit leads were directly across the caps.  So, I guess the caps must have been in parallel to the batteries.

If the battery voltage was 60V, then it is highly unlikely the batteries were connected throughout the test. 40V capacitors would not cope too well with 60V across them (they tend towards explosion under these conditions), and hopefully your assistant knew this. Perhaps he had only 3 batteries connected in order to charge the capacitor to about 36V.

Which means that the test was a definite FAIL.  The caps DO NOT WORK.

The circuit did work (oscillate) until the voltage dropped to a certain level.

What stuck me is that the waveform just COLLAPSES.  Unless we should have been using different caps?  Not at all sure.  Frankly I never thought that a cap would work.  I just don't know why it should.

It stopped oscillating because the circuit is not optimized to work at lower voltages. It's a matter of tweaking the circuit.

That test, at least, is put to bed.

Actually, no.

.99

[Rosemary Ainslie]

If the battery voltage was 60V, then it is highly unlikely the batteries were connected throughout the test. 40V capacitors would not cope too well with 60V across them (they tend towards explosion under these conditions), and hopefully your assistant knew this. Perhaps he had only 3 batteries connected in order to charge the capacitor to about 36V.

Yes it was only connected to 3 batteries.  No he is NOT MY ASSISTANT.  GOLLY.  He's a professional engineer.

The circuit did work (oscillate) until the voltage dropped to a certain level.

Yes.  It did.  Momentarily. 

It stopped oscillating because the circuit is not optimized to work at lower voltages. It's a matter of tweaking the circuit.

He's satisfied that it won't continue to oscillate.  And I'm happy to rest on his advices.

Rosemary