In reply to Alberto De Souza's message of Sat, 21 Mar 2015 23:16:09 -0400: Hi, [snip] >I completely agree. But I do not believe we are going to see large >differences between resistances, except in cases of heater failure. But >even if we see large variations of resistance between reactors, we can >measure it and take it into account in the input power.
The problem with this is that if there is a difference in input power you then need to convince people that your power to temperature conversion function is correct. And that will be a difficult row to hoe. >If we have >significant excess heat, it will be easily visible in the difference of >temperature. But, again, I do not expect large changes in heater resistance. > >Ergo, they can't be placed in series. >> They also can't be placed in parallel, since identical voltage over both >> would >> ensure a larger current through the coil with lowest resistance. >> > >The problem with this approach is that it is impossible to measure the >current on both reactors directly (not inductively) with the same >instrument without interrupting the current. This interruption, or the use >of two different ammeters, will give the skeptics exactly what they need to >question the results. I think you will find that it is much easier to convince them that two different ammeters are accurate, than to convince them that your calculations of temperature as a function of power are correct. All that you need do for the former, is allow them to test the ammeters themselves. > > >> In short each coil needs to be powered and controlled independently, and >> power >> consumption of each measured and logged to prove that the power >> consumption in >> both remains the same. >> > >It will be hard to convince the skeptics that there were no hidden sources >of power or errors of measurement in this case... There are none so blind as those who will not see. Don't bother trying to convince them. Just make sure that a reasonable person would be convinced, and be prepared to "fill in the blanks" in follow up experiments. > >I believe the assumption that the resistance of the coils will not change >is not a so hard assumption. The wires used for heater coils are designed >to withstand large temperatures and other harsh conditions without >significant variation of resistance. True, but they are not normally exposed to the rather extraordinary circumstances that take place within these cells. Better to remove the point of uncertainty to equipment outside the cell, where it can easily be verified, than leave it within the cell where it taints the results. Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
