Jim Yanik wrote:


I fail to see how the separate thermocouples outputs will be
"averaged",because any individual TC cannot rise in output,as all the
others parallelled will prevent any rise in voltage.Or current would flow
from a higher V to a lower one,just as if you wired batteries of different
voltages together,you end up with circulating currents until all cells are
of equal voltage..
Seems to me that parallelling them is only for the possibility of an
individual thermocouple to be burned out or open.

Jim, as I mentioned before they do average. If you connected say
flashlight batteries of slightly different voltages in parallel
then quite high currents would flow because their internal
resistance is low but thermocouples have comparatively high
resistance therefore limiting the current that will flow.

Picture a slightly high voltage TC in parallel with a slightly
lower voltage TC. The high one will "pull" the voltage up
slightly. Now add another of the same voltage as the high voltage
one. This one will "pull" the voltage just slightly higher again
now add a lower voltage one, the voltage will drop slightly, as
this one pulls it down. The current BETWEEN these TC won't be
very much because the resistance is comparatively high...see?

Remember that you're right about high current flowing IF the
supplies have different voltages AND are HARD supplies (they have
low internal resistance)

An example of a very hard supply is a 'regulated power supply',
you cannot 'pull' them at all, large currents will flow and fuses
will pop. They have very low internal resistance.
--

-Gord.