Groth, it's pretty cool, I can frequency modulate that waveform by positioning the hoses. A "twisted pair" arrangement gives a quite high frequency...
I think I'll just ground the radiator.
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Originally Posted by unregistered
re the pump(s)
yes, there is a cyclical pressure, and flow, variation
but the tc of your wb is greatly larger
use a moving average
like your sensitivity, but the value seems low
want some Shin Etsu for a comparison ? (for which I 'know' the value)
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I have the log output as a .csv file so I can look at it with any kind of averaging.
Shin Etsu TIM data? very interested to see what others get.
As regards it being low, I can't comment. I think the method is sound (the linearity of the three series sensors is compelling) but I am willing to be convinced otherwise. It is always a little uncertain when inter/extra-polating.
I have just finished calibrating the water sensors after making them properly rather than being taped to a barb with foam tape.
I am also checking the correlation between electrical power, fluxblock power and power to water. The power based on voltage (which I am logging) and resistance (which is nominally 2ohms) , W=V^2/R , compares rather well with the fluxblock calculation (W=k*A*DT/L). At the moment I can not log current (missing a 0.01ohm shunt) so I am not certain of the electrical power number, the heater resistor has a tolerance of 1% and a T coeff of -0.002 - +0.008%/°C, so this can vary a little bit.
Insulation at the moment is...
... crumpled toilet paper.
Works fairly well. I need something easy to remove, neoprene blocks probably.
Does anyone have any suggestions for an insulating plate to go under my heater. Something rigid and with a high compression strength but with good insulating properties. I cannot seem to find anything which is much better than the Lexan plate I am using, all the phenolic resins and such have a thermal conductivity of about 0.2 W/m.°C - the same as Lexan. ?