----- Original Nachricht ----
Von: Horace Heffner <[email protected]>
An: Vortex-L <[email protected]>
Datum: 12.10.2011 08:31
Betreff: [Vo]:T2 thermocouple anomalies
> The various anomalies associated with the T2 thermocouple, like its
> disconnect from the Pout, may be explained by the close distance, a
> few cm, of the internal fins to the lid. The T2 thermocouple rod,
> which protrudes down through a fitting in the lid, may be long enough
> to reach the fins.
>
> Dennis Cravens noted that RF affects thermocouples. They rectify the
> signal. This has been observed in CF experiments. This would mean
> the RF signal could bias T2 upwards during the heat after death period.
>
I have built and tested electronic thermoamplifiers myself professionally.
Metallic thermocouples (e.g. Ni-CrNi) have very low DC and AC impedance and
cannot rectify RF.
The problem are the amplifiers, and the zeropoint compensator these are /very/
sensitive and can rectify RF.
This however should not happen with measuring instruments that are certified.
Problems /can/ appear if the noninsulated tip or the wires are shorted by
another kind metal.
