The lightning surge induced onto the extension wires
propagates not only to the thermocouple transmitter but also to the
thermocouple. To protect the thermocouple, another Model MDP-TC Lightning
Arrester for Thermocouples should be installed closely to it, as shown
in the figure. The temperature at the location of the lightning arrester
must not change suddenly but be stable, or a measurement error will
increase.
When we install a lightning arrester onto the extension wires, we
insert metals that are different from the thermocouple and the extension
wires. If the temperature at their connections is not the same, an
error emf is generated. The longer the extension wires outside a building,
the higher the possibility of lightning damage.
When the length of the extension wires becomes longer than 30 meters
(100 ft) outside the building, you should start investigating the
need of lightning arresters. |
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| M-System has flexible solutions to meet your specific
application and requirements. Consult our Signal Conditioners Data
Library. |
|
How
can we protect a thermocouple from lightning?
In
a case of a long transmission distance between the thermocouple and the
thermocouple transmitter, a lightning surge may enter the extension wires
and destroy the transmitter. We recommend installing M-System Model MDP-TC
Lightning Arrester for Thermocouples onto the extension wires, close to
the transmitter.