Answer / khurshid

third wire used in RTD for the compansation of lead wire
resistancce.

Answer / preeti

three wire connections can eliminate connection lead resistance effects from measurements

Answer / gomsy

third wire is used as lead wire compensation i.e it is
connected in parallel,hence effective resistence decreases
and will be helpful to calculate higher range of tempreture

Answer / santosh r apre

three wire connections can eliminate lead resistance from
mesurements.

Answer / sam.r

Most RTD’s incorporate a third wire with resistance R3.

This configuration provides one connection to one end and
two to the other end of the sensor. Connected to an
instrument designed to accept 3-wire input, compensation is
achieved for lead resistance and temperature change in lead
resistance. This is the most commonly used configuration.


If three identical type wires are used and their lengths are
equal, then R1 = R2 = R3. By measuring the resistance
through leads 1, 2 and the resistance element, a total
system resistance is measured (R1 + R2 + RE ). If the
resistance is also measured through leads 2 and 3 (R2 + R3),
we obtain the resistance of just the lead wires, and since
all lead wire resistances are equal, subtracting this value
(R2 + R3) from the total system resistance (R1 + R2 + RE)
leaves us with just RE, and an accurate temperature
measurement has been made.

Answer / md.afroz afroz

Third wire use in RTD for more accuracy

Answer / seshu

The connecting wires long,resistance of wire changes as ambient temp fluccuates.to eleminate this problem we use 3 wire rtd

Answer / yacine

the RTD is
installed some distance away from the transmitter. Since
the connecting
wires are long, resistance of the wires changes as ambient
temperature
fluctuates. The variations in wire resistance would
introduce an error in the
transmitter. To eliminate this problem, a three-wire RTD is
used

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