Measurement and control The output e.m.f. from a nicrosil-nisil thermocouple (ty
ID: 2080729 • Letter: M
Question
Measurement and control The output e.m.f. from a nicrosil-nisil thermocouple (type N), with its reference junction maintained at 0 degree C, it 4.21 mV. What is the measured temperature? A platinum 10% rhodium-platinum (type S) thermocouple is used to measure the temperature of a furnace. The output e.m.f., with the reference junction maintained at 50 degree C, is 5.975 mV. What is the temperature of the furnace? In a particular industrial situation, a nicrosil-nisil thermocouple with nicrosil-nisil extension wires is used to measure the temperature of a fluid In connecting up this measurement system, the instrumentation engineer responsible has inadvertently interchanged the extension wires from the thermocouple The ends of the extension wires are held at a reference temperature of 0 degree C and the output e.m.f. measured is 21.0inV. If the junction between the thermocouple and extension wires is at a temperature of 50 degree C. what temperature of fluid is indicated and what is the true fluid temperature? A chromel - constantan thermocouple measuring the temperature of a fluid is connected by mistake with copper-constantan extension leads (such that the two constantan wires are connected together and the copper extension wire is connected to the chrome I thermoompic wire). If the fluid temperature was actually 250 degree C, and the junction between the thermocouple and extension wires was at 80 degree C, what e.m.f. would be measured at the open ends of the extension wires if the reference junction is maintained at 0 degree C? What fluid temperature would he deduced from this (assuming that the connection mistake was not known about?Explanation / Answer
14.2] Answer is 147 degree celcius.
This is obtained from the nicrosil- nisil type N thermocuple chart of junction temperature and emf generated; when reference junction is maintained at 0 degree celcius temperature.
14.3] Answer is : 671 degree celcius(obtained from the table) +50 degree celcius (reference junction temperature) = 721 degree celcius.