Thermocouple Extension
03-19-2010, 07:22 PM
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Thermocouple Extension
Hello everyone,
I want to extend the length of the thermocouple on my turbine by 36 inches. I bought a heavy duty JR 36 inch servo extension. I this okay to use?
Chris
I want to extend the length of the thermocouple on my turbine by 36 inches. I bought a heavy duty JR 36 inch servo extension. I this okay to use?
Chris
03-19-2010, 08:41 PM
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RE: Thermocouple Extension
Hello.
Maybe I am wrong, but the thermocouple that came with my ECU set has a different type of wires. Its like some type
of steel wires or something. I tried to extend the length like yourself, but the conventional lead solder didn't work. I have
to use silver solder and brazing flux to get the copper wires to stick to the thermocouple wires.
Maybe I am wrong, but the thermocouple that came with my ECU set has a different type of wires. Its like some type
of steel wires or something. I tried to extend the length like yourself, but the conventional lead solder didn't work. I have
to use silver solder and brazing flux to get the copper wires to stick to the thermocouple wires.
03-19-2010, 09:22 PM
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RE: Thermocouple Extension
It is highly possible that you have an Omega thermocouple on your engine.
What turbine type are you using?
Most thermocouples are pretty low tech devices, and use different alloys to create voltage when exposed to heat. "K" type are very common in our hobby, and use Alumel and Chromel.
Thermocouople wires are very special alloys, and are calibrated for each type of thermocouple. You cannot expect to use a JR extension harness with any degree of accuracy.
The thermocouples used on our engines can be equipped with extender wires. Omega instrument is a very large manufacturer of thermocouples, and offer retractable extension wire harnesses.
See www.omega.com
Example: Part Number TECK10-2 priced at $15.00 in 1 and 4 foot lengths. (A 1 foot length will expand to 5 feet long).
The connector style determines part of the part number...see the webpage for more info so you can order the correct type.
If you know or can determine your thermocoouple type, their data sheets will list the correct extender.
If your connector is yellow, you have a "K" type, based on ANSI MC96.1 color coding.
What color is the connector??
What turbine type are you using?
Most thermocouples are pretty low tech devices, and use different alloys to create voltage when exposed to heat. "K" type are very common in our hobby, and use Alumel and Chromel.
Thermocouople wires are very special alloys, and are calibrated for each type of thermocouple. You cannot expect to use a JR extension harness with any degree of accuracy.
The thermocouples used on our engines can be equipped with extender wires. Omega instrument is a very large manufacturer of thermocouples, and offer retractable extension wire harnesses.
See www.omega.com
Example: Part Number TECK10-2 priced at $15.00 in 1 and 4 foot lengths. (A 1 foot length will expand to 5 feet long).
The connector style determines part of the part number...see the webpage for more info so you can order the correct type.
If you know or can determine your thermocoouple type, their data sheets will list the correct extender.
If your connector is yellow, you have a "K" type, based on ANSI MC96.1 color coding.
What color is the connector??
03-19-2010, 10:30 PM
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RE: Thermocouple Extension
On my Rhino I believe I was told by Eric that I could use a JR servo extention to extend the EGT sensor to the ECU. Worked for the Rhino , runs fine .I had extended it over 24" maybe up to 32"
03-19-2010, 10:51 PM
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RE: Thermocouple Extension
THe Jet Central engines have a "K" type thermocouple, but have terminated it in a JR type connector for ease of manufacturing.
The ECU is evidently calibrated to allow a JR extension, which differs in resistance from the normal thermocouple wiring. Resistance changes in the thermocouple wiring changes the voltage output, which affects the reading.
The ECU is evidently calibrated to allow a JR extension, which differs in resistance from the normal thermocouple wiring. Resistance changes in the thermocouple wiring changes the voltage output, which affects the reading.
03-19-2010, 10:57 PM
#6
RE: Thermocouple Extension
The manual for my Merlin 160 states you can use a servo extension and this will give you about a 10 deg error at max. temp.
Should be good to go as long as you can get a good connection with the extension. Use an extension with gold plated ends to keep the conductivity good.
PaulD
Should be good to go as long as you can get a good connection with the extension. Use an extension with gold plated ends to keep the conductivity good.
PaulD
03-20-2010, 10:22 AM
#8
RE: Thermocouple Extension
ORIGINAL: flyexperimental
On my Rhino I believe I was told by Eric that I could use a JR servo extention to extend the EGT sensor to the ECU. Worked for the Rhino , runs fine .I had extended it over 24'' maybe up to 32''
On my Rhino I believe I was told by Eric that I could use a JR servo extention to extend the EGT sensor to the ECU. Worked for the Rhino , runs fine .I had extended it over 24'' maybe up to 32''
03-20-2010, 05:41 PM
#9
RE: Thermocouple Extension
The voltage generated by a thermocouple is governed by the temperature difference between the hot and cold junctions. The cold junction is where the thermocouple wires (nickel-chrome and nickel-alumel for a K type) meet the copper conductors within the ecu.
By using copper wires (servo leads) to extend a thermocouple the cold junction is still where the nickel-chrome and nickel-alumel meets the copper ie some distance away from the ecu at the joint to the servo lead. The copper wire simply transmits the voltage present at the new cold junction to the ecu.
If the ecu and the servo lead joint are at the same temperature there should be no error however this isnt likely and the temperature difference would be the error.
By using copper wires (servo leads) to extend a thermocouple the cold junction is still where the nickel-chrome and nickel-alumel meets the copper ie some distance away from the ecu at the joint to the servo lead. The copper wire simply transmits the voltage present at the new cold junction to the ecu.
If the ecu and the servo lead joint are at the same temperature there should be no error however this isnt likely and the temperature difference would be the error.
