Can someone tell me how the EGT are measured?

Question

Can someone tell me how the EGT are measured?

Answer 1

Typically by a thermocouple or "probe" installed in the exhaust stream from one or more cylinders.

Answer 2

well, I have seen my cheats so again i will use them to fortify my answer.

First the metals used are bi-metal meaning as John B says dissimilar metal which may I add Bit Pilsman says alumel & chrommel is again very right.

there are 8-10 probes and the important thing is they are measured by averaging the 10 temp. value read-out so as to have a true temp. Usually on the gage there is a yellow band meaning caution on these temp read-out and a red band where in the master caution light will illum. and a red light+warning bell. Pilots note this hight egt read-out and the time it stayed on that temp. for a B737 CFM56-B1, on T/Off an excess of  90 sec on 930 deg.C temp. a boroscope must be done on the engine is recommended.

Now I have to lock on my answer.

Answer 3

Close deepset, its chrome /alumel on a twisted wire feed mostly K type, Normally come with a fixed length of harness which must NOT be cut as it alters the circuit charateristics.

In multi-can GT's, one sensor for each can which can be read independently or averaged across the whole set.

No electrical supply is required on the majority of small systems as gauges are direct reading from probe output.

Answer 4

The EGT instrument uses one or more probes mounted in holes drilled through the exhaust pipes at strategic locations.  

If it is a simple EGT gauge that gives one temperature reading for the whole engine, the probe is mounted as close as possible to the place where all the exhaust lines come together to form the exhaust manifold.

If it is an engine analyzer, there is a separate probe in the exhaust pipe for each cylinder.

Answer 5

Yep, and they use alumel and chromel twisted pair wire to run from the thermocouple to the indicator.

Answer 6

Thermocouple similar to the one on your gas water heater to sense when the pilot light goes out. A thermocouple uses dissimilar metals to create a voltage. The higher the temp the higher the volts. In your water heater that voltage trips the gas shut off valve closed. In an airplane the volts are read on voltmeter only instead of volts they mark the guage in degrees celsius and call it EGT. Tricky huh. But it works.