266 • Description
EAGLE 2 Operator’s Manual
Appendix O: EAGLE 2 Transformer Gas Tester Model
This EAGLE 2 Transformer Gas Tester Model is specially set up for electrical transformer
gas testing. Large electrical transformers are filled with oil which surrounds the
transformer coils, and they have an inert gas head space above the oil. When a transformer
begins to fail, electrical arcing between the conductors of the coils can cause flammable
gases to form in the head space. By testing the head space for these gases, and recording
trends of the readings, an early warning of transformer failure can be determined, and the
transformer can be removed from service before it explodes.
Description
The standard setup and calibration for the catalytic combustible channel on a Transformer
Gas Tester Model setup is for hydrogen with a range of 0 - 5.00% volume. When set up
this way, the catalytic sensor will not respond to or will respond only slightly to the
presence of methane.
Since the head space being tested is filled with nitrogen, there is no oxygen in the test
sample. The catalytic sensor requires oxygen in order to operate, so the instrument is
supplied with a snap-on dilution fitting with a dilution ratio of 1:1 (one part air to one part
sample). This fitting blends the sample with ambient air before entering the instrument,
which provides sufficient oxygen for the sensor to work.
The instrument is also supplied with a sample bag.
Operation
1. Turn the instrument on and allow it to warm up.
2. Attach the dilution fitting directly to the front of the instrument. Attach the probe to
the dilution fitting.
3. Press the AIR
▲
YES button in fresh air to zero the instrument.
4. Connect the deflated sample bag to the sample valve on the transformer and open the
valve slightly to fill the sample bag. Close off the sample bag and remove it from the
transformer valve.
5. Attach the sample bag to the probe and open the sample bag.
The sample will now be drawn into the instrument. After about 45 seconds note and
record the display reading. Compare this reading to historical data to determine the
condition of the transformer.
NOTE:
The EAGLE 2 can be calibrated either with or without the dilution fitting in
place. If calibrated without the dilution fitting in place, then display readings
must be doubled to determine the actual gas concentration. If calibrated with
the dilution fitting in place, then the sample bag must be used during
calibration, and the display readings will be the actual gas concentrations.
CAUTION:
If the dilution fitting is in place for calibration, do not use a demand flow
regulator. Use a sample bag. The use of a demand flow regulator with a
dilution fitting when calibrating will result in an inaccurate calibration.
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