Chapter 3 – Operation
TestEquity TEC1 Thermoelectric Temperature Chamber
Page 3-3
Performance Considerations
The performance of all chambers is significantly affected by the characteristics of your test
sample. Factors include size, weight, material, shape, and power dissipation if energized.
The test sample should be placed in the chamber in a manner that allows for air circulation.
Multiple test samples should be distributed throughout the chamber to ensure even airflow and
minimize temperature gradients. Verify that the temperature gradients are within acceptable
limits, by measuring the chamber temperature at strategic points using a multipoint thermocouple
meter or data logger.
You may find that the temperature is different from what the temperature controller indicates at a
particular temperature. The correct way to adjust what the temperature controller “displays”
compared to what is measured at some point other than the controller’s sensor is with the
“Calibration Offset” parameter. See page 56 of the “EZ-Zone PM User’s Manual” for details.
Internal Test Fixtures
Some applications require internal fixtures to support test samples and provide a convenient
method of connecting wires and sensors. Fixtures must be designed to minimize their impact on
chamber functionality and performance.
Fixtures should be designed for easy removal to permit maintenance and cleaning of the
chamber. Fixtures should be constructed of stainless steel. This also applies to all screws and
fasteners. All welds should be passivated. To prevent rust and corrosion, never use iron or mild
steel even if it is painted or plated. Aluminum may be used. However, since the specific heat of
aluminum is double that of steel, it represents a greater load and will have more impact on the
chamber performance.
Make sure that all connectors, wiring, pc boards, and auxiliary components can withstand the
temperature extremes that they will be subjected to. In some cases, these components may not be
able to last after repeated tests and should be considered expendable.
