If the technician believes that a hermetic compressor has a permanently open internal overload protector, when should the technician test the compressor?

Testing a hermetic compressor when it is cool is ideal because this state allows for the evaluation of the compressor's internal components without the influence of additional heat that may affect its operation. A cool compressor will not be in a state of thermal expansion as seen when the unit is running, making it easier to measure electrical resistance and conductivity without confounding factors that may indicate a functioning or compromised compressor.

In this scenario, if the internal overload protector is believed to be permanently open, cooling the compressor stabilizes it at a baseline temperature. This provides a clearer indication of whether the compressor can energize and operate correctly under normal conditions, without the pressure and heat that occur during operation.

Testing a compressor while it is bypassed or while it is running would introduce other complications that could confuse the results of the test. Running conditions can lead to erroneous readings due to fluctuating pressures and temperatures, while a bypassed compressor may not represent normal operational conditions, leading to misleading conclusions about its functionality.