Questions for you

Per IEC61373, long life test requires inputs of ASD .452 and .25, [is this g2/Hz?] trans. and long., respectively, in the range of 5-20Hz, and at 3.9 and 2.9 RMS [how arrived at these numbers?] acceleration for trans and long, respectively. The test lab or supplier has opted to test in both x and y at 3.9 m/s/s, rather than use the lower 2.9m/s/s. Since this is a long life test as opposed to a resonance sweep, I'd guess the higher acceleration level is better (more stringent). However, is there a down side to testing at a more severe acceleration for this long life test? [Nothing obvious. How much stroke does this require of your shaker?] The UUT is an inverter package with lots of power conversion components mounted within the enclosure. [Where is it located in service? Are your numbers based upon in-service measurements?] Also, the resonance is defined as a doubling of the input vs output displacement amplitude, or a doubling of the g-level amplitude? [What has this to do with the earlier sentences?]