HALT Testing of ConnectDER Solar Meter Socket Adapter
Crystal Instruments HALT Testing Lab is equipped with two Qualmark chambers (OVS 3.0 Typhoon HALT and OVS 2.5 HALT) and provides highly experienced HALT testing services.
The intent of the HALT process is to subject the product to stimuli well beyond the expected field environments to determine its operating and destruct limits. Failures that typically appear in the field from long periods of usage with lower stress levels are quickly discovered during the application of high stress conditions in shorter durations.
HALT is primarily a margin discovery process. To ruggedize the product, the root cause of each failure needs to be determined and corrected until its fundamental limit of technology is reached. This process will yield the widest possible margin between product capabilities and the environment in which it will operate, thus increasing the product’s reliability, reducing the number of field returns, and realizing long-term savings.
Many products are suitable for HALT testing, especially products requiring qualification to survive the elements. One example is the ConnectDER Solar Meter Socket Adapter, which is a UL listed and NEC compliant device that allows quick and cost-effective interconnection of solar PV systems to a home. The MSA is installed between the residential meter socket and utility meter, avoiding complex and expensive modifications to the main electrical panel
Figure 1: Photos of the DUT during the HALT test. Specific affixed sensors include a control accelerometer and a RTD temperature thermocouple.
Thermal Step Stress and Rapid thermal cycles are just two portions of the overall HALT testing process. Thermal characteristics and limitations must be considered. Components such as electrolytic capacitors, piezo electronics, or integrated circuits will cause system failure based upon their operational limits before the system as a whole may cease function. Discrete thermocouple placement can shed light upon anomalies.
Thermal Step Stress identifies the Upper and lower Operational or Destruct limits of the device.
Rapid Thermal Cycling utilizes the operational limits identified in Step Stress. These extremes are cycled from +/- extreme, typically for 5 cycles at an average excursion rate of 60°C/min.
Figure 2: Rapid Thermal Cycles Graph for the HALT Test
Combined Environment is the final stage of the HALT Experiment. This segment combines Rapid Thermal Cycling while increasing vibration incrementally. Leveraging upon accumulated stress, the synergetic means of excitation upon a fatigued device can further identify latent anomalies.
The typical formula for Combined Environment Vibration:
Vibration Operational Limit/Total number of Cycles = Increments per Cycle i.e. VOL of 50 gRMS for 5 cycles = 10 gRMS per cycle
Figure 3: Combined Environmental Graph for the HALT Test. This test went from 5 gRMS to 60 gRMS.
After completion of the HALT test, the ConnectDER Solar Meter Socket Adapter proved to be fully functional with minimal external wear.
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Table 1: Test Results
Crystal Instruments Testing Labs provides a wide range of testing services for products ranging from consumer electronics to ventilators, satellite components, and defense systems. This spectrum of industries illustrates how HALT can be applicable for most if not all devices - from consumable to mission critical. Recalls and sustainable engineering are costly, both financially and in consumer confidence.
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