Microprocessor-controlled, high-frequency pulse-width-modulation (PWM) technology drives the PSI 300 series of dc-ac inverters, enabling 300-VA pure sine-wave output voltage. Full encapsulation with a thermally conductive, military-grade silicon rubber compound ensures immunity to high shock and vibration levels, as well moisture and airborne contaminants, says developer Absopulse. The inverters provide a stable sine-wave output of 115 V ac continuous at 60 or 400 Hz, or 230 V ac continuous at 50 Hz. They’re rated for continuous operation at +70°C when installed on an appropriately sized heat-sinking surface. Operation is from a 24-, 48-, 110-, or 125-V dc line voltage. Output regulation is ±2% combined across all input line and load condition. Input and output are filtered for low noise. The input meets EN55022 Class A conducted and radiated requirements with wide margins. Options include an output-fail alarm (Form C) and remote shutdown or enable. The PSI 300 inverters suit the powering of sensitive electronic loads in mining, transportation, oil rigs, and other severe environments.