This rugged, industrial quality DC-AC sine wave inverter was developed for operation on cranes and in similar heavy-duty applications that require high input overvoltage capability. The 250Vdc nominal input design is capable of operating reliably up to 600Vdc input without any damage. This inverter offers a significant advantage over other inverters with standard industrial input ranges, which typically fail under these operating conditions. Microprocessor-controlled high frequency PWM technology enables compact construction, low weight and high efficiency. The unit is constructed with internal modules, one FID2000 and three KHH2000 modules. The DC-DC input stage converts the input voltage to a DC bus voltage, which feeds two MSI1500 DC-AC modules to generate the required AC output. The input and output are filtered for low noise. The built-in fans provide sufficient airflow for operation without de- rating to the specified temperature. The fans can be equipped with filters to enable operation in dusty conditions. The fans draw air into the unit. Most heat generating components are installed on aluminum heatsink blocks which are thermally connected to the base plate. This also ensures exceptional mechanical ruggedness. Conformal coating provides protection against humidity and airborne contaminants. Full electronic protection, low component count, large design headroom, and the exclusive use of components with established reliability contribute to a high MTBF. It is manufactured at our plant under strict quality control.