Quad Plus designed a custom configuration of standard products to meet the end user’s requirements for power density, mechanical stability, and transportability.
To save space and reduce the overall part count, Quad Plus engineers chose the Rockwell PowerFlex 755TM modular aircooled inverter system as the basis for two 4000 ADC common bus lineups serving nine 600 HP motors at 600/690 VAC per lineup. Each lineup includes reactor filtration, rectification, and a system of brake choppers to mitigate excessive regenerative energy over the needs of adjacent inverter systems.
A unique feature of the design provides a tie circuit to connect the two 4000 ADC busses, which allows the available energy and braking resources of each lineup to be shared by all eighteen motors. To simplify spares, inverter modules were limited to two common configurations and used in parallel to supply appropriate capacity.
For the 4000 ADC bus lineups, each motor operates from identical paired inverters. Two additional but separate lineups support their 2400 HP prime mover using five identical inverters in parallel on their own common DC bus. All lineup components were installed in custom enclosures to minimize the footprint and provide maximum mechanical integrity to withstand transport from site to site.