ROCKWELL Automation has released the Allen-Bradley PowerFlex 7000 medium voltage drive system. It permits direct connection of the MV drive to utility power without an isolation transformer.
It is designed for applications ranging in size from 150kW to 6200kW, the PowerFlex 7000 medium voltage ac drive has direct-to-drive technology, eliminating the need for isolation transformers on applications with either new or existing motors.
It has symmetrical gate commutated thyristors with a high voltage rating and the ability to be connected in series. This allows the PowerFlex 7000 to be rated up to 6600V without added complexity, reducing total component count and increasing reliability.
An active front end (AFE) rectifier uses active switching and selective harmonic elimination to reduce harmonics. The system has common-mode voltage protection, designed to mitigate common-mode voltage stress generated by variable frequency drives without using an isolation transformer.
By removing the transformer on an MV drive, the PowerFlex 7000 improves the efficiency of the entire installation. Transformer heat losses are eliminated and the increased air conditioning capacity often required for transformer cooling is no longer required. The drive system is more space and weight-efficient, with the entire drive system size reduced by up to 50% and weight by 70%.