The Expanding Role of Variable Frequency Drives in Naval Automation

Variable Frequency Drives (VFDs) have provided improvements in the U.S. Navy across a myriad of shipboard applications through replacement of full voltage across-the-line contactors and modification of earlier hydraulic designs.  The Collective Protective System (CPS) and Electronic-Standard Tensioned Replenishment Alongside Method (ESTREAM) are two examples.  These applications offer a revealing list of long term benefits of maintenance savings, equipment performance gains, and overall operational efficiencies.  In the case of the CPS, innovatively the engineers applied the power affinity laws and electrical power triangle principle to gain savings on the system’s power consumption and alleviate motor wear and tear.  For the ESTREAM, the VFD’s torque limit feedback was applied to achieve more responsive tension and speed control of the underway replenishment (UNREP) process.  Because extended equipment service life, increased reliability, and greater performance directly translate to a greater ability for the ship to accomplish its mission, such compelling reasons will generate further adoption of VFDs into other applications of the modern navies of today.