Energy efficiency of VSDs

This paper describes the performance tests for variable speed drive systems. Most of the applications for VSD systems involved in variable torque loads such as fans and centrifugal pumps, where the load power varies as the cube of the speed. The performance tests of VSD systems are planned to measure efficiency of the VSD unit and the efficiency of the involved motor. The real benefit of VSD systems is the reduction of energy used to provide the quantity of end product of the pumps or fans. The result of these tests were tabulated and consolidated in the paper. Each manufacturer received a copy of reports on their own motors.