Dynamatic noticed that the controllers were operating at a higher level of current than the nameplate required, which accounted for the overheating. The excess current was evidence that there was a problem with the field windings in the eddy current drives. At this point, Dynamatic was asked to offer a comprehensive overhaul of the existing units, including the motors.
After interviewing Dynamatic and several VFD/Motor vendors, the City and Engineer concluded that Variable Frequency Drives, cost, space considerations and cooling requirements were not favorable for the project. Their best option was to replace the Eddy Current Drives in kind with new Dynamatic SPMV-8260 units, they are rated at 1250hp, 514 rpm, 4160 volts. The most influential factor for the replacement, was the expected life span of the products. They received one report from a VFD vendor, to expect the life span of a VFD to be about 7 years. Dynamatic drives and digital controls have been proven to outlast VFDs by as much as 6:1, dramatically reduce the pump stations lifetime operating costs.