Optimal flux limits motor temperature rise
WEG has found a way to limit motor temperature rise at low speeds by using what it calls Optimal Flux Technology
This relies on finding the magnetic flux that minimises motor losses at each speed while keeping torque constant and programming this into the frequency converter. This is achieved by reducing frequency (to reduce motor speed) and reducing voltage to keep the flux constant.
WEG’s theoretical modelling of the benefits of OFT has been confirmed by trials. R&D manager Sebastião Nau said: “A comprehensive performance trial was set up against four major competitors using 3kW, 4-pole 1800rpm motors, over a 1000:1 speed operating range. This clearly showed that WEG’s Optimal Flux Technology strategy for a WEG NEMA Premium Efficiency, NEMA High Efficiency and IEC Premium Efficiency EFF1 motors motor/CFW-09 drive combination ran significantly cooler than its competitors.” The technology is a feature of the company’s newly launched CFW11 frequency inverter series.
