The Brazilian motor-maker WEG has developed a range of “super premium efficiency” motors which, it claims, offer the highest efficiencies on the market, exceeding the requirements of the impending IE4 classification across their entire output range.

The WQuattro motors (above) are hybrid machines that combine conventional three-phase distributed windings and rotors with an aluminium squirrel cage and internal high-energy, rare-earth (NdFeB) magnets. According to WEG, this design makes them ideal for direct-on-line starting and for accelerating up to synchronous speed. In such applications, the motor speed will not vary with load – even if there are overload variations or voltage drops – as long as the mains frequency remains constant.

If the motor speed needs to be varied, the WQuattro motors can be used with V/f or vector inverters, offering an extended speed range with constant torque. Inverter control also allows several motors to operate in synchronism, fed by the same inverter. When used with inverters, the motors do not need positioning or speed sensors.

The motors’ synchronous operation results in low bearing temperatures, ensure long operating lives with low maintenance. They do not need overload protection relays.

The WQuattro motors are aimed mainly at users who consider energy saving a priority. The motors have no energy (joule) losses from their rotors, resulting in low ownership costs, low CO₂ emissions, and rapid returns on investment, according to WEG. The graph (above) shows how four-pole, 50Hz, versions of the motors exceed the IEC IE4 efficiency rating in all frame sizes.

The motors have the same frame size as standard induction motors with a similar output, making them easy to retrofit into existing applications.

The WQuattro motors are available in four- and six-pole versions, in frame sizes from 80–132S, with outputs from 0.37–7.5kW. They have class F insulation and are suitable for operation on 230/400V, 400/690V or 525V supplies.