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Hybrid motor and drive designs set new benchmarks for efficiency

WEG Electric Motors (UK) Ltdvisit website

 

In its latest LV and MV motor and drive designs WEG is exceeding the requirements of the IEC 60034-30:2009 standard, a harmonised IE (International Efficiency) grading standard central to the EU’s new eco-design directive 2005/32/EC.

Electric motors are the single biggest consumer of electricity worldwide. They account for about two-thirds of industrial power consumption and about 45 per cent of global power consumption, according to a new analysis by the International Energy Agency.

Unsurprisingly, in view of these figures, electric motors have been one of the main target areas for improving energy efficiency. The resulting efforts in this area have generated new energy efficient standards, such as the latest IEC 60034-30:2009, a harmonised IE (International Efficiency) grading standard, which is central to the EU’s new eco-design directive 2005/32/EC.

WEG’s new WQuattro line of super premium efficiency motors employ a hybrid design claimed to achieve the highest efficiency in the market, exceeding the requirements of the impending IE4 Super Premium Efficiency classification across their entire output range.

For users who consider energy saving a major priority, the WQuattro line has been developed. It is an environmentally friendly range of motors that, due to its highly efficient performance – with no energy (joule) losses from its rotor – demands less energy from the grid. For the user, this translates into lower total cost of ownership, a reduction in CO2 emissions, and a faster return on investment.

A hybrid motor, the WQuattro integrates a conventional three-phase distributed winding, and a rotor with an aluminium cage and internal high energy magnets. This combination makes the WQuattro suitable for direct-on-line starting and acceleration up to synchronous speed. With this type of operation the motor speed does not vary with load, despite overload variations, or cases of voltage drop, as long as the mains frequency is kept constant. Moreover, there is no requirement for positioning/speed sensors, or special protection relays, and the low bearing temperatures that result from synchronous operation also ensure longer life and reduced maintenance for the motors.

In addition to developing highly energy efficient motors for general industrial and process applications, WEG is also focussing its design efforts on improving the efficiency of more specialist designs, such as permanent magnet (PM) motors. This technology has tended to be very much on the back burner, due to the design of standard squirrel cage motors, which are relatively inexpensive, robust and reliable, and well proven in operation.

PM motors deliver energy efficiency

WEG’s new WMagnet series of PM motors changes this situation by offering a range of user benefits that bring PM motors into mainstream usage. The WMagnet series delivers higher efficiencies – up to 97.5 per cent – compared with equivalent size induction motors, and reduces size by up to 50 per cent and weight by up to 36 per cent. In addition, the motors are, generally, at least one frame size or core length smaller than the equivalent induction motor, and in some cases can be two frame sizes smaller.

The energy efficiency of WEG’s PM design has been demonstrated in one of the prototype applications for the motors, at a textile mill. By replacing standard induction motors used on ring spinning machines with permanent WMagnet motors, the textile plant has reduced its annual power consumption by 33 per cent and increased its machine utilisation by 80 per cent.

Both the WQuattro and WMagnet are low-voltage motors; however, a substantial section of the motor market is MV, and here, too, the potential for energy efficiency is considerable. WEG is exploiting this potential with its new MV drive, the MVW-01, which achieves 99 per cent efficiency with a design that employs Multi-level Topology to minimise component levels, and high voltage (6.5kV) IBGTs to reduce motor harmonic currents to very low levels.

Unlike many MV drives on the market, which have 3 or 5-layer control, the WEG MVW-01 range has just two layers. The benefit of this is a reduction in the number of components in the drive, and commensurate improvements in efficiency and reliability. With energy costs at record levels, the efficiency performance of the MVW-01 drives is important. It has been calculated that for every 1 per cent of efficiency lost on 1MW drives, the user will pay an extra £5k per year on running costs – and that figure is just for the drive alone.

To find out more about WEG’s premium efficiency motors, visit the website at www.weg.net.

20 March 2012

WEG Electric Motors (UK) Ltdvisit website
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