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Textile manufacturer Buettner has reduced power consumption by 33 per cent and increased machine utilisation by 80 per cent, simply by fitting WMagnet motors on its ring spinning machines.

Buettner, from Brazil, produces more than two-million bath towels each month for export to around 40 countries.

The company bought three WMagnet motors from WEG to assess their performance on its ring spinning machines.

Their success means Buettner will fit WMagnet motors as standard on all 45 of its ring spinning machines.

The ring spinning machines transform raw cotton into threads of the desired thickness for each product, before being wound onto spools.

Previously the machines operated with standard induction motors at two discrete speeds; this meant it was necessary to stop the machine for each gear change – a process that resulted in substantial losses in production time.

Seeking to overcome this problem, WMagnet motors were installed; these are controlled by WEG frequency inverters that vary the machine revolutions from 0rpm to 1,800rpm.

‘This arrangement means that our personnel no longer need to stop the machine to change gears.

‘We also benefit from the soft start provided by the WEG VFD, which reduces machine wear,’ said Aires Fantoni, electrical maintenance supervisor at Buettner.

In addition to lower maintenance costs (practically zero), the variation of motor speed with constant torque and energy savings increases both the reliability and the performance of Buettner’s production line.

Marek Lukaszczyk, European marketing manager for WEG, said: ‘As demonstrated by the Buettner application, the WMagnet motors are ideal for applications where eliminating a gearbox is essential; the motors can do this because they can operate self-ventilated over a wide speed range.

‘The space saved by gearbox removal is complemented by the size of the WMagnet motor itself.

‘Compared with an equivalent induction motor, the volume of the PM motor is reduced by roughly 47 per cent, resulting in a higher torque/volume ratio and a reduced weight by as much as 36 per cent.

‘Moreover, the PM motor is at least one frame-size smaller than the induction motor and in some cases it can be two frame-sizes lower.

‘Reducing the frame size, the cooling system is consequently reduced for the same torque/power ratio, resulting in a significant reduction in noise.

‘Finally, as regards energy efficiency, the high energy magnets in our WMagnet motors have lower Joule losses in the rotor, compared with conventional squirrel-cage induction motors.

‘As Joule losses account for a significant portion of the total losses in induction motors, replacing the squirrel-cage construction with magnets ensures far greater efficiency – easily exceeding the requirements of new harmonised IE (International Efficiency) grading standards IE2 and IE3, which will soon replace the current voluntary EFF labelling scheme (EN 60034-2:1996),’ Lukaszczyk finished.

WEG Electric Motors

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