Rare-earth magnets boost motor efficiency

Permanent magnet synchronous motor couples with a specially developed variable speed drive frequency inverter to provide efficiency levels better than Eff1.

WEG offers its WMagnet permanent magnet synchronous motor coupled with a specially developed CWF-09 variable speed drive frequency inverter to provide high energy savings with efficiency levels better than Eff1.

According to Siegfried Kreutzfeld, Technical Director of WEG Motors: "With outputs from 15 to 150kW, the cost competitive WMagnet offers efficiencies of around 95 to 97%, high constant torque over a wide speed range, low noise and vibration from a motor up to nearly 50% smaller and 36% lighter than the equivalent induction motor".

A constant torque with the motor running speed controllable over a 10:1 turndown ratio (up to 3000rev/min depending on model) means the WMagnet motor range is ideal for a wide number of applications, including elevators, conveyors, pumps, ventilation and compressors.

The high reliability and long working life of the WMagnet motor is ensured by its low temperature rise due to the reduction in electrical losses from the use of rare earth permanent magnets in the rotor.

Low maintenance costs are aided by the cool running which can prolong the bearing lubrication interval.

The WEG-developed WISE insulation system also provides extended life and reliability through enhanced specifications of all insulation materials.

The compact size of the WMagnet motors (between one and two frame sizes smaller than the equivalent power/torque ratio standard squirrel cage induction motor) derives from the low temperature rise feature, and the fan cooling system is therefore reduced in size.

Kreutzfeld adds: "Significant noise reduction to under 73dB(A), -3dB(A) better than standard induction motors, means the WMagnet is ideal in applications within buildings or other sensitive areas; a forced ventilation kit is not required even for heavy loads".

For precision control and optimum energy efficiency with the WMagnet motor, the specially configured CFW-09 drive uses WEG's unique vector control technology algorithm.

This enables control without the use of an encoder or position sensor and, by reducing the number of components, helps improve reliability.

As a synchronous motor, the WMagnet cannot be started directly from the power supply because accurate synchronisation of the supply waveforms with the rotor position is continuously required.

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