Compact sensorless ac drive for permanent magnet motor applications
30 November 2009
Parker Hannifin has introduced a family of ac drives that allows energy-efficient permanent magnet motors to be used in a wide range of pump, fan and compressor applications. The new AC650S Series avoid having to run permanent magnet motors with closed loop speed sensors, enabling them to be used as replacements for induction motors.
Using the AC650S Drives to switch from induction to permanent magnet motors can cut energy consumption by up to 12% while reducing the combined drive and motor envelope by as much as 75%.
To date, permanent magnet motors have not been widely used in many industrial applications as they require additional speed or position sensing mechanisms and control by high end drive units, making them relatively costly and complicated to install. As a result, even though they are less efficient and considerably larger in size, induction motors have generally been the preferred choice for design and production engineers.
By using an algorithm control, based on motor voltage and current output, the new AC650S Drive enables standard permanent magnet motors to be used in closed loop applications, without the need for additional sensors. Users thus benefit from the energy savings that can be achieved from brushless motors, with savings of up to 12% possible for a 0.75kW system. Permanent magnet motor drive applications can be as little as 25% the size of a conventional induction motor assembly.
The new AC650S Drives provide high start-up torque, without the need for additional tuning, and offer a range of features to make them quick and simple to setup and install. For example, each drive is supplied with free software configuration tools, with pre-set macros for many common applications, and requires just a few motor parameters to be input during commissioning.
Additionally, the AC650S has front panel mounted LCD and input controls, with simple diagnostics, integrated EMC filters and analogue and digital I/O, including RS232 programming ports. The new drive can also be supplied with optional Profibus-DP and Modbus RTU interfaces, while a cloning module is available to enable up to ten drive configurations to be stored for ease of maintenance.
The AC650S family of drives is available in three frame sizes, covering single and three phase applications, from .25kW to 7.5kW and output frequencies from 0 to 500Hz. Parker also provides full technical and applications support through its global network of manufacturing and customer service centres.
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