When Mixing Solutions Limited, a supplier of industrial mixers for world markets, needed a test system that would enable it to accurately determine the current consumption and other electrical characteristics of its products, two ac variable speed drives from Vacon provided a versatile, convenient and cost-effective answer
At its production site in Newbury, Mixing Solutions, which is a member of the international PSML family of companies, manufactures a wide range of high-performance industrial mixing machines for applications in the petrochemical, chemical, water treatment and other sectors, a large proportion of the machines being destined for export.
The company carries out extensive testing on all of its products prior to despatch, and in 2010 it decided that it would be useful to include in this testing measurement of the electrical characteristics of the machines using exactly the same supply system as the site where the machine will ultimately be used.
Since supply systems vary considerably around the world, this requirement presented a challenge – how to replicate those supply systems cost effectively for a wide range of motor sizes with a test rig that could be powered conveniently from the standard 415V 50Hz UK mains supply.
For assistance, Mixing Solutions contacted T A Boxall & Co Ltd. After carefully analysing the requirements of the application, they proposed an approach based on the use of Vacon NXS-series ac variable speed drives.
For this project, a key feature of these versatile drives is the availability of the Multimotor 7add software option, which allows up to eight types of motor to be controlled from a single drive. When this option is used, the drive stores operating parameter sets that include, for example, full load current and power factor, for all eight of the motors, and these parameter sets can be instantly recalled as required by using the drive’s auxiliary digital inputs
To meet Mixing Solutions’ full range of testing needs, T A Boxall & Co Ltd produced a control panel for the project that incorporates two NXS drives, one rated 18.5kW, the other 75kW. This arrangement means that mixers with motor ratings from 2.2kW up to 75kW can be tested quickly and conveniently. The operation of the drive system is matched to the motor under test simply by using a switch on the panel to select the motor type.
A wider range of frequencies and voltages
A spokesman says: “The Vacon drives in our new testing panel have made it easy and convenient for us to check the electrical characteristics of our mixers before despatch. With the drives, we can accurately simulate 50Hz and 60Hz three-phase supplies over the voltage range 380V to 500V. This covers the supply systems for all of the markets we operate in but the drives could easily provide a much wider range of frequencies and voltages.”
When the new testing system was first installed at Mixing Solutions, the company envisaged that it would only be used to evaluate new designs and to test mixers destined for especially demanding or unusual applications. The system has, however, been found to be so convenient and easy to operate that it is now used to verify the performance of all mixers produced at the site.
For more information about ac variable speed drives from Vacon, please visit www.vacon.com.