The Vacon X4 and Vacon X5 variable-speed AC drives are officially certified by Underwriters Laboratories for outdoor use.
Performance, connectivity, size, longevity & total cost of ownership determine the best drive for your application
The best motor drive on the market is the one that best suits the application. Many factors need to be taken into account when determining which drive is the best fit. Performance, connectivity, size, longevity and total cost of ownership are only a few of the features that determine the best drive for your application.
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“The best motor drives on the market are all digital from interface to output,” says Dennis L. Morrow, vice president of marketing and sales, ORMEC Systems Corp.
“All digital drives replicate exactly; analog components can and will vary from drive to drive.”
Firmware upgrades for digital motor drives can be easily added, some times in the field, and data logging can be accomplished on current vs. past performance. With all digital drives, the user is also able to install special algorithms to customize performance.
Harsh Environments
In designing for harsh environments, drives can change in terms of functionality and performance in two approaches, according to Clark Hummel, manager of application engineering, Intelligent Motion Systems (IMS).
“The first approach is to enclose a standard product within an appropriate enclosure,” begins Hummel. “The second is to design the device to successfully operate when exposed to this environment. At IMS we chose the latter, designing much of our Mdrive product line to optionally conform to the IP65 specification.”
One of the most prevalent issues in providing a sealed unit is in thermal management. According to Hummel, forced air-cooling as is used in many motor drives is totally inappropriate when designing a sealed unit. Through judicious use of thermally conductive materials and thermal property design, proper thermal dissipation can work well in a sealed motor drive.
Michael Björkman, Vacon global segment director of mining and conveyors, doesn’t really see a change.
“The functionality and performance is a function of the control system, processor performance and main circuit design and performance,” says Björkman. “The degree of protection does not come into this picture; high-performance drives are required in all environmental protection classes.”
Driving Change
Drives have become smarter as they have evolved, many can auto-tune not simply the family of motors for which it was designed, but any motor.
For IMS’ Hummel, the most innovative way in which motor drives have changed is in the integration of motor, drive and programmable controller into one package.
“This integration greatly reduces wiring costs, panel space and engineering labor costs, while promoting ease of use and reducing downtime,” says Hummel.
“Drives have also benefited from real-time diagnostics, such as oscilloscopes with profile storage and recall for performance comparison history,” says ORMEC’s Morrow.
According to Vacon’s Björkman, the basic topology has not changed at all.
“The main changes are in the fields of useability and MMI – the increased processor power available for the same cost makes it possible to integrate more system control features into the drives (local PLCs), as well as to create drives tailored for a specific market, based on a common hardware platform,” says Björkman.
“Trends concerning environmental (physical and EMC) have also changed the materials used as well as some of the sizing details.”
Not Too Long Now
Motor drives will continue to see improvements in interoperability as they become more compact – even though some limits are set by the cable size required, as well as the need to be able to get your fingers into the connector space.
According to Hummel, “Connectivity will improve to allow greater bandwidth and improved message timing precision, which will then allow for greater synchronization between devices.”
“The communication capabilities will evolve,” adds Björkman. “Specialized drives will be developed for specific uses and the influence on the electrical and physical environment will continue to decline."
For Morrow, changes will come in the form of greater feature integration into the power modules and new integrated safety features. He also foresees higher switching frequencies and loop-updated frequencies with less audible noise and higher bandwidths. Also look for more local intelligence (less communication needed when used in multi-axis networks) and complete product documentation stored in the memory.