AC drives capable of operating at frequencies of 600 Hz or greater are generally referred to as “high-frequency” drives. These drives are considered by the U.S. and the EU to be dual-use devices, meaning that although they are commonly used in civilian applications, such as industrial equipment, they can also be used in military applications or in the creation and proliferation of weapons of mass destruction.

One of the most common industrial applications for high-frequency drives is in machine tools. For example, the spindle of a CNC tool often uses a drive running at 400 Hz or higher. However, these drives can also be used to build high-speed centrifuges, which are used in the enrichment of Uranium. In other words, high-frequency drives—those that operate at 600 Hz and above—can be used in the production of nuclear weapons. So it’s understandable that the U.S. and EU governments are very interested in tracking and controlling where they are sold and shipped to.

To this end, the export of high-frequency drives is controlled by U.S. dual-use regulation EAR Category 3, under ECCN 3A225. And in December 2014, the EU implemented amendments (Annex I) to its dual-use regulation 428/2009, addressing frequency converters (aka converters or inverters). The EU regulation controls the export of drives that have the following performance characteristics:

• multiphase output providing power of 40 W or greater;
• operating at a frequency of 600 Hz or higher; and
• frequency control better (less) than 0.2 %.

Similar regulations are also in force in China.

In order to export these devices to a location outside the country or jurisdiction of regulation, a business must obtain an export license from the government. A critical point of this regulation is that it applies not only to drive manufacturers, but also to OEMs and integrators who have incorporated these drives into a piece of equipment or a complete system. Failure to obtain the proper export license is a customs offense and can result in fines and potential prison sentences.

To avoid the export restrictions without affecting a significant population of legitimate industrial customers, several manufacturers have modified their high-frequency drives to operate at a maximum frequency slightly less than 600 Hz. Kollmorgen, for example, modified several of its drive products, limiting them to 599 Hz, and Control Techniques now limits some of its products to 550 Hz.