Motion System Design

Variable frequency drives manage shear rates

Efficiently and reliably managing the shear rate of its high-speed, in-line mixers and high-shear colloid mixers is crucial to Bematek Systems Inc., Beverly, Mass.

David Ekstrom, president and general manager, says the company's flexible, modular engineered designs address the challenge of adding several ingredients to produce smooth, homogenous end-products for the food and beverage, cosmetic, pharmaceutical, biotechnology, and chemical markets. Bematek's in-line mixers can be precisely configured for an application, and reconfigured as future needs or ingredients change.

The drive is critical in setting a repetitive and constant shear rate for in-line mixers and colloid mills. That is why Bematek uses variable frequency drives from AC Technology, Uxbridge, Mass. “In most cases, our clients' operators control the speed via their frequency input, starting and stopping the unit right there, on the line,” Ekstrom said. In addition, he stresses the importance of the right footprint, explaining, “The drive package is small which helps keep our control box compact.” The drives also operate effectively in washdown applications.

The use of a colloid mill can increase product yield and enhance other product characteristics, such as color and texture. The right high-shear colloid mill increases processing parameter flexibility.

To ensure uniform performance throughout milling, Bematek uses AC Tech's MC Series (NEMA 1, 4/12, and 4X) and SCM Series. The drives offer user-friendly programmability for current limiting, which signals operators to overload conditions without shutting down.

For more information, visit AC Technology at or Bematek Systems at

Motion control distributors join together

Motion control distributor Minarik Corp., Glendale, Calif., purchased Southwest Controls Inc., Anaheim, Calif. Southwest Controls will be a wholly-owned subsidiary of Minarik, which will also acquire the company's Orange County and San Diego locations.

The companies will retain separate identities and trade names. Sales and customer support functions will be combined.

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