More stainless-steel motor choices available

By Control Engineering Staff August 25, 2005

Rockwell’s MP-Series stainless-steel servo motors supply peak torque in the range of 11.1-67.8 Nm (98-600 lb-in.) and come in 100-, 130-, and 165-mm frame sizes.

Judging from recent product news releases, availability of motors and motor types with all stainless-steel construction is on the rise. Recent examples include a high-performance servo motor from Rockwell Automation , intended to meet hygienic design standards found in government-regulated industries, and Leeson Electric’s permanent magnet (PM) dc motors for duty in pharmaceutical, food and beverage processing, clean room, and severe chemical processing applications. This follows Baldor Electric’s earlier announcement of its all stainless-steel brushless servo motor line ( see Sept. 2004 Discrete Control Monthly E-Newsletter ).All these motors feature ability to withstand frequent washdown with high-pressure or caustic liquids.

Allen-Bradley MP-Series stainless-steel motors from Rockwell Automation meet IP66, IP67, and IP69K sealing standards. Their smooth cylindrical housing made of passivated 300-series stainless steel withstands 1,200-psi washdowns for water and solid ingress. It can be cleaned with caustic chemicals without worry about corrosion or other motor damage, and doesn’t trap contaminating materials. MP-Series motors also incorporate a shaft slinger to protect the shaft seal against direct high-pressure spray and abrasives. Because of stainless-steel construction, MP-Series motor can be applied on the machine close to where it’s needed. This reportedly eliminates housings and extra chains, gears, and bearings, along with saving space.

Also helping washdown protection and simplifying installation is MPS motors’ factory-sealed flying leads that eliminate the need to open the motor to make connections. These motors are part of Rockwell’s overall Kinetix Integrated Motion solution.

New from Leeson Electric are permanent magnet (PM) dc motors with all stainless-steel (SS) construction, said to be an “industry first” for this motor type. Part of its Premium All-Stainless Steel product line, these PM dc motors feature 300-series SS external components; no paint or coating on exterior surfaces; shaft seals on both ends of TEFC (totally enclosed, fan cooled) motors—shaft-end only for TENV (non-ventilated) motors—and end shields o-ring sealed to the frame.

Removable hydrophobic “breathers” in conduit box and at opposite shaft end bell equalize pressure to help prevent moisture entry into the motor. To further minimize moisture entry, holes for exterior fasteners are eliminated where possible. This includes a laser-attached nameplate that eliminates holes in the frame and trapping dirt/contaminants. Bearing lock screws are internal; and conduit-box mounting screws are eliminated.

Leeson Electric is a subsidiary of Regal-Beloit Corp.

—Frank J. Bartos, executive editor, Control Engineering,