Press Release Summary:
Stearns 321 Series consists of 6 totally-enclosed, non-ventilated, armature-actuated electric disc brakes. They are available with static torque ratings of 3, 5, 7, 15, 35 and 50 lb-in. Brakes are designed for service in dirty or contaminated environments to decelerate or hold inertial loads when voltage to brake coil is disconnected. They are available in versions that will operate on 12, 24, 48, 90 and 180 VDC as well as 230 VAC.
Original Press Release:
Stearns(R) Introduces New 321 Series TENV Brake
MILWAUKEE--January 31, 2002...Now available from the Stearns Division of Rexnord Corporation is a new series of six totally-enclosed non-ventilated (TENV) armature-actuated electric disc brakes. The Stearns 321 Series AAB brakes are totally-enclosed versions of the Stearns 320 Series brake and are available in the same sizes, with static torque ratings of 3, 5, 7, 15, 35 and 50 lb-in. They are designed for service in dirty or contaminated environments, to decelerate or hold inertial loads when voltage to the brake coil is disconnected. When ordered with optional brake-to-motor gasket, the 321 Series is rated IP-56.
The brakes require no adjustments throughout their service life, and they feature long-life, asbestos-free friction discs. Their low-voltage design will operate in applications that are susceptible to weak battery or brown-out, or with long wiring runs. The new brakes are available in versions that will operate on 12, 24, 48, 90 and 180 VDC, as well as 230 VAC.
Options include a maintained manual release, a carrier ring friction disc for quiet operation, and a Double D friction disc hub. Because this hub design is optional and not required, shaft machining, installation cost and assembly error are reduced in most applications.
The AAB brake design is direct-acting, with only two moving parts. In operation, when electrical power is applied, the armature is pulled by the electromagnetic force in the magnetic body, which overcomes spring action. This allows the friction disc to rotate freely. When electrical power is interrupted, the electromagnetic force is removed, and the pressure spring mechanically forces the armature plate to clamp the friction disc between itself and the pressure plate. This develops the torque needed to stop or hold the load.