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BTA® Brushless Torque Actuators

BTA® Brushless Torque Actuators
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BTA® Brushless Torque Actuators Controllable velocity and position Completely enclosed construction Quiet, shock-free operation 100+ million cycle life Excellent unit-to-unit performance consistency ROTARY BTA® Adaptable to closed loop operation All products are RoHS Compliant BTA Principle of Operation The BTA has a single phase coil with three stator poles and matching rotor poles. When the coil is energised, the poles align along the flux path. With the three pole design, it is possible to have a stroke of up to 45°. In practical usage, external stops should be used to attain maximum unit life. Subsequently, the stroke angle is slightly shorter. Use of such mechanical stops also serve to limit the actuator stroke to its optimum stroke/torque capacity. By not requiring full stroke actuation, the BTA offers maximum design flexibility across a wide range of stroke angles and torque requirements. BTA rotary, non-axial stroke actuators are a good solution for applications requiring reliable, low hysteresis operation with a good torque profile as required for proportional operation. Using simple pulse width modulation (PWM) to control coil current, the BTA allows open or closed loop velocity and position control. Such proportional control is ideal for silent, shock-free actuation applications. (In open loop applications, PWM improves hysteresis over variable DC voltage control.) The addition of position feedback, and the subsequent improved system stiffness and accuracy, enables the BTA to be used in closed loop applications. Ledex® Solenoids The bearing system consists of two ball-type bearings which are key to low hysteresis operation. Quiet The BTA can operate virtually noise free. Electronically controlled, the BTA provides soft, shock-free cycling without the noise associated with end-of-stroke mechanical stops. For machines such as the mail sorter pictured at right, which utilises hundreds of these actuators, the BTA is used in conjunction with cushioned external stops to minimise noise and extend the unit’s life to that of the precision ball bearings. Energised www.johnsonelectric.com

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BTA® Brushless Torque Actuators Rapid Cycling The BTA actuator requires only milliseconds to rotate through its entire stroke. It can maintain this extremely fast operating speed repetitively without diminishing accuracy or repeatability, or reducing the overall life of the unit. Rugged The BTA design eliminates the axial travel associated with conventional rotary actuators. In so doing, the BTA eliminates loading on associated mechanical linkages, and reduces the number of moving parts and the wear they receive. The BTA is selfcontained in an industry standard size which enables easy...

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ROTARY BTA® BTA® Selection Brushless Torque Actuators are available in five sizes. Use the selection overview chart to determine which size offers the desired performance and mechanical specifications. Refer to the individual size specification pages for complete performance and mechanical data. Package Gross Starting Torque Gross Ending Torque Dimensions (mNm) @ (mNm) @ (mm) Specified Duty Cycle Specified Duty Cycle Max Dia. Length Stroke 100% 50% 25% 10% 100% 50% 25% 10% All data is at 20°C coil temperature. Torque outputs degrade with elevated temperatures. * Not recommended for 100%...

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