EuroWire Sept 2015

News Technology

Ideal for tension and torque control

Magnetic particle clutches and brakes are suitable for tension and torque control. Clutches are used for rewind tensioning, and torque limiting. Brakes are used for unwind tensioning. Performance, accuracy and life are greater than friction clutches and brakes, since magnetic particle units have no friction plates to wear or give off dust. Slip torque is smooth and infinitely adjustable. Torque is varied from near zero to maximum by varying input current. Units from 1oz inches to 300lb-feet, with heat dissipation up to 1,900 watts continuous duty are available from stock. The DC constant-current power supplies power the clutches, with output current controlled manually with a potentiometer, or by a 0-10 volt signal voltage from a computer or PLC. The Placid Industries follower potentiometer or ultrasonic sensor connects directly to the power supply to make a constant tension unwind system. As the roll diameter decreases, the current energising the brake is decreased to keep tension constant. Placid’s hysteresis brake produces torque without physical contact, ensuring torque is very precise and repeatable, and providing a very long life. Applications include torque and tension control for web handling (unwinding), and load simulation for testing motors and drives.

▲ ▲ Tension and torque control from Placid Industries

Torque can be varied from three per cent to 100 per cent by varying input current. This also provides a very wide RPM range while the cog-buster automatically decogs (eliminates torque ripple) with one revolution. Placid Industries Inc – USA Website : www.placidindustries.com

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September 2015