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How to be more in control: Torque vs current, AM Series clutches and brakes

How to be more in control: Torque vs current, AM Series clutches and brakes

In life and in machine design, some things are out of our control, and other things we can control. When it comes to power-on clutches and brakes, "torque control" is a matter of varying the power applied. Applying full power will give you full rated torque, while cutting back on the applied current can give your application some flexibility. Small power-on clutches and brakes are used on medical equipment, doors, gates, printing, sorting and inserting, lab equipment, factory automation, and packaging equipment.

Electromagnetic power-on clutches and brakes operate by applying power to a magnetic coil. That creates magnetic flux to attract an armature plate that is connected to the rotating shaft. Stronger current equals more flux, which in turn equals more torque transfer ability. Of course, applying too much power can quickly heat up the device and cause unwanted damage, so torque can be varied by running current below the upper design limit.

If you have a power-on brake application and want to have a controlled stop through a certain applied brake torque, you can use a power controller to provide a specific amount of current to the brake coil. If you have a brake that is holding, but you want to lower the break-away torque in a controlled manner to prevent unwanted consequences, the same theory shall apply. For clutches, the power applied will correlate to the output torque in the same fashion. However, be advised that careful consideration should be taken not to constantly slip these clutches and cause undesired heat build-up and premature failure. There are magnetic particle clutches that are designed for continuous slipping.

AMB and AMC series brakes and clutches have static torque ratings from 2.2 in-lbs (0.25 Nm) to 71 in-lbs (8 Nm). There are other series that offer other torque ranges as well.

Benefits of using Ogura AM series clutches or brakes:

  • Compact design
  • High cycle rates
  • High speed capability
  • Zero backlash designs
  • Current controls torque
  • Fast response times
  • Long life