Magnetic powder clutches transmit torque through controllable magnetic bonding between particles. They are widely used when smooth, adjustable torque transfer is required—especially in tension control applications for bag-making machines, film production, and cable winding.
This article explains the working principles, characteristics, and key applications for equipment designers.
1. Basic Structure of a Magnetic Powder Clutch
Main components:
- Input rotor (driving side)
- Output rotor (driven side)
- Magnetic powder filling the gap
- Electromagnetic coil
Unlike brakes, clutches transfer torque between two rotating components.
Suggested diagram:
- Show input side, output side, powder gap, magnetic flux linkage
2. Working Principle
When the coil is energized:
- Magnetic flux aligns the powder into chain-like structures.
- These structures transmit torque between the input and output rotors.
- Torque level is directly proportional to coil current.
- When current decreases, the powder releases and torque falls smoothly.
This controllable torque transfer is why powder clutches excel in tension control systems.
3. Advantages of Magnetic Powder Clutches
Smooth Engagement
Unlike mechanical clutches, engagement is gradual and shock-free.
High Torque Accuracy
Torque is stable even at low speed and low tension.
Wide Torque Control Range
Suitable for processes requiring delicate tension adjustments.
Long Life & Low Wear
Minimal mechanical contact reduces wear.
4. Applications
- Bag-making machines（film feed control）
- Printing and labeling machines
- Wire & cable winding
- Paper converting machinery
- Film extrusion and slitting
- As torque limiters in test equipment
Clutches are used on the driving side of a tension system, while powder brakes are used on the unwinding side.
5. How to Select a Powder Clutch
Consider:
- Required torque
- Input shaft capacity
- Thermal load
- Duty cycle
- Required responsiveness
POC / POB models are typically selected based on shaft type and mounting direction.
Conclusion
Magnetic powder clutches provide precise, smooth torque transmission, making them essential in high-performance tension control and automation systems.
