Voice coil actuators
Voice Coil Actuators are Linear DC motors. They consist of 2 main components, the coil assembly and the magnetic mass. By applying a voltage across the 2-wire connection of the actuator it will move in one direction. Consequently, reversing the polarity of the applied voltage will move the actuator in the opposite direction. Moreover, the generated force is proportional to the current that flows through the coil. This force is almost constant in the specified stroke range of the actuator.
Voice coil Actuators are brushless and do not require commutation. Their structural stability can support high positioning resolutions presented by external position sensors and motion controllers. The non-commutated actuator construction increases reliability. Furthermore, due to direct coupling of the motor to the load it allows for fast acceleration / deceleration and high speed operation.
types of Voice coil actuators
There are 2 main types of voice coil actuators, moving magnet actuators and moving coil actuators. As the name implies, for moving magnet actuators the coil is fixated and the magnet moves. As for the moving coil actuator the magnet core is fixed and the coil moves. Magnetic Innovations specializes in moving magnet actuators. Due to the lack of moving wires, they are very reliable and durable. Furthermore they can achieve much higher force densities as moving coil actuators as the moving magnet actuators can be actively cooled.
Cooling a moving magnet actuator is easy. The fact that the coil assembly is on the outer diameter of the device makes it possible to integrate it into a water cooling sleeve. Also, it is possible to cool it by using forced air to blow across the coil assembly or simply mount it inside a heatsink. As a result, cooling will substantially extend the performance of the device.
Moving magnet actuators come in a variety of versions. Frameless, with integrated slide bearings and/or with linear positioning sensor. In case of a frameless actuator the moving part needs to be supported by bearings supplied by the customer.
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