Oscillating armature drive
Vibrating armature drives are electromagnetic vibration generators that emit linear or arcuate mechanical vibrations.
function
Oscillating armature drives consist of a fixed iron core with an excitation coil and a movable iron core (armature), which is held in the rest position by springs. If a current flows through the excitation coil, the armature is pulled more or less out of the rest position depending on the current strength. Due to the constant change of the current intensity and / or the current direction, the armature gets into a mechanical vibration that can be used for drive purposes. The anchor is often equipped with a permanent magnet ; this increases the efficiency , and the oscillation frequency corresponds to that of the feeding AC voltage.
construction
Since the coil connections would break quickly due to the constant movement, the coil with its core is usually firmly mounted, while the armature has limited mobility. Armature and coil core are usually made of dynamo sheet metal because of the eddy currents that occur . The armature can swing either directly linearly or in an arc-shaped manner around an axis of rotation. The suspension and the armature mass form a spring-mass system with a natural frequency that (when using permanent magnets ) is equal to the alternating voltage (mostly mains frequency, i.e. 50 or 60 Hertz ). In simple systems without magnets (e.g. alternating current bells) the oscillation frequency is twice the feeding frequency .
Operating voltage
Oscillating armature drives are operated with simple devices with AC voltage from the public power grid. For tasks in which an adjustment of the amplitude and frequency is required, converters or similar electronic modules are used that allow easy setting of the corresponding parameters.
properties
Oscillating armature drives are insensitive to overloading (blocking) and have a very long service life, as the service life is only limited by the durability of the suspension elements of the armature and the fatigue of the springs. Their disadvantage is the loud running and the inability to compensate for imbalances , which causes the entire device to vibrate.
application
Oscillating armature drives are widely used wherever short linear back and forth movements are required. The most well-known area of application are devices for personal care, such as. B. razors , hair clippers or massage devices . This type of drive is often used in aquarium pumps ( membrane air pumps ).
In the commercial sector, typical applications are vibratory conveyors , vibrating screens , alternating current bells , alternating current horns , vibration cleaning devices or vibration compressors ( vibrators ).
literature
- Gregor D. Häberle, Heinz O. Häberle: Transformers and electrical machines in power engineering systems. 2nd edition, Verlag Europa-Lehrmittel, Haan-Gruiten, 1990, ISBN 3-8085-5002-3