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Simulation, design and experimental validation of a passive magnetic damper for ultra-fast actuators
KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
2014 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

A contact system driven by a high energetic Thomson actuator requires to be decelerated from

full speed down to zero. The forces originated from the interaction between a stationary

copper tube and a moving array of magnets combined with plastic or ferromagnetic material

are used to generate eddy-current damping. Five different configurations of small but strong

(N52) neodymium magnets and spacers were benchmarked for simple free-fall damping. A

comparison between experimental results and simulations (using COMSOL) has shown that

the most effective damping is reached by two consecutive permanent magnets with opposite

magnetization directions ,separated by low-carbon content steel concentrators(SN - Fe

concentrator- NS).

The proposed damper design is the result of the balance between various parameters such as

magnet orientation topology in the array, spacer material and its dimensions, copper tube

thickness and the air gap between copper tube and array.

Furthermore, the design was scaled up and an actuator-drive system was added to perform

more realistic tests, which demonstrated the damping effectiveness on a fast moving armature

actuated by a Thomson coil energized by a capacitor bank. All models in the simulation

predicted the damping effect in advance. Investigations were conducted with two cases: (1) A

solid copper rod was supposed to pass through the magnet array; (2) A plastic shaft was

applied to support the magnet array.

Finally a damping prototype with a plastic shaft was built for completing damping tests. The

results of these tests validated the numerical model with a high degree of accuracy.

Place, publisher, year, edition, pages
2014. , 75 p.
EES Examensarbete / Master Thesis, XR-EE-ETK 2014:005
Keyword [en]
Damping, Thomson actuator, eddy currents, magnets, ferromagnetic materials
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
URN: urn:nbn:se:kth:diva-153639OAI: diva2:752783
Educational program
Master of Science - Electric Power Engineering
Available from: 2014-10-06 Created: 2014-10-06 Last updated: 2014-10-06Bibliographically approved

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