Transition in brush armatures

Schneider, M.; Eckenfels, D.; Hatterer, F.

doi:10.1109/tmag.2002.805904

Cited by 46 publications

(34 citation statements)

References 11 publications

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“…At the start of this paper, the railgun was equipped with rectangular rails of CuCr and the projectile type described in [8]. The first important improvement was triggered by the observation that during a shot the current switched in forward direction between the brushes starting at the rear brush [8].…”

Section: Improving Ema3 With Respect To Contact Performancementioning

confidence: 99%

“…The first important improvement was triggered by the observation that during a shot the current switched in forward direction between the brushes starting at the rear brush [8]. The concept of a separating sabot (Section III-A) makes use of this behavior.…”

Section: Improving Ema3 With Respect To Contact Performancementioning

confidence: 99%

“…The first experiments were performed back in 2001 using an "inherited" sabot-brush configuration [8]. With the aid of the newly introduced Doppler radar technique [10], it was shown that in the case of multiple-in shot direction separated-brush armatures the following switching mechanism takes place.…”

Section: A Separating Sabot Techniquementioning

confidence: 99%

“…With the aid of the newly introduced Doppler radar technique [10], it was shown that in the case of multiple-in shot direction separated-brush armatures the following switching mechanism takes place. At a certain point the rear brush is disconnected from the rails due to insufficient length and the current previously passing through it is switched to other brushes still in contact with the rails [8]. The process is repeated for each "new" rear brush.…”

Section: A Separating Sabot Techniquementioning

confidence: 99%

“…As pointed out, on several occasions [8], [9], the contact transition of metal fiber brushes is strongly driven by material loss which itself depends on both Joule heating at the contact interface and frictional wear. Taking the latter into account, a rail design termed "quasi-segmented rails" was introduced in [10].…”

Section: B Adapted Rail Configurationmentioning

confidence: 99%

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Advanced Rail-Sabot Configurations for Brush Armatures

Schneider

2007

IEEE Trans. Magn.

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This paper reports on experimental results obtained at the ISL-railgun facility EMA3 (muzzle velocity 0 2 km/s, applied energy per shot prim 1 MJ, = 3 m, regular cal. = 15 mm 30 mm, (multiple) metal fiber brush armatures) from 2001 to 2005. Several techniques with the aim of investigating contact performance up to 2 km/s were developed during this period. These techniques include: 1) quasi-segmented and wedge shaped rail configurations, which vary the width of the rail as a function of the rail length in order to maximize the performance of multiple brush armatures; 2) separating sabot technique, for which the latest experimental results and some calculated figures of merit based on a simple model are presented; and 3) new contact materials for solving the problem of gouging at very high contact transition velocities. Some experimental results obtained with brush armatures are presented. The paper concludes by presenting detailed results of a representative shot combining all of the mentioned techniques and clearly demonstrating their capacities. A lower limit of the contact transition velocity of 1800 m/s has been observed, increasing the previously observed value of 1100 m/s significantly.

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Section: Improving Ema3 With Respect To Contact Performancementioning

confidence: 99%

Section: Improving Ema3 With Respect To Contact Performancementioning

confidence: 99%

Section: A Separating Sabot Techniquementioning

confidence: 99%

Section: A Separating Sabot Techniquementioning

confidence: 99%

Section: B Adapted Rail Configurationmentioning

confidence: 99%

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Advanced Rail-Sabot Configurations for Brush Armatures

Schneider

2007

IEEE Trans. Magn.

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Pulsed magnetic field measurement system based on colossal magnetoresistance-B-scalar sensors for railgun investigation

Stankevič

Medišauskas

Stankevič

et al. 2014

Review of Scientific Instruments

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A high pulsed magnetic field measurement system based on the use of CMR-B-scalar sensors was developed for the investigations of the electrodynamic processes in electromagnetic launchers. The system consists of four independent modules (channels) which are controlled by a personal computer. Each channel is equipped with a CMR-B-scalar sensor connected to the measurement device-B-scalar meter. The system is able to measure the magnitude of pulsed magnetic fields from 0.3 T to 20 T in the range from DC up to 20 kHz independently of the magnetic field direction. The measurement equipment circuit is electrically separated from the ground and shielded against low and high frequency electromagnetic noise. The B-scalar meters can be operated in the presence of ambient pulsed magnetic fields with amplitudes up to 0.2 T and frequencies higher than 1 kHz. The recorded signals can be transmitted to a personal computer in a distance of 25 m by means of a fiber optic link. The system was tested using the electromagnetic railgun RAFIRA installed at the French-German Research Institute of Saint-Louis, France.

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Development of a low voltage railgun in the context of a swept lightning stroke on an aircraft

Andraud

Martins

Zaepffel

et al. 2022

Review of Scientific Instruments

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When aircraft are struck by lightning, the aircraft’s structural fuselage and components are stressed by electrical and thermo-mechanical constraints, which imposes a need for reliable experimental test benches to design accurate and enhanced lightning protection. In order to reproduce the in-flight conditions of an aircraft in a laboratory, the aim of this work is to design and implement launch equipment able to propel aeronautical test samples at speeds characteristic of an aircraft— from 10 m/s for ultra-light gliders to 100 m/s for airliners—before striking it with an electric arc within the laboratory dimensions of several meters. After a comparison of several propulsion techniques, the selected solution is an augmented electromagnetic railgun launcher. Since it requires the injection of a high current to be efficient and a low voltage operative point for safety considerations, specific and original electric generator and rail structures have been designed and experimentally implemented. Particular attention has been paid to the experimental problems encountered and mainly the sliding contact, since almost no literature references are available for railgun equipment at this level of performance. Then, based on different experimental implementations, a dynamic and ballistic model of the projectile has been developed to evaluate and characterize friction forces with the aim of predicting launcher performances with different inputs. This serves to control the speed of the material test sample during the lightning strike. Finally, the railgun equipment has been coupled to a lightning generator to reproduce the lightning strike of an aircraft respecting in-flight conditions.

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Transition in brush armatures

Cited by 46 publications

References 11 publications

Advanced Rail-Sabot Configurations for Brush Armatures

Advanced Rail-Sabot Configurations for Brush Armatures

Pulsed magnetic field measurement system based on colossal magnetoresistance-B-scalar sensors for railgun investigation

Development of a low voltage railgun in the context of a swept lightning stroke on an aircraft

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