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At least 937 records · Page 52

Experiments in 3D Printing Electric Motors

This paper catalogues a series of experiments we conducted to explore how to 3D print a DC electric motor. The individual parts of the electric motor were 3D printed but assembled by hand. First, we focused on a rotor with soft magnetic properties, for which we adopted ProtoPasta TM , which is a commercial off-the-shelf PLA filament incorporating iron particles. Second, we focused on the stator permanent magnets, which were 3D printed through binder jetting. Third, we focused on the wire coils, for which we adopted a form of laminated object manufacture of copper wire. The chief challenge was in 3D printing the coils, because the winding density is crucial to the performance of the motor. We have demonstrated that DC electric motors can be 3D printed and assembled into a functional system. Although the performance was poor due to the wiring problem, we showed that the other 3D printing processes were consistent with high performance. Nevertheless, we demonstrated the principle of 3D printing electric motors.

3D printed motor↗

A bacterial membrane sculpting protein with BAR domain-like activity

Bin/Amphiphysin/RVS (BAR) domain proteins belong to a superfamily of coiled-coil proteins influencing membrane curvature in eukaryotes and are associated with vesicle biogenesis, vesicle-mediated protein trafficking, and intracellular signaling. Here, we report a bacterial protein with BAR domain-like activity, BdpA, from Shewanella oneidensis MR-1, known to produce redox-active membrane vesicles and micrometer-scale outer membrane extensions (OMEs). BdpA is required for uniform size distribution of membrane vesicles and influences scaffolding of OMEs into a consistent diameter and curvature. Cryo-TEM reveals that a strain lacking BdpA produces lobed, disordered OMEs rather than membrane tubules or narrow chains produced by the wild-type strain. Overexpression of BdpA promotes OME formation during planktonic growth of S. oneidensis where they are not typically observed. Heterologous expression results in OME production in Marinobacter atlanticus and Escherichia coli . Based on the ability of BdpA to alter membrane architecture in vivo, we propose that BdpA and its homologs comprise a newly identified class of bacterial BAR domain-like proteins.

60 APPLIED LIFE SCIENCES↗

Magnetically Diffused Radial Electric-Arc Air Heater Employing Water-Cooled Copper Electrodes

A magnetically rotated electric-arc air heater has been developed that is novel in that an intense magnetic field of the order of 10,000 to 25,000 gauss is employed. This field is supplied by a coil that is connected in series with the arc. Experimentation with this heater has shown that the presence of an intense magnetic field transverse to the arc results in diffusion of the arc and that the arc has a positive effective resistance. With the field coil in series with the arc, highly stable arc operation is obtained from a battery power supply. External ballast is not required to stabilize the arc when it is operating at maximum power level. The electrode erosion rate is so low that the airstream contamination is no more than 0.07 percent and may be substantially less.

COPPER↗

Extendible column can be stowed on drum

Column formed from a series of segments held together by an internal spring or cable can be coiled on a drum or extended into a rigid structure. This storable coil is useful in boring for soil samples and supporting electrical and optical sensors.

Holtz, G. M.↗

Feed-through connector couples RF power into vacuum chamber

Feed-through device connects RF power to an RF coil in a vacuum chamber. The coil and leads are water cooled and vacuum tight seals are provided at the junctions. The device incorporates silver soldered copper tubes, polytetrafluoroethylene electrical insulators, and O-ring vacuum seals.

Grandy, G. L.↗

Environmental control system for cryogenic testing of tensile specimens

Environmental control system uses a special coil to permit the tensile testing of specimens which may be subjected to temperatures anywhere between liquid nitrogen and room temperature. The test specimen zone is surrounded by the coil which permits the selective flooding of the specimen with warm or cold gas.

Vandergrift, E. F.↗

Low-cost, fast-response drive circuit for electromagnetic torque motors

Fast-response coil drive circuit, for electromagnetic torque motors, reduces the inductive coil time constant with a minimum of circuit sophistication. The low-cost modulator servoamplifier is used with a compatible preamplifier stage which provides the servo-loop function of summing, adjustable gain and compensation.

Zeller, J. R.↗

An improved Orbitron ionization gage measures ultrahigh vacuum

Ionization gage with improved signal-to-noise ratio has a helical coil electrode which separates the solid cathode ion collector from the volume where ionization of gas molecules takes place. Helical coil increases lifetime of electrons and reduces secondary emission from the collector.

Gosselin, C. M.↗

Device measures conductivity and velocity of ionized gas streams

Coaxial arrangement of primary coil and two sensing secondary coils contained inside slender quartz tube inserted into ionized stream permits simultaneous determination of conductivity and linear velocity. System results agree favorably with theory.

Cook, G. R.↗

SSA-A spacecraft magnetic tests

In the initial magnetic tests the spacecraft perm moment as received was 43 milliampere-meter squared (pole-cm), which was reduced by deperm treatment to milliampere-meter squared. Facility fluxgate probe bias results indicated Z axis bias at the SSS-A fluxgate magnetometer position to be about one half nanotesla (gamma) after Z axis deperm. The ASCS magnetometers, 01 and 02, were successfully aligned and proper operation of the ASCS system were verified. The spacecraft fluxgate magnetometer was calibrated in both the high and low sensitivity modes after a defective 01 electronics card was replaced. Problems were encountered in the Z axis search coil during calibration and the test was re-scheduled. Final test results indicated that the total perm moment could not be reduced any lower than 35 milliampere-meter squared by deperm treatment. However, the Z axis moment decreased from 22 milliampere-meter squared to 6 milliampere-meter squared after deperm. Correct operation and calibration was verified for all three axes of the spacecraft fluxgate magnetometer and no significant bias was observed during stray field testing. Null and spot calibration of the ASCS magnetometer was completed and the measured spin and attitude coil moments were: 2535 and 9820 milliampere-meter squared respectively.

Roy, T. N.↗

UK-4 prototype spacecraft magnetic tests

The spacecraft was tested in a magnetic test facility which uses a 42 ft. diameter coil system to produce a controlled magnetic field of high uniformity over a large central volume. The primary objectives of the tests were: (1) to determine the permanent, induced, and stray magnetic moments of the spacecraft and to assess its magnetic stability; (2) to evaluate the magnetorquer coil system; and (3) to deperm, compensate, and make other adjustments necessary to achieve satisfactory magnetic characteristics for the spacecraft. The test facility and procedures are described together with the results obtained. In addition, the problems encountered during the tests and the significance of the test findings are discussed.

Pruett, W. E.↗

Terrestrial adaptation of the thermal heliotrope.

The principle of using bimetal helical coils to cause solar arrays to track the sun in space is presently under consideration for array orientation on several spacecraft. Adaptation of this thermal heliotrope to terrestrial applications introduces additional design considerations. The dominance of solar-radiation energy input to the helical coil over convective energy losses has to be ensured, and wind effects must be minimized. As long as the cost of solar cells remains high, orientation will always result in a significant cost saving for the converter.

Fairbanks, J. W.↗

Bimetallic devices for stirring fluids

Device consists of helical heating coil inside cylinder and affixed at one end. Piston is fastened at other end and is free to move axially through cylinder. Electrical power extends coil when applied to conductors. Bimetallic stirrer may also be made in vane form.

Canning, T. N.↗

Stabilizing a gaseous optical laser

Frequency of gaseous optical laser can be stabilized by sinusoidally modulating the geometry of the cavity. Fabry-Perot dielectric mirrors are mounted in two Invar blocks that are connected by four magnetorestrictive bars. Each bar has three coils to sinusoidally modulate system. Ac establishes frequency, and dc the average value; both are supplied to coil from control system.

Jauan, A.↗

Electromagnetic position sensor for a magnetically supported model in a wind tunnel

An investigation was undertaken to determine the feasibility of using superconducting force-producing coils for positioning a model in a wind tunnel. The cryostat containing the forcing coils surrounded the test section of the tunnel, thus favoring an electromagnetic position sensor. Another reason favoring this choice was the fact that the performance of an electromagnetic sensor is essentially unaffected by the shape of the model.

Towler, W. R.↗

NASA superconducting magnetic mirror facility

The design details and initial test results of a superconducting magnetic mirror facility that has been constructed at NASA Lewis Research Center for use in thermonuclear research are summarized. The magnet system consists of four solenoidal coils which are individually rated at 5.0 T. Each coll is composed of an inner, middle, and outer winding. The inner winding is wound of stabilized Nb3Sn superconducting ribbon, and the middle and outer windings are wound of stabilized Nb-Ti superconducting wire. When arranged in the mirror geometry, the four coils will produce 8.7 T at the mirrors and a 1.8 mirror ratio. The magnet has a 41-cm diameter clear bore which is open to atmosphere. Distance between the mirrors is 111 cm. Presently there are only three magnets in the facility; the fourth magnet is being rebuilt.

Reinmann, J. J.↗

Heat operated cryogenic electrical generator

An electrical generator useful for providing electrical power in deep space, is disclosed. The electrical generator utilizes the unusual hydrodynamic property exhibited by liquid helium as it is converted to and from a superfluid state to cause opposite directions of rotary motion for a rotor cell thereof. The physical motion of the rotor cell was employed to move a magnetic field provided by a charged superconductive coil mounted on the exterior of the cell. An electrical conductor was placed in surrounding proximity to the cell to interact with the moving magnetic field provided by the superconductive coil and thereby generate electrical energy. A heat control arrangement was provided for the purpose of causing the liquid helium to be partially converted to and from a superfluid state by being cooled and heated, respectively.

Wang, T. G.↗