The Experts below are selected from a list of 9237 Experts worldwide ranked by ideXlab platform
Hamid M.b. Metwally - One of the best experts on this subject based on the ideXlab platform.
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Loadless full load temperature rise test for three phase induction motors
Energy Conversion and Management, 2001Co-Authors: Hamid M.b. MetwallyAbstract:This paper introduces a new method for measuring the full load temperature rise of three phase induction motors. The method is very simple, cheap and reliable. It does not require a mechanical load to be coupled to the motor shaft, as in the conventional method. Also, it does not need any auxiliary machines or special power electronics to generate the two frequency supplies, as needed by the dual frequency method. The method is simply to run the motor at no load without any thing coupled to the shaft but with the supply Voltage slightly higher than the Rated Voltage of the motor. This causes the motor to draw from the supply a no load power higher than that drawn at Rated Voltage. The value of this power can be controlled by changing the applied Voltage to simulate the full load conditions on the motor. The results obtained in this study showed that an input Voltage of about 120% of the Rated Voltage of the motor is a suitable value to cause the full load losses to occur in the motor body, and hence, the full load temperature rise is obtained.
T.a. Lipo - One of the best experts on this subject based on the ideXlab platform.
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B4 topology options for operating three phase induction machines on single phase grids
Twentieth Annual IEEE Applied Power Electronics Conference and Exposition 2005. APEC 2005., 1Co-Authors: T.b. Bashaw, T.a. LipoAbstract:Three-phase (3Phi) induction machines are known for their advantages over the single-phase (1Phi) version regarding efficiency, and torque pulsations. Variable and line frequency operation of 3Phi; induction machines on 1Phi; lines, as opposed to using 1Phi machines, has been plagued by the cost issues concerning the number of semiconductor drivers and the amount of capacitance in the DC link. Traditionally, six-switch PWM methods are used to drive 3Phi machines. In this paper four-switch PWM methods (B4) featuring new interconnections are proposed that provide variable and line frequency operation of 3Phi machines on 1Phi grids. For static, i.e. diode rectification, a Voltage doubler circuit is often used instead of a full wave rectifier, since it allows for twice the DC link Voltage, which is necessary for operating the induction machine at up to Rated Voltage when utilizing the B6 topology. Current utilization of B4 topologies only allow for driving induction machines at about half of their Rated Voltage when using static rectification. In this paper, theoretical, simulated, and experimental results are presented that incorporate effects of finite supply capacitance utilizing a static Voltage doubler circuit for alternative utilizations of the B4 under line frequency excitation that allow for operation at full-Rated Voltage
Chen Longjing - One of the best experts on this subject based on the ideXlab platform.
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the insulating fire resisting cable of Rated Voltage 10kv crosslinkedpolyethylene
2015Co-Authors: Xiao Yuntao, Liu Shuquan, Li Henggang, Gao Jiangtao, Chen LongjingAbstract:The utility model relates to the technical field of cables, the concrete insulating fire resisting cable of a Rated Voltage 10kV crosslinked polyethylene that discloses, include many cable cores and set gradually band layer, flame retardant coating and the oversheath layer outside the cable core, the cable core includes conductor and internal shield layer, insulating layer, external shielding layer and the iron shielded layer of cladding outside the conductor in proper order, separate through the filler between the cable core. The utility model discloses the advantage is, the cable safety performance is higher, can improve the service reliability of power supply system under the fire environment, has guaranteed reliability of power supply under the fire condition, and the evacuation that is favorable to personnel is withdrawn and is carry out with the rescue.
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the insulating fire resistant armoured cable of Rated Voltage 10kv ep rubbers
2015Co-Authors: Xiao Yuntao, Liu Shuquan, Li Henggang, Gao Jiangtao, Chen LongjingAbstract:The utility model relates to the technical field of cables, the concrete insulating fire-resistant armoured cable of a Rated Voltage 10kV EP rubbers that discloses, include many cable cores and set gradually band layer, flame retardant coating, isolation layer, armor and the oversheath layer outside the cable core, the cable core includes conductor and internal shield layer, insulating layer, external shielding layer and the iron shielded layer of cladding outside the conductor in proper order, separate through the filler between the cable core. The utility model discloses the advantage is, the cable safety performance is higher, can improve the service reliability of power supply system under the fire environment, has guaranteed reliability of power supply under the fire condition, and the evacuation that is favorable to personnel is withdrawn and is carry out with the rescue.
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the insulating fire resistant armoured cable of Rated Voltage 10kv crosslinkedpolyethylene
2015Co-Authors: Xiao Yuntao, Liu Shuquan, Li Henggang, Gao Jiangtao, Chen LongjingAbstract:The utility model relates to the technical field of cables, the concrete insulating fire-resistant armoured cable of a Rated Voltage 10kV crosslinked polyethylene that discloses, include many cable cores and set gradually band layer, flame retardant coating, isolation layer, armor and the oversheath layer outside the cable core, the cable core includes conductor and internal shield layer, insulating layer, external shielding layer and the iron shielded layer of cladding outside the conductor in proper order, separate through the filler between the cable core. The utility model discloses the advantage is, the cable safety performance is higher, can improve the service reliability of power supply system under the fire environment, has guaranteed reliability of power supply under the fire condition, and the evacuation that is favorable to personnel is withdrawn and is carry out with the rescue.
Ok-bae Hyun - One of the best experts on this subject based on the ideXlab platform.
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Rated-Voltage enhancement by fast-breaking of the fault current for a resistive superconducting fault current limiter component
Physica C: Superconductivity and its Applications, 2010Co-Authors: C.-r. Park, M.-j. Kim, S.-w. Yim, Hye-rim Kim, Ok-bae HyunAbstract:Abstract Performance of a resistive superconducting fault current limiter (SFCL) component is usually limited by temperature rise associated with energy input by fault current application during a fault. Therefore, it is expected that short application of the fault current may enhance the power ratings of the component. This can be accomplished by a combination of a HTS component and a mechanical switch. The fast switch (FS) developed recently enables the fault duration to be as short as 1/2 cycle after a fault. Various second-generation (2G) high temperature superconductors (HTS) and YBCO thin films have been tested. The relation between the Rated Voltage V and the fault duration time t was found to be V 2 ∼ t − 1 . Based upon the relation, we predict that when the FS break the fault current within 1/2 cycle after a fault, the amount of HTS components required to build an SFCL can be reduced by as much as about 60%, of that when breaking the fault current at three cycles.
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14 kV single-phase superconducting fault current limiter based on YBCO films
Cryogenics, 2007Co-Authors: J. Sim, Hye-rim Kim, K.b. Park, J.s. Kang, Bang-wook Lee, Ho Min Kim, Ok-bae HyunAbstract:Abstract We present the fabrication and short circuit test results of a 14 kV single-phase resistive superconducting fault current limiter (SFCL) based on YBa 2 Cu 3 O 7 (YBCO) films. Individual components were processed using the 4″ YBCO films and have the Rated Voltage and current of 600 V and 35 A at 77 K, respectively. Twenty four components, eight components in series and three lines in parallel, make a module having the Rated Voltage and current of 4.8 kV and 105 A, respectively. Three modules were assembled in series to produce the SFCL working at 77 K, a 14 kV single-phase machine for the 22.9 kV Y–Y grid. short circuit tests were successfully conducted in an accredited test facility with the maximum fault currents up to 14.1 kA P . All components quenched together upon faults and shared the Rated Voltage evenly without any supplementary device between the modules. This proves that the SFCL based on YBCO films may not only work reliably at 22.9 kV, but also provide technical feasibility for higher Voltage application including the transmission grids.
T.b. Bashaw - One of the best experts on this subject based on the ideXlab platform.
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B4 topology options for operating three phase induction machines on single phase grids
Twentieth Annual IEEE Applied Power Electronics Conference and Exposition 2005. APEC 2005., 1Co-Authors: T.b. Bashaw, T.a. LipoAbstract:Three-phase (3Phi) induction machines are known for their advantages over the single-phase (1Phi) version regarding efficiency, and torque pulsations. Variable and line frequency operation of 3Phi; induction machines on 1Phi; lines, as opposed to using 1Phi machines, has been plagued by the cost issues concerning the number of semiconductor drivers and the amount of capacitance in the DC link. Traditionally, six-switch PWM methods are used to drive 3Phi machines. In this paper four-switch PWM methods (B4) featuring new interconnections are proposed that provide variable and line frequency operation of 3Phi machines on 1Phi grids. For static, i.e. diode rectification, a Voltage doubler circuit is often used instead of a full wave rectifier, since it allows for twice the DC link Voltage, which is necessary for operating the induction machine at up to Rated Voltage when utilizing the B6 topology. Current utilization of B4 topologies only allow for driving induction machines at about half of their Rated Voltage when using static rectification. In this paper, theoretical, simulated, and experimental results are presented that incorporate effects of finite supply capacitance utilizing a static Voltage doubler circuit for alternative utilizations of the B4 under line frequency excitation that allow for operation at full-Rated Voltage
