The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform

Yoganata, Yehezkiel Septia - One of the best experts on this subject based on the ideXlab platform.

  • Studi Perbandingan Perilaku Bangunan Menggunakan Sistem Rangka Pemikul Momen, Sistem Rangka Bresing Konsentrik Rangka Bresing Konsentrik Menggunakan Outrigger
    2016
    Co-Authors: Yoganata, Yehezkiel Septia
    Abstract:

    Struktur yang direncanakan harus mampu menghasilkan suatu struktur yang stabil, cukup kuat, mampu-layan, awet, dan memenuhi ketahanan berat gedung, gaya gempa dasar dan perpindahan. Dengan permasalahan yang ada maka perlu adanya suatu sistem yang digunakan pada suatu gedung. Terdapat beberapa sistem yang dapat digunakan untuk menganalisa masalah tersebut. Sebagai bahan studi akan dilakukan perhitungan terhadap variasi tinggi gedung yakni gedung 60, 50, 40, 30 dan 20 lantai dengan tinggi tiap lantai 4 m, panjang dan lebar bangunan 38 m dan 30 m, dan menggunakan tiga sistem yakni sistem rangka pemikul momen khusus ,sistem rangka bresing konsentrik khusus dan sistem rangka bresing konsntrik khusus menggunakan outrigger. Hasil yang diperoleh dari analisa ini, bangunan menggunakan sistem rangka bresing konsentrik khusus menggunakan outrigger lebih kuat terhadap gaya gempa dan perpindahan yang bekerja, dibandingkan dua sistem yang lain, meski dimensi yang dipakai lebih kecil. Hal ini dikarenakan fungsi outrigger untuk mereduksi simpangan lateral dan menahan momen guling. =========================================================== The planned structure must be able to produce a structure that is stable, strong, capable steward, durable, and meets heavy resistance building, basic seismic force, and displacement. With the existing problems it is necessary the existence of a system that is use on a building. There are some systems that can be used to analyze the problem. As study materials will be calculated against height variations that building 60,50,40,30, and 20 floors each floor premises 4 m high, length dan width are 38 m and 30 m, and using three the system bearers special moment resisting frame, special concentrically braced frame, and special concentrically braced frame using outriggers. The resuslts obtained from this analysis, the building uses a special concentrically braced frame using outrigger is stronger against earthquake forces and displacement work than the other two systems, although the dimensions used are smaller than them. This is because the function to reduce the deviation of lateral outrigger and Holding Torque tube

Jorg Wallaschek - One of the best experts on this subject based on the ideXlab platform.

  • piezoelectric ultrasonic motors
    Journal of Intelligent Material Systems and Structures, 1995
    Co-Authors: Jorg Wallaschek
    Abstract:

    Piezoelectric ultrasonic motors are a new type of actuator. They are characterized by high Torque at low rotational speed, simple mechanical design and good controllability. They also provide a high Holding Torque even if no power is applied. Compared to electromagnetic actuators the Torque per volume ratio of piezoelectric ultrasonic motors can be higher by an order of magnitude. Recently various types of piezoelectric ultrasonic motors have been developed for industrial applications such as cameralens drive or as actuator in the head restraint of automobile seats. This paper describes several types of piezoelectric ultrasonic motors. In the first part the working principle of the travelling wave motor is explained. In the second part other types of piezoelectric ultrasonic motors are described and classified with respect to the vibration modes and contact mechanisms used in their design. Finally some open problems in piezoelectric ultrasonic motor research are addressed.

Issam Ttrad - One of the best experts on this subject based on the ideXlab platform.

  • Chopper Control of a Bipolar Stepper Motor
    2013
    Co-Authors: Mahe Dababneh, Walid Ema, Issam Ttrad
    Abstract:

    Low power stepper motors, such as those used in floppy disk drives, are usually powered at low dc voltages, and the value of the motor windings current is usually restricted by the internal resistance of the winding. Very low resistance windings are usually used for building high Torque motors; when powered by any suitable supply voltage, these motors typically require external current limiting circuitry. The requirements for stepper motor drive circuits have changed at a very rapid rate and hence digital integrated circuits have been developed to avoid any complexity and provide facilities to be used in association with microcontrollers. The reduction of discrete circuit components has enhanced the reliability and permitted the use of more sophisticated drive techniques at a reasonable cost [1]. The rotor of a stepper motor usually aligns itself with the stator magnetic field generated by a dc current applied to the stator coils. When the rotor is driven by an external force, a restoring Torque is developed. The Torque becomes maximum when the rotor is turned by one step angle on either direction. This maximum Torque is called the Holding Torque and has the unit of ounce-inche

Johann W Kolar - One of the best experts on this subject based on the ideXlab platform.

  • cogging Torque shape optimization of an integrated generator for electromechanical energy harvesting
    IEEE Transactions on Industrial Electronics, 2017
    Co-Authors: Michael Flankl, Arda Tuysuz, Johann W Kolar
    Abstract:

    In contrast to widely applied cogging Torque (CT) or detent Torque optimization methods, where well-known concepts for achieving a low-ripple Torque as stator and/or rotor skewing are applied, this paper proposes an approach for shaping the stator geometry of a permanent-magnet (PM) synchronous machine, such that an arbitrary CT pattern can be obtained. This is achieved by an iterative algorithm, which adds sinusoidal air gap modulation components on an initial machine geometry. The CT profile is calculated using 2-D FEM simulations, and iterations are repeated until the desired CT pattern is achieved. The proposed approach is applied to an application example, where an outrunner PM generator is integrated in an electromechanical energy harvester (EEH). For this application, the generator's CT is beneficially shaped toward a four-pole sinusoidal pattern with an amplitude of 100 N $\cdot$ mm. The optimized CT of the PM generator is used to counteract the Holding Torque of the EEH, where a reduction in the start-up speed of the EEH by a factor of 4 is observed. Moreover, the presented CT shaping approach is extended beyond the EEH example to illustrate that the described method is also suitable for axially short machines, where skewing is not feasible.

Mahe Dababneh - One of the best experts on this subject based on the ideXlab platform.

  • Chopper Control of a Bipolar Stepper Motor
    2013
    Co-Authors: Mahe Dababneh, Walid Ema, Issam Ttrad
    Abstract:

    Low power stepper motors, such as those used in floppy disk drives, are usually powered at low dc voltages, and the value of the motor windings current is usually restricted by the internal resistance of the winding. Very low resistance windings are usually used for building high Torque motors; when powered by any suitable supply voltage, these motors typically require external current limiting circuitry. The requirements for stepper motor drive circuits have changed at a very rapid rate and hence digital integrated circuits have been developed to avoid any complexity and provide facilities to be used in association with microcontrollers. The reduction of discrete circuit components has enhanced the reliability and permitted the use of more sophisticated drive techniques at a reasonable cost [1]. The rotor of a stepper motor usually aligns itself with the stator magnetic field generated by a dc current applied to the stator coils. When the rotor is driven by an external force, a restoring Torque is developed. The Torque becomes maximum when the rotor is turned by one step angle on either direction. This maximum Torque is called the Holding Torque and has the unit of ounce-inche