The Experts below are selected from a list of 8460 Experts worldwide ranked by ideXlab platform
Valentin Asanbayev - One of the best experts on this subject based on the ideXlab platform.
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The Wound Solid Rotor Circuit Loops: Weak Skin Effect
Alternating Current Multi-Circuit Electric Machines, 2014Co-Authors: Valentin AsanbayevAbstract:Construction of a wound solid Rotor is used primarily in large AC electric machines – for example, in high-power turbo generators, large two-pole synchronous motors, etc. Electromagnetic processes in the wound solid Rotor are determined by the currents induced in the body of the solid Rotor (in the tooth and Rotor joke regions) and currents flowing in the slot wedges and Rotor winding. In the case of the presence of an exciter system, the external current takes place in the Rotor winding. The Rotor winding represents a system of conductors connected in a series, and such current of the same magnitude flows in the Rotor winding conductors. The eddy currents induced in the body of the solid Rotor and slot wedges change in both magnitude and phase. Such characteristics of currents predetermines a fairly complex picture of field distribution in the wound solid Rotor. This chapter is dedicated to a consideration of the wound solid Rotor Circuit loops at a weak skin effect. Here it is assumed that the Rotor winding is powered from an external source (exciter).
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Double-Cage Rotor Circuit Loops: Weak Skin Effect
Alternating Current Multi-Circuit Electric Machines, 2014Co-Authors: Valentin AsanbayevAbstract:Several windings can be located on the Rotor of an induction machine such as a machine with a double-cage Rotor. An induction machine with a double-cage Rotor combines good starting and operating characteristics through the use of starting and working windings on the Rotor. The starting winding has low reactance and relatively high resistance. It corresponds to the squirrel-cage type winding composed of brass or aluminum bars laid at the top of the Rotor slot. The working winding corresponds to the squirrel-cage type winding composed of copper bars laid on the bottom part of the Rotor slot. Such a winding has relatively low resistance. When the machine starts, the currents basically flow in the starting winding. During operation under load conditions, the currents of the slip frequency are induced in the working winding. The effective operation of such an electric machine is enabled by the use of the slit located between the bars of the starting and working Rotor windings. To facilitate this, the starting and working winding bars are laid in place spaced at the height of the Rotor slots. In the electromagnetic regard, an induction machine with a double-cage Rotor is characterized by the presence in the body of the Rotor of a leakage field coupling with the starting and working windings. Therefore, the magnetic field in the double-cage Rotor represents a more complex picture of the distribution. Currently, various forms of interpreting the Rotor leakage field distribution picture exist. In these conditions, establishing the Circuit loops formed by the currents induced in the Rotor windings and determining their impedances become complicated. In this chapter, the Circuit loops of the double-cage Rotor and their impedances are considered under weak skin effect conditions.
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Slotted Solid Rotor Circuit Loops: Weak Skin Effect
Alternating Current Multi-Circuit Electric Machines, 2014Co-Authors: Valentin AsanbayevAbstract:Modern turbo-generators and large high-speed synchronous motors are the most widespread type of AC electric machines with solid Rotors. The solid Rotor of an AC electric machines is performed with the longitudinal slots, in which the insulated distributed winding is placed; the winding is sometimes mono-axial, sometimes biaxial. The solid Rotor can contain a combined system of windings. For example, the Rotor of a turbo-generator can include the insulated distributed winding and also the damper winding (squirrel-cage type winding).
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The Triple-Cage Rotor Circuit Loops: Weak Skin Effect
Alternating Current Multi-Circuit Electric Machines, 2014Co-Authors: Valentin AsanbayevAbstract:In an induction machine, a double-cage Rotor is used to improve the starting characteristics. In the Rotor slots of such electric machine, two conducting bars are placed, separated in the height of the slot by a narrow slit. We should expect an improvement in the characteristics of the electric machine if the space between the upper and lower slot bars is filled with a conducting material. We can thus construct a triple-cage Rotor, in the slots of which are placed three conducting bars located one above the other. The top squirrel-cage type winding performs the starting function. The other two squirrel-cage type windings can be considered the working windings. The lower squirrel-cage type winding serves as the main working winding. The middle squirrel-cage type winding located between the top and lower Rotor windings represents an additional working winding.
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The Squirrel-Cage Solid Rotor Circuit Loops: Weak Skin Effect
Alternating Current Multi-Circuit Electric Machines, 2014Co-Authors: Valentin AsanbayevAbstract:To construct a squirrel-cage solid Rotor, the conducting bars connected at the end parts of the Rotor by conducting rings can be laid in the slots of the solid Rotor. In a Rotor of such construction, the induced eddy currents generally flow in the slot bars, teeth, and Rotor joke region. These currents form a rather complex picture of field distribution in the squirrel-cage solid Rotor. In this chapter, we consider the Circuit loops created by the eddy currents induced in a squirrel-cage solid Rotor and their impedance values at a weak skin effect.
Abdulrahman I. Alolah - One of the best experts on this subject based on the ideXlab platform.
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Smooth starting of slip ring induction motors
IEEE Transactions on Energy Conversion, 1997Co-Authors: M.a. Abdel-halim, M.a.l. Badr, Abdulrahman I. AlolahAbstract:The starting of three-phase wound Rotor induction motors by stepped resistances added in the Rotor Circuit suffers from several problems. This paper suggests a novel method of motor starting by inserting a parallel combination of resistance, inductance and capacitance in the Rotor Circuit. The proposed method guarantees a smooth and high starting torque over most of the starting period besides a controlled starting current. A mathematical model is developed based on a frequency domain quasi-steady state equivalent Circuit. An optimization technique is then applied to determine the values of the Rotor added elements such that minimum starting time is achieved subject to current and torque constraints. Experimental verification has been carried out and the computed results are in good agreement with the measured values.
Daisuke Hiramatsu - One of the best experts on this subject based on the ideXlab platform.
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Modeling of Synchronous Generator and Study on the Load Rejection Characteristics
IEEJ Transactions on Power and Energy, 2006Co-Authors: Daisuke Hiramatsu, Kaoru Koyanagi, Kaiichirou Hirayama, Yoichi Uemura, Mikio Kakiuchi, Susumu Nagano, Ryoma Nagura, Takahiro AraAbstract:The authors have examined the equivalent Circuit of synchronous generator and proposed that the field mutual leakage reactance in Rotor Circuit (Canay reactance) and the saturation of main flux is desirable. This paper describes the study on load rejection characteristic with proposed equivalent Circuit model , using the electromagnetic transients program (ATP-EMTP), and compared the results with the experimental data.
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Study of asynchronizing phenomena using generator model with field mutual leakage reactance
Electrical Engineering in Japan, 2005Co-Authors: Daisuke Hiramatsu, Kaoru Koyanagi, Kaiichirou Hirayama, Yoichi Uemura, Mikio Kakiuchi, T. Satoh, Akahiro AraAbstract:This paper describes the effect of mutual leakage reactance in the Rotor Circuit on the analysis of generator transient characteristics. The authors derive a detailed equivalent Circuit model for a 48P-15,750-kVA generator, analyze sudden short Circuits and asynchronization phenomena of the generator by simulations with an electromagnetic transients program (ATP-EMTP), and compare the results with experimental data. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 31–40, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20147
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Effects of field mutual leakage reactance in Rotor Circuit of synchronous generator on the transient and dynamic behavior
IEEE Power Engineering Society General Meeting 2005, 2005Co-Authors: Susumu Nagano, Daisuke Hiramatsu, Kaoru Koyanagi, Kaiichirou Hirayama, Yoichi Uemura, Mikio Kakiuchi, T. Satoh, Ken NagasakaAbstract:This paper describes the effects of field mutual leakage reactance in Rotor Circuit (Canay reactance) on analysis of generator transient and dynamic behavior. The authors derived a detailed equivalent Circuit model for generator, and analyzed sudden short Circuit out-of-phase synchronization load rejection and sudden load application phenomena of the generator by simulations using the electromagnetic transients program (ATP-EMTP). Then, they compared the obtained results with the experimental data to verify the validity of the proposed equivalent Circuit. In addition to these analyses, the influence of field mutual leakage reactance on analysis of power system dynamic stability was investigated.
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Estimation of field mutual leakage reactance in synchronous machine by line-to-line sudden short Circuit test
IEEE Power Engineering Society General Meeting 2004., 2004Co-Authors: Daisuke Hiramatsu, Kaoru Koyanagi, Kaiichirou Hirayama, Yoichi Uemura, Mikio Kakiuchi, T. Satoh, Ken NagasakaAbstract:This paper describes the effect of field mutual leakage reactance in Rotor Circuit (Canay reactance) on analysis of small or medium capacity generator transient and dynamic behavior .The authors proposed the decision method of field mutual leakage reactance, and analyzed sudden short Circuit and the power system dynamic stability characteristics affected by the Rotor mutual leakage reactance
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Analytical study on synchronizing phenomena using generator model with field mutual leakage reactance
IEEE Power Engineering Society General Meeting 2004., 2004Co-Authors: Daisuke Hiramatsu, Kaoru Koyanagi, Kaiichirou Hirayama, Yoichi Uemura, Mikio Kakiuchi, T. Satoh, Ken NagasakaAbstract:This work describes the effect of mutual leakage reactance in Rotor Circuit (Canay reactance) on analysis of generator transient characteristics. The authors derived a detailed equivalent Circuit model for 48P-15750 kVA generator, and analyzed sodden short Circuit and transient phenomena of the generator at synchronization by simulations using the electromagnetic transients program (ATP-EMTP).
M.a. Abdel-halim - One of the best experts on this subject based on the ideXlab platform.
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Smooth starting of slip ring induction motors
IEEE Transactions on Energy Conversion, 1997Co-Authors: M.a. Abdel-halim, M.a.l. Badr, Abdulrahman I. AlolahAbstract:The starting of three-phase wound Rotor induction motors by stepped resistances added in the Rotor Circuit suffers from several problems. This paper suggests a novel method of motor starting by inserting a parallel combination of resistance, inductance and capacitance in the Rotor Circuit. The proposed method guarantees a smooth and high starting torque over most of the starting period besides a controlled starting current. A mathematical model is developed based on a frequency domain quasi-steady state equivalent Circuit. An optimization technique is then applied to determine the values of the Rotor added elements such that minimum starting time is achieved subject to current and torque constraints. Experimental verification has been carried out and the computed results are in good agreement with the measured values.
P.r.r. Sarma - One of the best experts on this subject based on the ideXlab platform.
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Reduced order models for induction motors with two Rotor Circuits
IEEE Transactions on Energy Conversion, 1994Co-Authors: G. Richards, P.r.r. SarmaAbstract:Induction motor behavior is commonly simulated by a fifth order differential equation model which includes two stator state variables, two Rotor state variables, and shaft speed. Normally two more variables must be added to account for the effects of a second Rotor Circuit representing deep bars, a starting cage, or Rotor distributed parameters. This paper presents a technique for including the effects of a second Rotor Circuit without adding more state variables to the fifth order model. Transient, as well as steady state effects are included. The model may be useful in cases where switching introduces transient torques and losses that are invisible to the fifth order model, and it is not desirable to expand the model to include two more state variables. A laboratory test is included.
