AND DRIVE SYSTEMS SECOND EDITION. ANALYSIS OF ELECTRIC MACHINERY. Paul C. Krause. Oleg Wasynczuk. Scott D. Sudhoff. Lilansformation. Analysis of Electric Machinery and Drive Systems, Third Edition. Editor(s). Paul Krause; Oleg Wasynczuk; Scott Sudhoff; Steven Pekarek. Krause, Paul C. Analysis of electric machinery and drive systems / Paul Krause, Oleg Wasynczuk, Scott Sudhoff, Steven. Pekarek. – Third edition. pages cm.
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ANALYSIS OF ELECTRIC MACHINERY AND DRIVE SYSTEMS Secorrd Edition. PAUL C. KRAUSE OLEG WASiYNCZUK. SCOTT D. SUDHOFF. Analysis of electric machinery and drive systems. Francisco Javier Medina Rosas . F. Medina Rosas. Loading Preview. Sorry, preview is currently unavailable. Below is the excellent place to get Analysis Of Electric Machinery And Drive Systems Pdf by garfstontanguicon.ga Study completely free. Everybody enables.
The power may be expressed as P1: Hence using IA-1 again we obtain 1 22 30 X 1 d: This may be deter- mined as follows: In summary, A transformer is generally designed so that some saturation occurs during normal operation. Electric machines are also designed similarly in that a machine generally operates slightly in the saturated region during normal, rated operating conditions.
Our purpose here is not to set forth methods of analyzing nonlinear magnetic systems. This pro- cedure is quite straightforward for steady-state operation, but it cannot be used when analyzing the dynamics of electromechanical devices . A method of incorporating the effects of saturation into a computer representation is of interest. Computer Simulation of Coupled Circuits Formulating the voltage equations of stationary coupled windings appropriate for computer simulation is straightforward and yet this technique is fundamental to the computer simulation of ac machines.
Therefore it is to our advantage to consider this method here. In the com- puter simulation, 1. The currents can then be obtained from 1. It is clear that 1. From Fig. In particular, f Am is a function of Am as shown in Fig. It is desirable, however, to establish methods of analysis that may be applied to all electromechanical devices. Energy Relationships Electromechanical systems are comprised of an electrical system, a mechanical sys- tem, and a means whereby the electrical and mechanical systems can interact.
An electromechanical system with one electrical system, one mechanical system, and Losses occur in all components of the electromechanical system. Heat loss will occur in the mechanical system due to friction, and the electrical system will dissi- pate heat due to the resistance of the current-carrying conductors. The energy WeL is the heat losses associated with the electrical system. It is important to note that with the convention adopt- , d, the energy supplied by either source is considered positive.
Therefore, WE WM. The system shown in Fig. In these systems, v is the voltage of the electric source and f is the external mechanical force applied to the mechanical system.
The electromagnetic or electrostatic force is denoted by fe. The resistance of the current-carrying conductors is denoted by r, and I is the induc- tance of a linear conservative electromagnetic system that does not couple the mechanical system.
In the mechanical system, M is the mass of the movable member while the linear compliance and damper are represented by a spring constant K and a Figure 1. The displacement x0 is the zero force or equili- brium position of the mechanical system which is the steady-state position of the mass with fe and f equal to zero.
The voltage equation that describes both electrical systems may be written as. The second term is the heat loss due to friction WmL.
Considering the system shown in Fig. Zee-1, dt —: Once we have an expression for Wf, we can take the total derivative to obtain dWf, which can then be substituted into 1. Because air is a conservative medium, all of the energy stored therein can be During the excitation of the electrical systems, Wmk is zero even though electroma- gnetic or electrostatic forces occur.
The area to the left of the A—i relationship shown in Fig. In Fig. There- fore, either A and x or i and x may be selected as independent variables. Thus from 1. Substituting into 1. The coenergy in terms of i and x may be evaluated from 1. For example, 1. To illustrate the evaluation of 1.
This procedure may be illustrated by considering a doubly excited electric system with one mechan- ical input. An electromechanical system of this type could be constructed by placing a second coil, supplied from a second electrical system, on either the stationary or movable member of the system shown in Fig. In this evaluation it is conve- nient to use currents and displacement as the independent variables. First we will mathematically bring the current i1 to the desired value while holding i2 at zero.
As the second evaluation of 1.
Following this two-step procedure the evaluation of 1. The second integral comes from the second step of the evaluation with i1: The results would be the same. Let us now evaluate the energy stored in a magnetically linear electromechanical system with two electrical inputs and one mechanical input.
Appropriate substitution into 1. EL11 11 ;?
W, - 11,. ELpqlplq For this purpose let us again refer to the elementary system shown in Fig. It is clear that the exact trajectory from A to B is determined by the combined dynamics of the electrical and mechanical systems. If the trajectory had been in the counterclockwise direction, the net AWE would have been positive and the net AW, " would have been negative, which would represent motor action. One is tempted to substitute the integrand of 1. This procedure is, of course, incorrect because the integrand of 1.
The force or torque in any electromechanical system may be evaluated by employing In many respects, one gains a much better understanding of the energy conversion process of a particular system by starting the derivation of the force or torque expressions with 1.
However, for the sake of completeness, derivation of the force equa- tions will be set forth and tabulated for electromechanical systems with K mechan- ical inputs and J electrical inputs .
For an electromagnetic system, 1. The index n is used so as to avoid confusion with the index j because each dlj must be evaluated for changes in all currents in order to account for mutual coupling between electrical systems.
A second force equation with 1', and xk as independent variables may be obtained from 1. For a multiexcited system the coenergy may be expressed as.
It should be recalled that positive fe, and positive dx , are in the same direction. These relations are given in Table 1. In Table 1. In particular, when considering a rotational system, f, ,;, is replaced with the electromagnetic torque Tek, and x1 is replaced with the angular displace- ment These relationships are given in Table 1.
It is instructive to derive the expression for the electromagnetic force of a singly excited electrical system as shown in Fig. It is clear that the expressions given in Table 1. In particular, feaax: With the convention established, a positive electromagnetic force is assumed to act in the direction of increasing x. Thus with 1. In the electromechanical system shown in Fig. In other words, an electromagnetic force is set up so as to maximize the inductance of the coupling system, or, since reluctance is inversely proportional to the induc- tance, the force tends to minimize the reluctance.
Because f, is always negative in the system shown in Fig.
Steady-State and Dynamic Performance of an Electromechanical System It is instructive to consider the steady-state and dynamic performance of the elemen- tary electromagnetic system shown in Fig. The differential equations that describe this system are given by 1. The electromagnetic force f, is expressed by 1. If the applied voltage, v, and the applied mechanical force, f, are constant, all Nevertheless, 1. The straight lines represent the right-hand side of 1.
Both lines intersect the —f. Stable operation occurs at only points 1 and 2. If x increases beyond its value corresponding to operating point 1, the restraining force is less than the electromagnetic force. Therefore, the system will establish steady-state operation at 1. If, on the other hand, x decreases As a Chegg Study subscriber, you can view available interactive solutions manuals for each of your classes for one low monthly price.
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[PC Krause] Analysis of Electric Machinery and Drive Systems
The HMI package for a SCADA system typically includes a drawing program that the operators or system maintenance personnel use to change the way these points are represented in the interface. These representations can be as simple as an on-screen traffic light, which represents the state of an actual traffic light in the field, or as complex as a multi-projector display representing the position of all of the elevators in a skyscraper or all of the trains on a railway.
A "historian", is a software service within the HMI which accumulates time-stamped data, events, and alarms in a database which can be queried or used to populate graphic trends in the HMI.
The historian is a client that requests data from a data acquisition server. The system monitors whether certain alarm conditions are satisfied, to determine when an alarm event has occurred.
Once an alarm event has been detected, one or more actions are taken such as the activation of one or more alarm indicators, and perhaps the generation of email or text messages so that management or remote SCADA operators are informed.
In many cases, a SCADA operator may have to acknowledge the alarm event; this may deactivate some alarm indicators, whereas other indicators remain active until the alarm conditions are cleared.
Alarm conditions can be explicit—for example, an alarm point is a digital status point that has either the value NORMAL or ALARM that is calculated by a formula based on the values in other analogue and digital points—or implicit: the SCADA system might automatically monitor whether the value in an analogue point lies outside high and low- limit values associated with that point.
Examples of alarm indicators include a siren, a pop-up box on a screen, or a coloured or flashing area on a screen that might act in a similar way to the "fuel tank empty" light in a car ; in each case, the role of the alarm indicator is to draw the operator's attention to the part of the system 'in alarm' so that appropriate action can be taken. They employ standardized control programming languages such as under, IEC a suite of 5 programming languages including function block, ladder, structured text, sequence function charts and instruction list , is frequently used to create programs which run on these RTUs and PLCs.
A programmable automation controller PAC is a compact controller that combines the features and capabilities of a PC-based control system with that of a typical PLC. By converting and sending these electrical signals out to equipment the RTU can control equipment, such as opening or closing a switch or a valve, or setting the speed of a pump.
Some users want SCADA data to travel over their pre-established corporate networks or to share the network with other applications.
The legacy of the early low-bandwidth protocols remains, though. SCADA protocols are designed to be very compact. Many are designed to send information only when the master station polls the RTU. These communication protocols, with the exception of Modbus Modbus has been made open by Schneider Electric , are all SCADA-vendor specific but are widely adopted and used.
This has the key advantages that the infrastructure can be self-contained not using circuits from the public telephone system , can have built-in encryption, and can be engineered to the availability and reliability required by the SCADA system operator.
Earlier experiences using consumer-grade VSAT were poor. The result is that developers and their management created a multitude of control protocols. Among the larger vendors, there was also the incentive to create their own protocol to "lock in" their customer base.Author: Paul C.
Extending the material presented in this chapter to the analysis of ac machines is straightforward involving a minimum of trigonometric manipulations. Now customize the name of a clipboard to store your clips.
Analysis of Electric Machinery and Drive Systems
It is without doubt the workhorse of the electric power industry. Deepak Kumar Dash. Paul C.
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