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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
operating temperature open systems interconnection (OST) model a framework for organizing networking technology developed by the International Standards Organization (ISO). Generally called the OSI model. open waveguide a type of waveguide whose cross section is not bounded by perfect electric conductor, i.e., a waveguide for which the boundary value problem is on an infinite domain. A few examples are optical fiber, microstrips, coplanar waveguides, dielectric waveguides. open-circuit test a transformer test conducted by applying nominal voltage on the low voltage side while keeping the high voltage side open. By measuring the power in, current, and voltage, the magnetizing reactance of the transformer equivalent circuit can be determined. open-circuit quarter-wave transmission line transmission line of ninety degrees electrical length where one end of the line is terminated in an open-circuit impedance. The properties of the transmission line result in the non-open circuited end to exhibit a short-circuit impedance. open-delta transformer a connection similar to a delta-delta connection, except that one singlephase transformer is removed. It is used to deliver three-phase power using only two single-phase transformers. The normal capacity of the opendelta transformer is reduced to 57.7% of its delta rating. opening for structuring element B, the composition of the erosion by B followed by the dilation by B; it transforms X into X B = (X B) B. The opening by B is what one calls an algebraic opening; this means that: (a) it is a morphological filter; (b) it is anti-extensive, in other words it can only decrease an object. See dilation, erosion, morphological filter, structuring element. open-loop control system a control system in which the system outputs are controlled by the system inputs only, and no account is taken of the actual system output. open-loop gain the gain of an operational amplifier with no feedback applied (with the negative feedback loop "open"). open-loop-feedback control predictive control policy with repetitively used decision mechanism, that at a given time instant, considers current state of the controlled process -- or the current estimate of this state -- and computes the values of the control inputs for the next intervention instant or interval by performing an open-loop optimization of the process operation over specified prediction (optimization) interval. The open-loop optimization can be defined as an open-loop stochastic optimization problem or as a deterministic optimization problem using a single forecast of the free inputs over specified prediction interval; other forms of open-loop optimization problems can also be defined. Model-based-predictive control, widely used as an industrial standard, is usually realized in the form of the open-loopfeedback control. operand specification of a storage location that provides data to or receives data from the operation. operand address the location of an element of data that will be processed by the computer. operand address register the internal CPU register that points to the memory location that contains the data element that will be processed by the computer. operating point See set point.
MATLAB Simulation of Circle Diagram in Three Phase Induction Motor
Published in IETE Journal of Education, 2022
This test is similar to the open circuit test of a transformer. The load is released from the motor, and rated voltage V at rated frequency is applied to the stator. Thus, the slip at this condition is s = 0. The open circuit condition, considering s = 0, can be checked from Figure 1(d). The laboratory circuit arrangement is shown in Figure 2. Here, the input power is measured by the two-wattmeter method [13]. The ammeter measures the no load current, and the voltmeter shows the normal rated supply voltage. The no load current being 20–30% of the full load current, the I2R loss due to this may be neglected. At no load, the total power input is equal to the constant iron loss, friction, and windage loss of the motor.
Teaching Synchronization of Synchronous Generator Using Virtual Laboratory
Published in IETE Journal of Education, 2023
Arif Iqbal, Girish Kumar Singh
With the creation of virtual tests, physical and economic limits in the teaching–learning process are overcome to some extent. A very less literature is available that suggests to incorporate the simulation tools in teaching–learning process of undergraduate electrical machinery courses. In Ref. [4], a method to conduct different tests of a single-phase power transformer was described, which includes open-circuit test, short circuit test, load test, and short-heat run test. Virtual testing (no-load and blocked-rotor test) was investigated on a three-phase induction motor [5], and circle diagram was developed [6]. Concept of web-based virtual laboratory was used to perform experiment on synchronous machine, highlighting a controlled operation in motoring mode, and some tests (no-load test and blocked-rotor test) in generating mode [7]. But an extensive exploration of synchronous machine in an interconnected system, using user-friendly simulation tools for an improved teaching–learning process, has not been reported so far. Therefore, the major contribution of this paper is to teach the synchronization of synchronous generator with running alternator using a virtually developed simulation model on MATLAB/Simulink platform. The concept of virtual laboratory has been further extended to motivate the students for further research work, for which the performance improvement has been shown in synchronization processes of test machine by using a closed loop speed control scheme of prime mover. Implementation of a closed loop control scheme on virtual platform will be certainly beneficial for further learning, particularly for final year students and young researchers.