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Chapter 14 Mechanical Systems
Published in Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo, Electrical Power Systems Technology, 2021
Dale R. Patrick, Stephen W. Fardo, Brian W. Fardo
Going back to the split-phase motor of Figure 14.17, we can see that the purpose of the two sets of windings is to establish a simulated two-phase condition in order to start the motor. The single-phase voltage applied to this motor is said to be “split” into a two-phase current. A rotating or revolving magnetic field is created by phase splitting. The start winding of the split-phase motor is made of relatively few turns of small-diameter wire, giving it a high resistance and a low inductance. The run winding is wound with many turns of large-diameter wire, causing it to have a lower resistance and a higher inductance. We know that inductance in an AC circuit causes the current to lag the applied AC voltage. The more the inductance present, the greater is the lag in current.
Mechanical Systems
Published in Stephen W. Fardo, Dale R. Patrick, Electrical Power Systems Technology, 2020
Stephen W. Fardo, Dale R. Patrick
Going back to the split-phase motor of Figure 14-17, we can see that the purpose of the two sets of windings is to establish a simulated two-phase condition, in order to start the motor. The single-phase voltage applied to this motor is said to be “split” into a two-phase current. A rotating or revolving magnetic field is created by phase splitting. The start winding of the split-phase motor is made of relatively few turns of small diameter wire, giving it a high resistance and a low inductance. The run winding is wound with many turns of large diameter wire, causing it to have a lower resistance and a higher inductance. We know that inductance in an AC circuit causes the current to lag the applied AC voltage. The more inductance present, the greater is the lag in current.
Magnetic flux
Published in William Bolton, Engineering Science, 2020
The effect of inductance on the current in a circuit is that, when the applied voltage is switched on or off, the current does not immediately rise to its maximum value or fall to zero but takes some time. When the voltage is switched on and the current starts to increase from zero, then the changing current results in an induced EMF. This is in such a direction as to oppose the growing current (Lenz’s law) and slow its growth. For this reason, the induced EMF is often referred to as a back EMF (Figure 14.14). When the voltage is switched off, then the current starts to fall and so produces an induced EMF. This is in such a direction as to oppose the current falling (Lenz’s law) and so the current takes longer to fall to zero.ExampleWhat is the average back EMF induced in a coil of inductance 500 mH when the current through it is increased from 1.0 A to 3.0 A in 0.05 s? e=LdIdt=0.500×(3.0−1.0)0.05=20V
Effect of coil design parameters on performance of electromagnetic forming process
Published in Materials and Manufacturing Processes, 2022
Manoj Soni, Meraj Ahmed, Sanjay Kumar Panthi, Surendra Kumar
Inductance and resistance of coil depends on its design parameters such as thickness and number of turns, contact angle, inner radius, outer radius and connecting angle. Variation in inductance, resistance and Q-factor can effect the frequency and magnitude of discharge current and losses of the process. Several researchers proposed empirical relation to calculate the inductance, resistance, and Q-factor. Isometric view and actual picture of intermediate and end turn of coil are shown in Fig. 7 (a–d). Parameters related to the coil design such as inner radius (r1), outer radius (r2), thickness of turn (), cut angle (), contact angle (), and connecting angle () are shown in Fig. 7 (a and c). The effective number of turns (η) of bitter coil is different from nominal/total number of turns (N) because of contact () and connecting angle () as given in Fig. 7.
Fault Ride-Through Capability with Mutual Inductance in Low-Voltage Single-Phase Microgrid
Published in IETE Journal of Research, 2022
The mutual inductance is a circuit parameter between two magnetically coupled coils (inductors). Suppose that we have coil 1 with turns and coil 2 with turns. Coil 1 has a current which produces a magnetic flux going through one turn of coil 2. If changes, then the flux changes and an emf (potential difference) is induced in coil 2 which is given by The flux through coil 2 is proportional to the current in coil 1 where . Taking the time derivative of this, then Applying the same procedure starting with coil 2 would end up with a similar equation with an . However, the two mutual inductances are the same such that because the mutual inductance is a geometrical property of the arrangement of the two coils. Thus, the induced emf or potential difference can be given as This induced emf or potential difference has the following features: It opposes the magnetic flux change.It increases if the current changes very fast.It depends on which depends only on the geometry of the two coils rather than the current.
A Method for Determining Nonlinear Inductances of Electrical Equivalent Circuit for Three-Phase Induction Motor
Published in Electric Power Components and Systems, 2018
Mohammed Nasir Ansari, Ankit Dalal, Praveen Kumar
The self-inductance of any phase is the inductance associated with its own current. Considering smooth air-gap, the stator and rotor per-phase self-inductances Ls and Lr, respectively, are independent of the rotor position.