Secondary winding arrangements

Figure 3-18 Forward-mode secondary winding arrangements (a) center-tapped secondaries (b) full-wave secondaries (c) isolated secondaries.

That would have brought the Drain end of the Primary winding right next to the safety barrier, with the Secondary ground end (which is usually connected to the chassis) directly across the isolation boundary. With this winding arrangement, we would have a healthy dose of CM noise injected directly into the chassis/earth. 

Now let us apply what we have learned to our ongoing numerical example. We start by taking a copper foil wound twice on the ETD-34 bobbin — to form the 5 V secondary winding. Since this is interleaved with respect to the primary, only one turn belongs to each split section. So the layers per portion for the secondary is p = 1. We will calculate the losses, and if acceptable, we will stay with the resulting arrangement. 

Three methods of arranging the windings of three-phase transformers are commonly encountered star, delta and zig-zag. Each method can be applied to either or both of the primary and secondary windings, Figure 6.6 shows the three forms. 

High voltage supphes within a plant are invariably arranged as three-phase star-connected systems. The star point of the transformer secondary winding or the generator stator winding is... 

To examine the phenomena more closely a transformer circuit is shown schematically in Fig. 1. The primary winding is connected through the lumped circuit resistance to a voltage supply. The secondary winding, coupled to the same core, is connected to a lumped secondary circuit resistance and to an inductive load. This simplified transformer and load arrangement is sufficiently general to illustrate the desired principles of operation. The circuit equations for the primary and secondary circuits are as follows ... 

The current transformer is arranged with its primary winding in series with the supply (Figure 17.8). It thus carries the load current. The measuring instrument is connected across the secondary as shown. The ideal theoretical relationship between the currents and the number of turns on the primary and secondary is ... 

Swirl-flow devices include a number of geometric arrangements or tube inserts for forced flow that create rotating and/or secondary flow inlet vortex generators, twisted-tape inserts, and axial-core inserts with a screw-type winding. 

Coiled springs are made by winding wire into a spiral. In this process, the primary structure (electron-sea model, Section 12.8) of the metal remains unchanged. However, the local conformation, or arrangement in space, of the wire has changed. The spiral, or helix, is a regular local conformation that defines the secondary structure of the metal atoms in the spring. 

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