Current transformers circuit diagrams

I2 - Secondary current referred to the primary side Figure 15.17 Equivalent circuit diagram of a current transformer... 

The short-circuit test is conducted by shorting one of the transformer s cods, and applying rated current to the other cod. Only a fraction of the rated voltage is needed to produce the rated current. The input current and power are then measured. Figure 10.10 shows a circuit diagram for this test. 

To investigate the current error (ratio error) and phase displacement for a current transformer, consider the simplified phasor diagram in Fig. 27. It can be seen that the difference in magnitude between the primary current 7p and the secondaiy current multiplied by the rated transformation ratio ihK ) is dependent on the amount of the primary current used to energize the core, which must therefore be kept to a minimum. It should be noted that a CT is operated with a load consisting of an ammeter that almost short-circuits the secondaiy terminals should this... 

The experimenter should construct the circuit of Fig. 10,5 on the next page. At first, the wires shown as dashed lines are not connected. The experiment is done as on page 7 of the first chapter, where the "switch" is opened suddenly, and there is a bright flash in the neon bulb. Then the short circuiting clip lead (dashed line in the diagram) is attached to the transformer s 120 volt coil (heavily insulated black wires or soldered-on power cord). Now when the switch is opened, there is no neon flash. What is happening is that current is induced in the "shorted" coil, as the battery current suddenly decreases. This new current has a magnetic field... 

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