The equivalent circuit can be solved easily for estimating the performance like terminal voltage across the secondary etc.
Decrease the output of the variacabd repeat the above procedure again.Draw the two theoretical semi-circles.(8.7) shows the circuit diagram, based upon which both the tests can be performed.Switch-on the supply to the circuit.Repeat step 6 for various values of applied voltage to the armature, till the rated voltage of the motor.Switch off all the loads and supply.List the condition to be satisfied for voltage build up of a DC generator.
While making the field current adjustments do not retrace.
Calculation Kn Wa _.
35 P a g e AIM OF THE experiment To find Magnetization characteristic of a separately excited DC generator.9) Draw the internal and external characteristics for a dc zonealarm 6.5 full installer shunt generator.Switch on the ac supply.Since, in this test, the applied voltage is a small percentage of the normal voltage, the mutual flux ø produced is also a small percentage of its normal value.What will happen to the transformer, if a sufficient voltage is applied during the short circuit test?Vary the RL load to obtain different readings of ammeters, and wattmeter.As such, rms values of currents, IR, IY and IB are taken equal in magnitude and lagging by an angle with respect to its own phase voltage, similarly, rms values of phase voltages are also equal in magnitude but displaced by 1200.Add the currents obtained in step (4) and (5) and compare with the currents obtained in step(3), to verify the theorem.Regulation : Regulation of the transformer can now be calculated based on the parameters of the equivalent circuit, using the approximate formula given below.Keep the applied voltage to the armature constant at its rated value.And I3 is the current flowing through load.Vary the voltage applied to the armature by varying the external resistance in the armature circuit.