Question

What is the formula of the angle between secondary induced voltage and secondary current?

(a) phase angle = tan^-1 *[(reactance of the secondary winding – reactance of the external burden) / (resistance of the secondary winding + resistance of the external burden)]

(b) phase angle = tan^-1 *[(reactance of the secondary winding – reactance of the external burden) / (resistance of the secondary winding – resistance of the external burden)]

(c) phase angle = tan^-1 *[(reactance of the secondary winding * reactance of the external burden) / (resistance of the secondary winding + resistance of the external burden)]

(d) phase angle = tan^-1 *[(reactance of the secondary winding + reactance of the external burden) / (resistance of the secondary winding + resistance of the external burden)]

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I want to ask this question from Errors topic in portion Design of Current Transformers (CT) of Design of Electrical Machines

Answer 1

The correct option is (d) phase angle = tan^-1 *[(reactance of the secondary winding + reactance of the external burden) / (resistance of the secondary winding + resistance of the external burden)]

Easiest explanation: The reactance of the secondary windings and the external burden is first calculated. Next, the resistance of the secondary windings and external burden is calculated and on substitution gives the value of the phase angle.