How do the primary current and reactive power change with different inductive loads in theexperiment? Explain the fundamental theory for the change.

The primary current and reactive power in an electrical system change with different inductive loads due to the properties of inductance and the nature of alternating current (AC) systems.

1. Inductive Load and Primary Current: Inductive loads, such as motors and transformers, create a magnetic field when energized. This magnetic field opposes changes in current, causing a delay or "lag" between the voltage and current waveforms in an AC system. This is known as the phase difference. As the inductive load increases, the phase difference also increases, which in turn increases the primary current. This is because the system needs to supply more current to overcome the increased opposition from the larger magnetic field.

2. Inductive Load and Reactive Power: Reactive power is the power that alternates between the source and load in an AC system. It is the result of the phase difference between the voltage and current. In an inductive load, the current lags behind the voltage, resulting in positive reactive power. As the inductive load increases, the phase difference and thus the reactive power also increase.

3. Fundamental Theory: The fundamental theory behind these changes is Faraday's law of electromagnetic induction and the concept of reactance in AC systems. Faraday's law states that a change in the magnetic field within a closed loop of wire induces an electromotive force (EMF) in the wire. In an AC system with an inductive load, the changing current creates a changing magnetic field, which induces an EMF that opposes the current. This is known as inductive reactance, and it increases with both the frequency of the AC system and the inductance of the load. This results in an increase in both the primary current and the reactive power as the inductive load increases.