V and Inverted V Curves of Synchronous Machines: Experimental Setup and Analysis

Introduction  The V and Inverted V curves of a synchronous machine illustrate the relationship between armature current and excitation current under constant power conditions. These curves help analyze the machine's power factor and stability. 1. Experimental Setup Equipment Required Synchronous machine (alternator or motor) DC source for field excitation Three-phase power supply Ammeter (for armature and field currents) Voltmeter (to measure line voltage) Wattmeter (to measure power) Rheostat (to vary field excitation) Load (resistive or inductive) Circuit Diagram  2. Procedure V Curve (Armature Current vs. Field Excitation for Constant Load) 1. Set up the synchronous machine with a connected load. 2. Start the machine as an induction motor and apply DC field excitation to achieve synchronization. 3. Adjust the excitation current (If) gradually from under-excited to over-excited conditions. 4. Record the armature current (Ia) at each excitation level while maintaining constan...