Join 60,000+ competitive exam aspirants
or with email
Your Cart
SubtotalтВ╣0
TotalтВ╣0
Examoogle тАв User тАв info@examoogle.com тАв EE-2024-8821
Chapter 1 of 12 тАв Page 1 of 248ЁЯФТ Protected PDF тАв Watermarked
Join 60,000+ competitive exam aspirants
n a synchronous motor, at no-load condition, and with normal excitation the armature current drawn by a synchronous motor is
Zero
Lagging applied voltage
Leading Applied voltage
In phase with applied voltage
Lagging applied voltage
In a synchronous motor at no-load conditions with normal excitation, the armature current is lagging the applied voltage. The correct answer is B.
In a synchronous motor at no-load conditions with normal excitation, the armature current is lagging the applied voltage. The correct answer is B.
P=VIcos╧Х тАФ Power equation for AC circuits.
Q=VIsin╧Х тАФ Reactive power in AC circuits.
This occurs because, at no-load, the synchronous motor operates in a leading power factor region, causing the armature current to provide reactive power necessary for the motor's magnetic field, resulting in it lagging behind the applied voltage.
Synchronous motors operate at a constant speed regardless of the load.
At no-load, they draw a small amount of reactive power.
High efficiency at rated load.
Stable operation under varying loads.
Requires auxiliary starting methods.
More complex control systems needed.
Used in industrial applications for constant speed.
Ideal for driving large pumps and compressors.
Standard values of armature current in synchronous motors are often low at no-load conditions.
Option A is incorrect because the armature current is not zero; Options C and D do not accurately describe the phase relationship.
B is correct тАФ The armature current drawn by a synchronous motor at no-load condition is lagging the applied voltage because of the motor's capacity to provide reactive power.
Understanding the power factor and phase relationships in AC circuits is crucial for mastering synchronous motor concepts.