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Examoogle • User • info@examoogle.com • EE-2024-8821
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For a synchronous motor, Curev A & Curve B representing ___________ & _________ respectively.
A) Lagging & Leading PF
B) Leading & Lagging PF
C) Lagging & Unity PF
D) Lagging & Lagging PF
Lagging & Leading PF
Curve A represents the condition of the synchronous motor at lagging power factor (PF), while Curve B represents it at leading power factor. This illustrates how the motor behaves under different load conditions.
Curve A represents the condition of the synchronous motor at lagging power factor (PF), while Curve B represents it at leading power factor. This illustrates how the motor behaves under different load conditions.
P=VIcosϕ — Active Power in an AC circuit
Q=VIsinϕ — Reactive Power in an AC circuit
Synchronous motors can operate at leading, lagging, or unity power factors depending on their excitation. At lagging PF, the motor draws reactive power, while at leading PF, it supplies reactive power to the system, leading to different slip and torque characteristics.
Synchronous motors can maintain constant speed under various load conditions.
The power factor affects the overall efficiency of synchronous motors.
Can operate at any power factor by adjusting excitation.
Higher efficiency compared to induction motors under similar loads.
Requires a separate DC source for excitation.
Complex control systems needed for stability in certain applications.
Used in industrial applications requiring constant speed.
Common in synchronous condensers for power factor correction.
Standard synchronous motors operate at rated frequency and constant speed.
Option B is incorrect as it suggests leading and lagging PF are not represented accurately.
A is correct — it correctly identifies Curve A as lagging PF and Curve B as leading PF.
Understanding the power factor is crucial for optimizing motor performance in various applications.