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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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Flux in the rotor core section ∅𝒄 =
ϕm
ϕm
ϕm
None of these
ϕm
In an induction motor, the magnetic flux ϕm established by the stator revolving magnetic field cuts the rotor conductors. At standstill, the entire flux ϕm links the rotor core section, making the rotor core flux ϕc=ϕm.
In an induction motor, the magnetic flux ϕm established by the stator revolving magnetic field cuts the rotor conductors. At standstill, the entire flux ϕm links the rotor core section, making the rotor core flux ϕc=ϕm.
ϕc=ϕm — The rotor core flux is equal to the mutual air-gap flux.
ϕc=2ϕm — (Only in cases where the flux splits between two parallel magnetic paths in the rotor).
The stator produces a rotating magnetic field of flux ϕm which revolves at synchronous speed. This flux path is completed through the stator core, air gap, and the rotor core. Since the rotor core acts as the path for the flux reaching the inner circumference of the stator, it carries the same mutual flux ϕm as the stator core.
The magnetic circuit of an induction motor consists of stator core, air gap, and rotor core.
The rotor core carries the flux that passes through the stator teeth and air gap.
The magnetic flux density in the rotor core is determined by the cross-sectional area and the flux ϕm.
Ensures uniform torque production.
Provides low reluctance path for magnetic flux.
Subject to eddy current losses.
Requires high permeability core material to minimize excitation current.
Polyphase induction motor core design.
Synchronous machine rotor core calculations.
In some large machines, the magnetic circuit is designed such that the flux splits into two, meaning the core flux density is calculated based on ϕm/2. However, for general induction motor theory, the total flux is considered ϕm.
Option B and C are identical to A in the provided prompt, which typically suggests the question focus is simply identifying the relationship between rotor flux and mutual flux.
A is correct — The rotor core flux ϕc is equal to the mutual flux ϕm produced by the stator.
Always verify if the machine design implies a split flux path (common in large machines) or a single path, as ϕcore=ϕm/2 might be required in specific professional exams.