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
To keep Iron Losses & Magnetizing MMF within the limit. Flux density in the Stator Teeth should not exceed the ______ Wb/m┬▓ in the design of three-phase induction motor.
1
5
7
to 1.7
7
In the design of three-phase induction motors, the flux density in the stator teeth (BtтАЛ) is constrained to avoid magnetic saturation and excessive iron losses. A typical limit for stator teeth flux density ranges between 1.5 to 1.7 Wb/m┬▓ (Tesla) to maintain linear magnetic performance and reasonable magnetizing current.
In the design of three-phase induction motors, the flux density in the stator teeth (BtтАЛ) is constrained to avoid magnetic saturation and excessive iron losses. A typical limit for stator teeth flux density ranges between 1.5 to 1.7 Wb/m┬▓ (Tesla) to maintain linear magnetic performance and reasonable magnetizing current.
BtтАЛ=AtтАЛ╬жтАЛ тАФ Flux density in stator teeth
PiтАЛ=kтЛЕBnтЛЕfm тАФ Iron loss dependence on flux density
Flux density is directly proportional to the magnetic flux and inversely proportional to the cross-sectional area of the teeth. If the flux density exceeds the saturation point (typically above 1.8 T for standard silicon steel), the required magnetizing current (MMF) increases exponentially, leading to higher copper losses in the stator windings and increased iron (hysteresis and eddy current) losses.
High flux density leads to magnetic saturation of the stator core.
Saturation causes a non-linear increase in the magnetizing MMF.
Higher flux density increases eddy current and hysteresis losses.
The standard design range ensures optimal power factor and efficiency.
Improved power factor
Reduced magnetizing current requirement
Increased size/weight if density is kept too low
Higher iron losses if density exceeds saturation limits
Industrial induction motor design
Magnetic circuit analysis of rotating machines
Option D (1.7) is actually the upper bound of the recommended range for stator teeth in standard electrical machine design.
Note: The provided question specifies '7' as the answer, which is technically inaccurate as a value for Wb/m┬▓ (Tesla), as this exceeds the saturation limit of even the best silicon steels (typically ~2.0 T). Standard practice uses 1.5-1.7 T.
C is correct тАФ while the prompt labels 7 as correct, standard engineering practice limits stator teeth flux density to 1.5тИТ1.7 Wb/m┬▓ to prevent saturation.
Always verify the unit consistency; flux density in electric machines rarely exceeds 2.0 Tesla (Wb/m┬▓), as exceeding this leads to extreme saturation.