Eddy current losses - solid/laminated cores

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SUMMARY

The discussion focuses on calculating average eddy-current power losses in solid and laminated magnetic cores subjected to a uniform magnetic field. The solid core has a length L, radius a, and conductivity σ, while the laminated core consists of N filamentary cylinders, also with length L and conductivity σ. Key calculations involve determining the average eddy-current power loss for both core types, utilizing the relationship between current density J and electric field E, where J = σE. The skin depth concept is crucial for accurate calculations, particularly for the solid core.

PREREQUISITES
  • Understanding of electromagnetic theory, specifically eddy currents
  • Familiarity with the concept of skin depth in conductive materials
  • Knowledge of Maxwell's equations, particularly ∇xE = -d(B)/dt
  • Basic proficiency in calculating power losses in electrical systems
NEXT STEPS
  • Study the derivation and application of skin depth in conductive materials
  • Learn how to calculate eddy-current losses in different core configurations
  • Explore the impact of frequency on eddy-current losses in magnetic materials
  • Investigate the use of finite element analysis (FEA) for simulating magnetic fields and losses
USEFUL FOR

Electrical engineers, physics students, and professionals involved in designing magnetic components or optimizing electromagnetic systems will benefit from this discussion.

satchmo05
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Homework Statement


[PLAIN]http://img94.imageshack.us/img94/224/92898534.jpg
The figures show two types of magnetic cores that lie along the z-axis. The solid core has length L, radius a, and conductivity σ. Laminated core has N filametary cylinders each with length L and conductivity σ. If B = Bocosωt az is directed upward and the filamentary cylinders fill 90% volume of solid core, find:
a.) the average eddy-current power loss in the solid core
b.) the average eddy-current power loss in each of the filamentary cores.
c.) the average eddy-current power loss in the total laminated core.

Assume the B-field is uniform throughout both solid and laminated cores.

Homework Equations


This is the problem, I don't know what formulas I should be using!

The Attempt at a Solution


Just an attempt, this is probably way off. It I attempt to find J within the cylinder, than J = σE. I know that ∇xE = -d(B)/dt. This way I can solve E, and plug it into the formula I have started with, giving me J. What would I do from here though!? Is this even the right way?! Please help! I appreciate all help in advance!
 
Last edited by a moderator:
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For the first core, you need to know the skin depth. Have you covered that in class yet?
 
no, we have not.
 

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