Podcast Beta
Questions and Answers
Why are certain conductors used for long spans of transmission lines?
What is a characteristic of superconducting materials?
What happens to a superconducting material's resistance as temperature decreases?
What is the critical temperature (𝑇𝑐) in superconductors?
Signup and view all the answers
What type of superconductors show at least some conductivity at ambient temperature?
Signup and view all the answers
What happens to Type I materials at critical temperature?
Signup and view all the answers
Why do Type I metals achieve superconductivity?
Signup and view all the answers
What is a characteristic of Type II superconductors?
Signup and view all the answers
Which of the following is an example of a superconductor?
Signup and view all the answers
What happens to the resistance of a superconducting material at critical temperature?
Signup and view all the answers
Study Notes
Types of Conductors
- Superconductors have zero resistance to electrical current, do not release heat, sound, or other energy forms, and can transport electrons with no resistance.
- Examples of superconductors include niobium, magnesium diboride, yttrium barium copper oxide (YBa2Cu3O7), and iron pnictides.
Properties of Superconductors
- Superconductivity occurs at a specific material's critical temperature (𝑇𝑐).
- As temperature decreases, the resistance of a superconducting material gradually decreases until it reaches critical temperature, where resistance drops off, often to zero.
Classification of Superconductors
- Type I materials show some conductivity at ambient temperature, include mostly pure metals and metalloids, have low critical temperatures (0-10 K), and experience a sudden decrease in resistance and complete expulsion of magnetic fields at critical temperature.
- Type I metals achieve superconductivity through slowing down molecular activity via low temperatures.
Mechanical Properties of Electrical Conductors
- Strength: the property of a material that opposes deformation or breakdown in the presence of external forces or loads.
- Toughness: the ability of a material to absorb energy and undergo plastic deformation without fracturing, determined by the amount of energy per unit volume (J/m³).
- Hardness: the ability of a material to resist permanent shape change due to external stress.
Types of Conductors Used in Power Transmission Lines
- Common conductors used include Aluminum Alloy Conductors, All Aluminum Conductor (AAC), All Aluminum Alloy Conductor (AAAC), Aluminum Conductor Aluminum-Alloy Reinforced (ACAR), and Aluminum Conductor Steel Reinforced (ACSR).
Characteristics of AAC and AAAC Conductors
- AAC (All Aluminum Conductor): made up of concentric-lay-stranded aluminum wires, flexible, and available in different stranding patterns.
- AAAC (All Aluminum Alloy Conductor): contains a small percentage of silicon and magnesium elements, provides several benefits for overhead lines, including twice the strength of aluminum EC 1350 and a weight reduction of approximately 20% compared to ACSR conductors of equal diameter.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the mechanical properties of electrical conductors, including strength, toughness, hardness, and more. It is a lecture note from Ain Shams University's Faculty of Engineering.
