Designing Electrical Apparatuses

Lectures:
- Design and construction, basic description of the activity, product life cycle, phases of a designer’s work, design methodology.
- Insulation design of equipment, insulation spacing in general, surface paths and air gaps in low-voltage and high-voltage equipment, determination of spark-over distances.
- Supports, insulators, ordinary bushings, bushings with radially and axially controlled potential.
- Current-carrying path, resistance of the conducting path, effect of alternating current, skin effect, proximity effect, effect of ferromagnetic nearby objects.
- Force effects of electric current; influence of the shape and position of the current path; forces acting on wound coils; parallel conductors; special cases of force occurrence; electromagnetic forces in a three-phase system.
- Thermal effects of electric current, permissible temperature rise, steady-state temperature rise, short-term operating, sources of heat in electrical devices, thermal network, its solution.
- Surface cooling, principles of cooling, radiation in free and enclosed spaces, convection in free and enclosed spaces, heat transfer coefficient.
- Contact systems in electrical devices, principles of contact designing, contact materials, contact resistance, constriction resistance, film resistance on contacts.
- Design of arc extinguishers, arc extinguishers for ac current, the principle of operation of a ferromagnetic arc chamber, arc extinguishers for dc circuit breakers, arc-extinguishing coil, the effect of the ferromagnetic side walls of a ceramic arc chamber on electric arc movement.
- Principles of design for vacuum circuit breaker extinguishers; explanation of the principles of radial and axial magnetic fields. Electrical strength under low pressure; heat dissipation from the vacuum extinguishing chamber.

Exercises:
Exercise schedule, credit requirements, course study materials, project assignments

Projects:
1. Design of a bushing with axially controlled potential.
2. Analysis of force effects on the arm of a high-voltage disconnector.
3. Thermal design of electrical apparatuses.
4. Testing, verification, and completion of the project.