DE5404 – Electrical Machines
Module code
DE5404
Module title
Electrical Machines
Prescription
To develop understanding of the theory and application of single and three phase electrical machines
Programmes
- EN1603
- SC1101
- WB3535
NZQA Level
Level 5
NZQA Credits
15
Delivery method
- Not Web enabled
Learning hours
- Total learning hours
- 150
Resources required
- Learning Outcomes
- 1.Demonstrate and apply knowledge of transformer theory (single and three phase to 11kV, & vector groups).
2.Demonstrate knowledge of DC motor and generator operation with appropriate speed control systems.
3.Demonstrate knowledge of and apply the theory of AC SQIM and WRIM induction motors.
4.Demonstrate knowledge of AC motor speed control (DOL, star-delta, Primary resistance, autotransformer, soft-starter, VFD/VSD).
5.Demonstrate knowledge of mechanical gearboxes, toothed and V belt systems as may be applied to reduce the speed of an electric motor.
6.Demonstrate knowledge of AC motor selection for typical applications.
7.Demonstrate knowledge of operating an induction synchronous motor as a generator.
8.Demonstrate knowledge of typical single phase AC and fractional horsepower motors (capacitor start and run, split phase, shaded pole, servo and stepper).
9.Demonstrate knowledge of single phase AC speed control systems. - Content
- Single loop conductor in a constant two-pole magnetic field as a motor; direction of rotation; factors influencing torque; shunt wound motor; series wound motor; cumulatively compounded motor; output calculations
Single loop conductor in a constant two-pole magnetic field, direction of rotation; the shunt generator; output calculations
Primary, secondary, turns ratio, kVA rating, equivalent circuit, operation on no-load and full-load, regulation, step up, step down, isolating, autotransformers
Magnetising current, core losses, copper loss, hysteresis losses, the narrow hysteresis loop, explanation of eddy current generation, and the purpose of laminations
Three-phase transformer configurations are explained
Electrical and mechanical power, torque, slip, efficiency, power factor; speed control using pole switching, slip ring motor, and variable frequency drives; testing, analysis and prediction of motor performance using transformer equivalent circuit model; induction machine as a generator (wind or hydro) running on the grid or stand alone
Induction motor starting and protection methods using traditional and solid state starters are described and compared
AC motors for given applications are selected and described. Single-phase induction motors, split-phase, capacitor start, capacitor run, shaded pole and small synchronous; universal motor, stepper motor
Generator; operation on, and synchronisation with an infinite bus; motor starting methods, operating at variable power factors, as a synchronous capacitor start
Synchronous impedance, stability, and operational charts are explained
Calculations using the equivalent circuit of the three-phase synchronous machine
Motors or generators are selected for given applications and the selection justified in accordance with industry practice
Pumps, compressors, fans, high inertia loads, conveyors, winding machines, hydro generation, wind generation, thermal generation, gas turbine generation - Assessment Criteria
- Assignments, Tests30
Laboratory (Practical)20
Examination50
