Electrical Machines
Questions & Answers
Question 1: Historical context and background Describe the historical background of the application (timeline, first prototype, development...) Identify at least two of the most common topologies of the electric drive used for your vehicle. Include diagrams Name the main parts of one of the electric drive topologies and describe their function • What is the most common electrical machine used in your vehicle? Why? Include diagrams State the technical specifications of your vehicle (weight, number of passengers...) This section should be less than 3 pages
3.15. The three-phase power and line-line ratings of the electric power system shown in Figure 3.34 are given below. (a) Draw an impedance diagram showing all impedances in per-unit on a 100-MVA base. Choose 20 kV as the voltage base for generator. (b) The motor is drawing 45 MVA, 0.80 power factor lagging at a line-to-line terminal voltage of 18 kV. Determine the terminal voltage and the internal emf of the generator in per-unit and in kV.
To protect a house from electrical hazards, all household circuits should have a household electrical protecting circuit: mention one of them and explain how does it work?
Three single phase transformers are used to form a three phase transformer bank \text { - } 138 \mathrm{kV}(\Lambda) / 120 \mathrm{kV}(\mathrm{Y}) Source is a 120kV transmission line. ●Load side is a 12 MVA load at 0.8 Lagging PF. a. Turns ratio of each transformer. b. Line current at the 120 kV side.
Discuss the measures to mitigate EV load impacts by upgrading the distribution system infrastructure.
) Explain how induction motors' speed can be controlled by frequency (for the below rated speed and above rated speed), include a sketch of the circuit configuration. The results of the no load and blocked rotor parameter tests on a 400 kW, 3300 V, three phase, 4 pole, 50 Hz, Y connected, squirrel cage induction motor is shown below: i. Calculate the no load core loss? ii. Calculate the equivalent circuit parameters in Ohms including R₁, R2, X₁ and X2 Assume that X₁ = X₂. iii.Provide a diagram of a single-phase equivalent circuit for this induction motor(referring to stator side), labelling the components clearly and indicated the supply voltage correctly. Considering the same induction motor as Q( 4b) and presuming the motor is operating at rated voltage and frequency, with a slip of 2.8 % and stator current value of l₁ = 68.01<-15.93° A, calculate the following parameters: i. Motor's Power factor? ii. Input power? iii. Stator losses?
The impedance of the main and auxiliary windings of a 240V, 60HZ,capacitor-start motor are given as: Zm= (5.5+j4.5) ohms and Za= (8.5+j4.2) . ohms Determine the value of the starting capacitance that will cause the main and auxiliary winding currents to be in quadrature at starting. Draw the Schematic and phasor diagram.
Justify your answer for the following questions: DC motors use permanent magnets to construct a static magnetic field. If a motor consumes 184 kW of power but only produces 231 HP at the shaft, itscurrent operating efficiency isanswer to the nearest one.% (1 Horsepower = 745.7 Watts). Round your c) Induction motors use commutators to transmit current to the rotor, thus producing a rotor magnetic field. A live reading of a motor indicates that it is consuming 16.4 kVA with a Power Factorof 0.76. You also know the current operating efficiency of the motor is 89%. What is theinstantaneous power output of the motor? (1 Horsepower = 745.7 Watts).%3D
Why would you prefer to place the field winding on the rotor of synchronous machine?Answer in not more than 2 sentence.
