class: center, middle # EE-362 ELECTROMECHANICAL ENERGY CONVERSION-II # Midterm Recitation ## Ozan Keysan [keysan.me](http://keysan.me) Office: C-113 <span class="meta">•</span> Tel: 210 7586 --- # Synchronous Machines -- ### 6.9 kV(l-l) 50 Hz synchronous motor has a synchronous reactance of 95 \\(\Omega\\)/phase. For this problem all losses and saturation effect may be neglected. -- ## a) Compute the armature current and pf of the motor when supplying 700kW rated power and the load angle is 54.4 degrees. -- ## b) Compute the maximum power this motor can deliver if its field excitation is kept constant at the value in part a. Compute the power factor and armature current. --- ### 6.9 kV(l-l) 50 Hz synchronous motor has a synchronous reactance of 95 \\(\Omega\\)/phase. For this problem all losses and saturation effect may be neglected. ## c) What should be the minimum percentage increase in the field current for the motor to supply 1 MW power. -- ## d) What should be the excitation voltage for the motor to supply rated power while drawing minimum armature current? --- ## Example: -- ## 500 MVA, 3-phase, 4-pole, Y-connected synchronous generator connected to 22 kV infinite bus. -- ## Prime mover power (i.e. mechanical power) is set to 300 MW. -- ### a) Find E and load angle for a power factor of 0.8 lagging. -- ### b) Double check the load angle from the power expression. -- ### c) The field current is changed, and the power factor is adjusted to unity at 300 MW. Calculate the new load angle and the E. --- ## 2019 Final ## Assume a Y-connected salient-pole synchronous machine used in a hydroelectric power plant is connected to a 690 V(line-to-line) infinite bus and rotates at 50 rpm to generate 50 Hz induced voltage. -- ## a) Calculate the number of poles of the generator. --- ## Assume the generator supplies 1.2 MVA at unity power factor. - ## Xq = 0.07 Ω - ## Xd = 0.1 Ω -- ## d) Draw the phasor diagram and label each component. What is the reason of having different Xd, and Xq reactances? Explain and support your reasoning with drawings if necessary. --- ## e) Calculate the required induced voltage Ef magnitude and the load angle (δ) for this operation mode. -- ## f) Calculate the torque for this operation mode. --- ## [Solutions-1](./files/ee362_recitation2.pdf) ## Also uploaded to ODTUClass --- ## You can download this presentation from: [keysan.me/ee362](http://keysan.me/ee362) ---