HANSABA COLLAGE OF ENGINEERING & TECHNOLOGY 8th SEM ELCTRICAL SUB:-DAM Design of Synchronous Machine ASSIGNMENT:-1 _______________________________________________________________________ 1. 2. 3. 4.

Derive the output equation of Synchronous machine. Explain SCR and its effect on synchronous machine performance. Define SCR and its importance in designing of synchronous machine. Define SCR of a synchronous machine. Discuss the importance of SCR in the design of synchronous machine. 5. Explain Step of design of filed winding of alternator. 6. Explain importance of damper winding in synchronous machine. 7. Explain evaluation of Direct and Quadrature axis reactance of Alternator. 8. Discuss effect of air gap length on performance of synchronous machine. 9. Explain steps for field winding design in case of a synchronous machine. 10.Discuss algorithm and develop flow chart for main dimension design of a low speed alternator. 11.Write the steps and necessary equations for rotor design of an synchronous machine 12.Give the rules for selecting number of rotor slots in induction motor. 13.Discuss in steps the design of field winding of a salient pole synchronous machine. 14.Discuss the design differences of a salient pole and non-salient pole synchronous machines. 15.Explain hunting in Synchronous machine. Example:1. Determine the main dimensions and Turns per phase (Tph) of a 3000 KVA, 6.6 KV, 50HZ, 187 RPM, 3 phase, star connected alternator. Assume average flux density =0.58 wb/m2 ac=35000.Assume pole arc/pole pitch=0.7. 2. Calculate the diameter, core length, no of conductors of the stator, size of conductor, no of stator slots of 30 MVA, 11KV, 3000RPM, 50 HZ, star connected Turbo alternator. Assume Bav= 0.55 Wb/m2, ac=55000 A/m Kw=0.955, peripheral velocity= 160m/s. 3. Determine main dimensions and turns per phase of a 3 MVA, 11 kV 50 Hz 32 pole three phase star connected alternator. Assume average gap density of 0.55 wb/m2, ac = 30000, winding factor 0.955. Use L/τ ratio of 1.2.

4. A 2500 kVA 32 pole three phase, 60 Hz, 2400 V, star connected salient pole alternator has the following design data: Stator bore = 2.5 m; core length = 0.44m; turns/phase = 224; winding factor =0.95; length of air gap 10 mm; air gap contraction factor = 1.11; ratio of pole arc to pole pitch = 0.69; ratio of amplitude of fundamental of gap flux density to maximum gap density = 1.068; per unit leakage reactance = 0.14. Determine direct and quadrature axis synchronous reactance. 5. A 1250 kVA, 3-phase, 50 Hz, 3300V, 300 r.p.m synchronous generator with a concentric winding has Bav =0.58 Wb /m2, ac= 33000A/m, gap length 5.5mm, field turns per pole =60, short circuit ratio =1.2, The effective gap area is 0.6 times the actual area. Peripheral speed is 30 m/s. Find the stator core length, stator bore, turns per phase, mmf for air gap, armature mmf per pole, and field current for no load and rated voltage. 6. The following is design data available for a 1250 KVA, 3-phase, 50Hz, 3300V, star connected, 300 rpm alternator of salient pole type : Stator bore D=1.9m, stator core length L=0.335m, ratio of pole arc to pole pitch=0.66, turns per phase=150, single layer concentric winding with 5 conductors per slot, short circuit ratio=1.2. Assume that distribution of gap flux is rectangular under the pole arc with zero values in the interpolar region. Calculate (i) specific magnetic loading (ii) air gap length. Mmf required for air gap is 0.88 of no load field mmf and gap contraction factor is 1.15. 7. Determine the main dimensions for a 1000 KVA, 50 Hz, 3 phases, 375 r.p.m. alternators. The average air gap flux density is 0.55 Wb/m2 and the ampere conductors per meter are 28000, winding factor 0.955. Take ratio of core length to pole pitch equals to 2. Check that simple bolted on pole construction can be used, if run away speed is 1.8 times the synchronous speed and the maximum permissible peripheral speed for the bolted on pole construction is 50 m/s. 8. Determine the main dimensions of 20 kW, 3 phases, 400 V 50 Hz, 1450 rpm squirrel cage induction motor. Assume following: Full load efficiency: 85%. Full load power factor: 0.89 lag. Winding factor: 0.955. Specific magnetic loading: 0.45 wb/m2. Specific electrical loading 28000 A/m. Rotor peripheral speed 20 m/sec at synchronous speed. Last Date of Submission:-