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Electrical Machines 2

by Senthil
Type: PracticalSpecialization: Electrical and Electronics EngineeringOffline Downloads: 26Views: 1442Uploaded: 9 months agoAdd to Favourite

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Senthil
Senthil
Dr.NGPIT, CBE-48 Department of EEE ELECTRICAL MACHINES-II MANUAL Sub. Code:EE2305 Lab Name: ELECTRICAL MACHINES-II Prepared by: R.Santhiya-AP/EEE 1
Dr.NGPIT, CBE-48 Department of EEE CIRCUIT DIAGRAM (0-10)A MI SPECIFICATIONS RATED POWER MOTOR GENERATOR RATED ARMATURE CURRENT RATED FIELD CURRENT RATED VOLTAGE RATED SPEED Fig:1 REGULATION OF THREE PHASE ALTERNATOR BY EMF AND MMF METHOD Sub. Code:EE2305 Lab Name: ELECTRICAL MACHINES-II Prepared by: R.Santhiya-AP/EEE 2
Dr.NGPIT, CBE-48 Ex.No.:1 Date: Department of EEE REGULATION OF 3–PHASE ALTERNATOR BY EMF AND MMF METHODS AIM: To predetermine the percentage regulation of the given alternator by EMF (Synchronous impedance Method) and MMF (Ampere Turns Method) method, by conducting Open Circuit and Short circuit test. APPARATUS REQUIRED: S.NO. Name of the Apparatus Type Range Quantity 1 Ammeter MC (0 – 2) A 1 2 Ammeter MI (0 – 10) A 1 3 Voltmeter MI (0 – 600) V 1 4 Rheostat Wire wound 350 Ω, 1.2 A 1 5 Rheostat Wire wound 710 Ω, 0.8 A 1 6 Rheostat Wire wound 52 Ω, 5 A 1 7 Tachometer Digital - 1 8 TPST switch - - 1 9 Connecting wires - - As Required PRECAUTIONS:  The motor field rheostat should be kept in the minimum resistance position.  The Alternator field rheostat should be in the position of maximum resistance position.  Initially all switches are in open position. FORMULA: Armature Resistance Ra = 1.6*Rdc in Ω where Rdc=Resistance of dc supply Synchronous Impedance Zs = Eph/IS. Where Eph = open circuit voltage in Volts IS = short circuit current in Amps Synchronous Reactance Xs = √ Zs2 – Ra2 Open circuit voltage for lagging p.f. Eph = √(VphcosΦ + IaRa)2 + (VphsinΦ + IaXs)2 Open circuit voltage for leading p.f. Eph = √(VphcosΦ + IaRa)2 + (VphsinΦ – IaXs)2 Open circuit voltage for unity p.f. Eph = √(Vph+ IaRa)2 + ( IaXs)2 Where Vph = rated short circuit armature current in Amps Percentage regulation = (Eph – Vph)/Vph x 100 Sub. Code:EE2305 Lab Name: ELECTRICAL MACHINES-II Prepared by: R.Santhiya-AP/EEE 3
Dr.NGPIT, CBE-48 Department of EEE TABULATION OPEN CIRCUIT TEST: S.No. Field Current (If)Amps SHORT CIRCUIT TEST: Open Circuit Line Voltage (VoL) Volts Open circuit Phase Voltage (Vph) Volts S.No. EMF Method S.No. Field Current (If) Amps Short Circuit Current (120% to 150% of rated current) (ISC) Amps MMF Method Power factor % Regulation Lag Lead S.No. Power factor % Regulation Lag Lead MODEL GRAPH OPEN AND SHORT CIRCUIT CHARACTERISTICS EMF METHOD Sub. Code:EE2305 MMF METHOD Lab Name: ELECTRICAL MACHINES-II Prepared by: R.Santhiya-AP/EEE 4

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