Sheets of Electrical Machine 3 (Three-Phase Induction Motors) PDF

Preview

Summary

Electrical Power and Machines Dept. Electric Machines (3) 2011 – 2012 Tanta university Faculty of Engineering Sheet No (4) 1. A 440V , three phase , 50Hz, 6 poles, 945 rpm delta connected induction motor has the following parameters referred to the stator: R1=2Ω, R2=2Ω, X1=3Ω , X2=4Ω When driving a ...

Description

Accelerat ing t he world's research.

Sheets of Electrical Machine 3 (Three-Phase Induction Motors) Sherif M Dabour

Related papers

Download a PDF Pack of t he best relat ed papers 

EMD-QBANK-2014-15 MANJUNAT H K

EE6601-SOLID STAT E DRIVES 2 Marks and 16 Marks-Quest ion Bank Sampat h Kaliavarat han EE2352-SOLID STAT E DRIVES 2 Marks and 16 Marks-Quest ion Bank UNIT-I DRIVE CHARACT ERIST ICS … Sampat h Kaliavarat han

Tanta university

Electrical Power and Machines Dept. Electric Machines (3) 2011 – 2012 Faculty of Engineering

Sheet No (4) 1. A 440V , three phase , 50Hz, 6 poles, 945 rpm delta connected induction motor has the following parameters referred to the stator: R1=2Ω, R2=2Ω, X1=3Ω , X2=4Ω When driving a fan load at rated voltage it run at rated speed. The motor speed is controlled by stator voltage control. Determine the motor terminal voltage, current and torque at 800 rpm. 2. A 2.8 kW, 400 V, 50Hz, 4 poles,1370 rpm star connected induction motor has the following parameters referred to the stator: R1=1.9Ω, R2=4.757Ω, X1=X2=3Ω Load characteristics are matched with motor such that the motor runs at 1370 rpm with full load voltage across its terminals. The motor is controlled by terminal voltage control and load torque is proportional to speed. Calculate the motor terminal voltage and current at half the rated speed. Can the motor be allowed to run continuously at this speed? 3. A 10kW, 400 V, 50Hz, 6 poles, 960 rpm star connected, slip ring induction motor has the following parameters referred to the stator: R1=0.4 , R2=0.6 , X1=X2=1.4 ohm when driving a fan load at rated voltage it run at rated speed. The stator to rotor turns ratio is 2. What resistance must be connected in each phase of the rotor circuit to reduce the speed to 800 rpm? 4. In problem 3 calculate the starting torque and current with and without the added rotor resistance. Comment on the results 5. A three phase, delta connected, 6 pole, 50 Hz, 400 V, 925 rpm, squirrelcage induction motor has the following parameters: R1=0.2Ω, R2=0.3Ω, X1=0.5Ω, X2=1Ω The motor is fed from a voltage source inverter with constant V/f ratio. Calculate i.The motor torque at 30 Hz and a slip speed of 60 rpm. ii.The torque at rated motor current and 75 Hz as a ratio of rated full load torque of the motor...