a four pole 60-Hz, 440-V three phase induction motor is supplied by a variable voltage variable frequency source. the motor has negible stator resistance and a rotor resistance of 0.1 ohm. the total inductance is 2 x 10 ^-3 H. a)find lowest possible frequency and voltage of proper operation. b) determine the starting torque, the speed at maximum torque, and the router's applied voltage when supply frequency is 8 hz, 40 hz and 60 hz
A three phase, 60 Hz induction motor rated at 440 V and 40 hp drives a load at 1710 rpm. The induction motor has the following impedances referred to the stator in /phase: R,=0.1512, X,=0.7512; R2=1.222,X=0.7522; X=25 12 . The core loss is 450 W and friction and windage loss is 250 W. Calculate the following 1. line current and power factor 2. Real and reactive input power 3. Air-gap power 4. Mechanical power and torque developed 5. shaft horse...
A. A three-phase ac induction motor drives a mechanical load. The motor's terminal voltage is 470V, 60 Hz. The motor's line current is 175 A, and the power factor is 0.85 lagging The motor's output power is 140 hp and the motor rotates at a speed of 1735 rpm. The motor's copper and core losses total 8.5 kW combined 1. Determine the number of poles of this motor 2. Determine the motor's shaft torque (N-m). 3. Determine the motor's rotational...
1. Variable frequency electronic generation of sinusoids first requires the grid AC to be rectified into DC. Next the DC is converted to high f AC by an inverter circuit. The entire twostep process is at 95% efficiency. Below you are required to refresh your understanding of AC to DC rectifiers for both single and three phase AC. Diode rectifiers are non-linear loads so grid power factor and harmonic generation are considerations. The total power factor is composed of two...
Three-phase induction motor The three-phase induction motor nameplate gives the following information: 100 HP, 6 poles, 600 V, 60 Hz, PF =0.87. Rated motor slip s=0.0275 and rated motor current is 91.7 A. Measured at rated speed friction and ventilation losses are 1100 W. Measured between two motor terminals resistance is 0.305 Ω. f) For a load such where the motor rotates at the speed of 1180 r / min, determine shaft torque and calculate the mechanical power in HP,...
THREE PHASE INDUCTION MOTOR Explain the effects of the capacitors on the values of the line current and the PF.
The three-phase average power of a synchronous motor is 23kW. The three-phase line supplying the motor has a line voltage rating of 208 V (rms). The line current is 75A per phase. Determine the power factor and the reactive power absorbed by the motor/
A separately excited DC motor is fed from a variable DC source and it drives a variable mechanical load as shown in Figure Q4b. The excitation current If is held constant during the motor operation. (i) How can the motor direction be reversed? (4 marks) (ii) Explain what will happen to the current Ia, the internal voltage Eg, and speed if the mechanical torque increases whilst the DC input voltage VT is held constant. (4 marks) (iii)Explain what will happen...
• Curse exLDUUR. 3. (15 points) A three phase 440V line-to-line source drives a 15 horsepower (1 hp = 746 W) motor at 90% efficiency and 80% power factor lagging. The 15 horsepower figure is the output mechanical power a. Find the current drawn by the motor b. Find the real and reactive power drawn by the motor.
Explain how the switched reluctance motor (SRM) works. Draw the drive circuit for a three phase 12/8 SRM and explain the working states for one phase. Explain the operation of a current controlled SRM drive and propose a design for a suitable control system.