Question

In: Electrical Engineering

A three-phase motor is delta connected to a 415 V, 60 Hz line. If the line...

A three-phase motor is delta connected to a 415 V, 60 Hz line. If the line current is 25 A and the motor power factor is 0.75, how much power is consumed by the motor (a) Determine the size of the bank of three capacitors to improve the power factor of the motor to 0.95. The capacitors are delta connected. (b) If two of the motors work together, what is the size of capacitors to correct the power factor to 0.95 if delta connected?

Solutions

Expert Solution


Related Solutions

A 3 phase 460 V, 60 Hz, 4 pole, delta connected induction motor has the following...
A 3 phase 460 V, 60 Hz, 4 pole, delta connected induction motor has the following equivalent circuit parameters. Rs = 0.42 Ω, Rr = 0.23 Ω, Xs = Xr = 0.82 Ω. Xm = 22 Ω. The no load loss = 60 W and may be assumed constant. The rotor speed is 1750 rpm. Use the approximate equivalent circuit ( i.e. the Xm branch is at the very left of the circuit) determine the following a. the synchronous speed...
Q5 A 3-phase, 60 Hz, 500 V, delta connected motor develops mechanical output of 250 H.P.,...
Q5 A 3-phase, 60 Hz, 500 V, delta connected motor develops mechanical output of 250 H.P., the power factor being 0·7 lagging (without capacitors) and motor efficiency 88%. A bank of series capacitors is connected in delta across the supply terminals. Two similar capacitors connected in series exist in each phase. Each of these capacitors is rated at 250 V, 800 µF. What is the new power factor of the motor after connecting the capacitor bank, also find out saving...
Tests were carried out on a three-phase 220 V, 50 Hz, 4-pole delta-connected induction motor. The...
Tests were carried out on a three-phase 220 V, 50 Hz, 4-pole delta-connected induction motor. The following results were obtained from open circuit (no-load) and short circuit tests.             Open Circuit (no-load) Test Applied Stator Voltage VLine (V) Stator Line Current ILine (A) Total Input Power Pin (W) 240 9.6 536 220 7.2 420 200 5.4 352 180 4.3 304 160 3.5 276 140 3.0 248 120 2.5 224             Short Circuit (locked rotor) Test Applied Stator Voltage VLine (V) Stator Line...
A balanced three-phase delta-connected source has a line veltage of 120 V. It is connected to...
A balanced three-phase delta-connected source has a line veltage of 120 V. It is connected to a load via a three-wire transmission line. The per-phase impedance of the delta-connected load is 30 + 120j (2. The impedance of each wire of the transmission line is 2 + 4j 2. How much power is dissipated by the load? By the transmission line? What is the power factor of the load? What is the overall power factor?
Q3) A three-phase, Y-connected, 220 V, 13 kW, 60 Hz, six-pole induction motor has the following...
Q3) A three-phase, Y-connected, 220 V, 13 kW, 60 Hz, six-pole induction motor has the following parameter values in Ω/phase referred to the stator: R1 = 0.3 Ω. R2' = 0.15 Ω X1 = 0.5 Ω. X2'= 0.21 Ω Xm = 13.25 Ω The total rotational losses are 450 W. The core loss is lumped in with the rotational losses. For a slip of 0.02, and based on approximate equivalent circuit, determine: (i) The rotor speed. (ii) The stator current....
A balanced positive-sequence wye-connected 60-Hz three-phase source has line-to-line voltages of VL = 440 V rms....
A balanced positive-sequence wye-connected 60-Hz three-phase source has line-to-line voltages of VL = 440 V rms. This source is connected to a balanced wye-connected load. Each phase of the load consists of a 0.5-H inductance in series with a 50-? resistance. Assume that the phase of Van is zero. A) Find the line-to-neutral voltage phasor Van. Enter your answer using polar notation. Express argument in degrees. B) Find the line-to-neutral voltage phasor Vbn. Enter your answer using polar notation. Express...
A   three-phase,   460-V,   60-Hz,   six-pole   Y-connected   induction   motor   has   Rs = 0.32 Ω, R′ r =...
A   three-phase,   460-V,   60-Hz,   six-pole   Y-connected   induction   motor   has   Rs = 0.32 Ω, R′ r = 0.18 Ω, Xs = 1.04 Ω, X′ r = 1.6 Ω,   and   Xm = 18.8 Ω.   The   no-load   loss,   Pno load,   is   negligible.   The   load   torque,   which   is   proportional   to   speed   squared,   is   180 N#m   at   1180   rpm.   If   the   motor   speed   is   850   rpm,   determine   (a)   the   load   torque   demand   TL; (b)   the   rotor   current   I′ r; (c)   the   stator   supply   voltage   Va;...
Three equal impedances, 60 + j30 Ω each, are delta-connected to a 230-V rms, three-phase circuit....
Three equal impedances, 60 + j30 Ω each, are delta-connected to a 230-V rms, three-phase circuit. Another three equal impedances, 40 + j10 Ω each, are wye-connected across the same circuit at the same points. Determine: (a) the line current (b) the total complex power supplied to the two loads (c) the power factor of the two loads combined
A three-phase, 11.2-kW, 1750-rpm, 460-V, 60-Hz, four-pole, Y-connected induction motor has the following parameters: Rs =...
A three-phase, 11.2-kW, 1750-rpm, 460-V, 60-Hz, four-pole, Y-connected induction motor has the following parameters: Rs = 0.53 Ω, R’r = 0.38 Ω, Xs = 1.23 Ω, X’r = 1.45 Ω, and Xm = 25.2 Ω. The motor is controlled by varying both the voltage and frequency. The volts/hertz ratio, which corresponds to the rated voltage and rated frequency, is maintained constant. a) Calculate the maximum torque, Tm and the corresponding speed, ꞷm for 60 Hz and 30 Hz. b) Repeat...
A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of...
A three phase, 60 Hz, 480 V, Y-connected, two-pole synchronous generator has a synchronous reactance of 0.95 Ω per phase. Its armature resistance is negligible. Its combined friction and windage losses are 1.3 kW and its core losses are 0.95 kW. The field current is constant at no-load. Its full load armature current is 55 A at 0.9PF lagging. Assume phase voltage is a reference. Determine following: a) Its terminal voltage when it is loaded with the rated current at...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT