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) when Rs is negligible.

c) Draw a graph of torque–speed characteristics with volts/hertz control with the range of β between 0.4 and 1.

Solutions

Expert Solution

Before solving relevant equations regarding the equivalent circuit of a induction motor is given below

moving on to answers

hope this helps....reference made from theory and performance of electrical machines by JB Gupta

Manojponduru answered 1 month ago

Next > < Previous

Related Solutions

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;...

A Y- connected, 460- V, 1710- rpm, 60- Hz, 4- pole squirrel cage induction motor has...

A Y- connected, 460- V, 1710- rpm, 60- Hz, 4- pole squirrel cage induction motor has a rotor current at starting 6 times the rotor current at full load. Calculate: a. The starting torque as percent of full load torque. b. The slip and speed at which the motor develops maximum torque. c. The maximum torque developed b the motor as percent of its full load value.

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 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...

A three phase 30 hp 460 volt 60 hz, 1770 rpm design B induction motor with...

A three phase 30 hp 460 volt 60 hz, 1770 rpm design B induction motor with class F insulation and service factor of 1.0 is operating at rated shaft load in a 40 degree C environment and has an expected 20 yr life. A maintenance check shows line to line voltages to be 449.2 V, 431.3 V and 462.4 volts. The percent unbalanced voltage for this motor is: the expected temperature rise equals? The expected insulation life equals? the rerating...

A 60-Hz, 208-V, 2 pole wye connected induction motor is rated at 15hp. The equivalent parameters...

A 60-Hz, 208-V, 2 pole wye connected induction motor is rated at 15hp. The equivalent parameters are as follows: RS = 0.2 Ω RR’ = 0.120 Ω XS = XR’ = 0.41 Ω Xm = 15 Ω The machine has negligible miscellaneous losses but experiences mechanical loss and core loss of 250 W and 180 W, respectively. For a slip of 5 %, determine a) The line current. (44.8  -25.5  A) b) The stator copper losses (1.205 kW)...

A 3-phase, 380 V, 50 Hz , 6 pole, Y-connected induction motor has R1 = 0.1...

A 3-phase, 380 V, 50 Hz , 6 pole, Y-connected induction motor has R1 = 0.1 W , X1 = 0.4 W, R2’ = 0.12 W , X2’ = 0.4 W, Xm = 20 W , Pr = 1 kW. The motor is operated at 970 rpm what is the efficiency?

The parameters of a 3-phase, 4-pole, 50 Hz, Y-connected, wound-rotor induction motor are listed below. These...

The parameters of a 3-phase, 4-pole, 50 Hz, Y-connected, wound-rotor induction motor are listed below. These are the default values of the “Asynchronous Machine” model in MATLAB Simulink. r1=0.5968 ?; r2=0.6258 ?; L1=0.0003495 H; L2=0.005473 H; Lm=0.0354 H; Stator line voltage = 400 V rms. The motor for rotor speeds nm= 0 to 1500 rpm. X1= 0.1097 ohm, X2= 1.719 ohm , Xm= 11.12 ohm, RTH = 0.5853 , XTH = 0.1395 and VTH = 230.82 V. Suppose the motor...

A 440-V, 3-φ 50-Hz, 4 poles, 37.3 kW, Y-connected induction motor has the following parameters: R1=...

A 440-V, 3-φ 50-Hz, 4 poles, 37.3 kW, Y-connected induction motor has the following parameters: R1= 0.1 Ω, X1 = 0.4 Ω , R2′ = 0.15 Ω , X2′ = 0.44 Ω Motor has stator core loss of 1250 W and rotational loss of 1000 W. It draws a no-load line current of 20 A at a p.f. of 0.09 (lag). When motor operates at a slip of 3%, calculate a. input line current and p.f. [57.4@29°A, 0.875 lag] b....

A 50-Hz, 440-V, 2 pole wye connected induction motor is rated at 75 kW. The equivalent...

A 50-Hz, 440-V, 2 pole wye connected induction motor is rated at 75 kW. The equivalent parameters are as follows: RS = 0.075 Ω RR’ = 0.065 Ω XS = XR’ = 0.17 Ω Xm = 7.2 Ω The losses associated with the machine are field and winding, miscellaneous and core loss with values of 1 kW, 150 W and 1.1 kW, respectively. For a slip of 4 %, determine a) The line current. (150.39  -23.08 A) b) The...

Subjects