4-25- six pole. Three phase. 40-hp, 60-Hz induction motor has an input when loaded of 35 kw, 51A , 440V And a speed of 1152 rpm ,when uncoupled from the load .the readn are found to be 440-V ,21.3 A ,2.3 KW , and 1199 rpm,the resistance.... Between terminal for the stator winding is 0.25 2 for a Y-connection, the stator core losses and the rotational losse are.determine: a-the power factor b-the horspower

4-25- six pole. Three phase. 40-hp, 60-Hz induction motor has an input when loaded of 35 kw, 51A , 440V And a speed of 1152 rpm ,when uncoupled from the load .the readn are found to be 440-V ,21.3 A ,2.3 KW , and 1199 rpm,the resistance.... Between terminal for the stator winding is 0.25 2 for a Y-connection, the stator core losses and the rotational losse are.determine: a-the power factor b-the horspower

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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17. A single-phase, 120 V, 60 Hz, four-pole, split-phase induction motor gave the following blockedrotor test data:VIP Main winding 32 4 80Auxiliary winding 40 4 128a) Determine the standstill impedances of the main and auxiliary windings.b) Determine the values of the resistances to be added in series with the auxiliary winding to obtain maximum starting torque.c) Compare the starting torques and starting currents with and without the added resistance in the auxiliary winding circuit if the motor is connected to a 120 V, 60 Hz supply
e specifications of a Y-connected three phase induction motor are as follows: 12-hp, 400-V, 17-A, 0.85-PF, 50-Hz, 1410-rpm, S1, Class E, IP22.(a) How many poles does this motor have?(b) Determine the rated torque and rated efficiency of the motor?
The equivalent circuit parameters of a 230-V, 1-phase, 6-pole, 60-Hz induction motor are: R1 = R2’ =10ohm, X1 = X2’ = 10ohm, and Xm = 100ohm. At a slip of 5%, calculate the developed torque and The input power to the motor at 230V, while running on no-load, is 31.4 W at 1.2 A. What is the approximate efficiency of the motor at 5% slip?
A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the following equivalent-circuit parameters at normal frequency:R1.2 ohm, R'2=0.18 ohm, X1= x'2=0.58 ohm, all per phase values. The machine is subjected in service to an occasional fall of 40% in both voltage and frequency. What total mechanical load torque is it safe to drive so that the machine just does not stall under these conditions? When operating at normal voltage and frequency, calculate the speed when delivering this torque and the power developed. Calculate also the speed at which maximum torque occurs. If V and f were both halved, what would be the increase in starting torque from the normal direct-on-line start at rated voltage and frequency? If now the machine is run up to speed from a variable-voltage, variable-frequency supply, calculate the required terminal voltage and frequency to give the 'safe' torque calculated above: (i) at starting, (ii) at 500 rev/min. Repeat (d) for the machine to develop a…
A 3300-V, 50-Hz, 3-phase, 4-pole, star-connected induction motor has identical primary and referred secondary impedances of value 3 + j9 ohm per phase. The turns-ratio per phase is 3/I (stator/rotor), and the rotor winding is connected in delta and brought out to slip rings. Calculate: the full-load torque at rated slip of 5%; the maximum torque at normal voltage and frequency; the supply voltage reduction which can be withstood without the motor stalling; the maximum torque if the supply voltage and frequency both fall to half normal value; the increase in rotor-circuit resistance which, at normal voltage and frequency, will permit maximum torque to be developed at starting. Express this: as a fraction of normal R2and as (3) ohmic values to be placed in series with each of the slip-ring terminals and star connected.
A 208-V, three-phase, Y-connected, synchronous motor takes 7.2 kW at0.8 pf leading. The synchronous reactance of the motor is 4 fl/phase andthe armature-winding resistance is negligible. If the field excitation is adjustedto decrease the excitation voltage by 50% while the load on the motorremains the same, determine (a) the new torque angle, (b) the armaturecurrent, and (c) the power factor.
Three phase 460 hp,415v,4pole,50hz induction motor is operating at Over voltage of 480v and reduced load of 80% of the rated value and draws a line current of 624.06A.The losses at these operating conditions are as follows .The stator conductor loss is 12.6 kw sketch the power flow diagram ,enter the known values and determine (a) rotor speed,(b) shaft output torque ,(c)developed mechanical torque in Nm (d)input power to the stator (f)The input power factor
21. A) At what percentage of slip is the pull-out or breakdown torque of a typical 3-phase squirrel-cage induction motor reached? a) 3% slip b) 10% slip c) 20% slip d) none of the above B) If load is increased beyond the breakdown torque, what happens to the speed of the motor? a) it stops b) it may speed up beyond its rated rpm c) its speed will not change, but its current will go downd) none of the above
A three-phase, 60-Hz induction motor runs at 890 r/min at no load and at 840 r/min at full load. (a) How many poles does this motor have? (b) What is the slip at rated load? (c) What is the speed at one-quarter of the rated load? (d) What is the rotor’s electrical frequency at one-quarter of the rated load?
A 3-phase, 6-pole induction motor is rated 400Hz, 150V, 10hp, 3% slip at rated power output. The windage and friction loss is 200W at rated speed. With the motor operating at rated voltage, frequency, slip, and power output, determine the output torque.
A 208-V, three-phase, Y-connected, synchronous motor takes 7.2 kW at0.8 pf leading. The synchronous reactance of the motor is 4 ohms /phase andthe armature-winding resistance is negligible. If the field excitation is adjustedto decrease the excitation voltage by 50% while the load on the motorremains the same, determine (a) the new torque angle, (b) the armaturecurrent, and (c) the power factor.
The no-load speed of an induction motor is 1914 rpm, the specification shows that it is operated 3-phase, 60 hertz, 1758 rpm and supplied by 425 V. what is the percent speed regulation?