Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
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Chapter 37, Problem 3SQ
To determine
Choose the correct option that could cause the problem as follows: When the motor is running in second speed. All of a sudden, it accelerates to the fourth speed.
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3 phase , delta connection , 2 pole , 1000 Volt , 50 Hz asynchronous motor 2920 RPM
(friction losses will not be considered)
a) calculate the iron losses of the engine ?
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c)calculate the input power ?
d) effiency ?
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CRPET 2amEiNee 4 - Explain, resistance ? S - Why it without load 6 - Which is be wused in answer . in details, why it is necessary to is not possible to start the d. c. 2 use starting series motor perferable ( d. c. shunt or d. c. series motor ) to places require high starting torque ? prove your
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QUESTION from book ELECTRIC MACHINE-1
LAB BASESD QUESTION
Answer precisely keeping in view the experiments performed with the equipment in the lab.
iv. What effect will the load have on a DC shunt motor with significantly high armature resistance?v. For the four-point DC starter kit, what will happen if the series resistances are connected in reverseorder. Draw and explain how this combination is better than the 3 points started.
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Electric Motor Control
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- 1. Which NEC table is used to determine the full-load current of a torque motor? 2. What is the rated full-load current of a ¾-horsepower, 208-volt single-phase motor 3. What are the minimum allowable ampacities of the phase conductors and the neutral conductor that are to supply a 2-phase, 3-wire, 230-volt, 30-horsepower motor 4. . What is the full-load current of a 230-volt, 3-phase, 125-horsepower synchronous motor when it is operated at an 80% power factor?arrow_forwardExcitation circuit internal resistance of a shunt excited DC generator of 150 kW, 250 V, 1350 rpmRf = 10 Ω, armature circuit internal resistance Ra = 0.05 Ω. Excitation to adjust the end voltage of the machineA rheostat of Rreo = 40 has been installed in its circuit. Friction and ventilation losses are neglected.According to this,a) When the entire rheostat in the excitation circuit is activated and the generator is operating under rated conditions,a1) Calculate the load current, excitation and armature currents.a2) Calculate the emf induced in the armature and the power taken from the shaft.a3) Calculate the efficiency with the moment taken from the shaft.b) Spindle revolutions are reduced to n = 1000 rpm. In this case, Va = 250 V and Ea value in (a)What value should the rheostat be adjusted to keep the value found constant? In this new situationCalculate the power given. NOTE:3. In question (a), the excitation rheostat is fully activated. Pay attention to this. NOTE 2:Since a and b…arrow_forwardComplete the wiring diagrams as per Worksheets 5-A and 5-B then solve for "A" through "G" for the DC motor on Worksheets 5-A and 5-B when it is running at capacity and its specifications are as follows:Rated input = 125 volts, 16 ampsArmature Resistance = 0.3 ohms(Ω)Shunt Field Resistance = 50 ohms (Ω)Series Field Resistance = 0.6 ohm (Ω)Rheostat Resistance = 12.5 ohm (Ω)A) Voltage drop of armature (IR-arm)a) 4.05 V b) 120.95 V c) 125 V d) 129.5 VB) Voltage generated by motor (E-cemf)a) 4.05 V b) 120.95 V c) 125 V d) 129.5 VC) power consumed by shynt field(p-shunt)a) 54.68 W, b) 312.5 W, c) 1632.83 W, d) 2000 WD) power consumend by armature resistance( P-arm)a) 54.68 W , b) 312.5 W, c) 1632.83 W , d) 3000 Warrow_forward
- 18.a. Why are wound-rotor motors successful in controlling the speed of printing-press drives?A. The shared load is large and does not change rapidly.B. The press runs for long periods without showing the effects of load variations.C. The operating speed of the press is normally below 700/0 synchronous speedD. Few steps of rotor resistance are used, which allows for instant acceleration 18.b. A series d-c motor is most likely to be used on aA. compressorB. woodworking machineC. blower.D. hoistarrow_forwardIdentify the DC Motor used in Conveyor belt system. With a neat sketch explain its working. List it's advantages and disadvantages. - Reference must be added in slide. - Materials to be prepared apart from handout.arrow_forward3) total Armature Winding resistance and shunt area winding resistance of a self-excitation DC shunt motor0.22 Ω and 170Ω respectively. Motor armature coefficient Ka = 40. DC shunt motor, a mechanical loadit operates at 230V for feeding and is powered by a full load current of 40A. Flux per polethe value is known to be 50mWb. Brush-contact voltage drop is 2V. Core losses andthe total loss of Rotary parts is 450W. Answer the following. (d) input power, copper losses, brush-contact losses and total loss power values in the enginecalculate. (e) calculate the efficiency of the engine. (Understand the formulas you use for calculations, the names of the relevant parameters, and your processing stageswrite it down somehow.)arrow_forward
- A belt-driven 150 kW shunt wound DC generator is running at 500 rpm and is supplying full load to a bus bar at 230 V. At what speed will it run if the belt breaks and the machine continue to run taking 10 kW from the bus bar? The armature and the field resistances are 0.05 Ohm and 100 Ohms respectively. The brush contact drop is 150 Volts per brush. Neglect armature reaction.arrow_forward3) The total Armature Winding resistance and shunt area winding resistance of a self-excitation DC shunt motor0.22 Ω and 170Ω respectively. Motor armature coefficient Ka = 40. DC shunt motor, a mechanical loadit operates at 230V for feeding and is powered by a full load current of 40A. Flux per polethe value is known to be 50mWb. Brush-contact voltage drop is 2V. Core losses andthe total loss of Rotary parts is 450W. Answer the following. (a) Armature current value (b) induced voltage value in Armature (c) the speed of the Motor,arrow_forwarda 220-volt, 20-horsepower compound motor (long shunt) has an armature resistance of 0.25 ohm, series field resistance of 0.19 ohm, and shunt field resistance of 33 ohms. (a) calculate the current taken by the motor at the instant of starting if it is connected directly to the 220-volt line (b) calculate the current when the motor is running if the armature is developing 184-volts counter-emfarrow_forward
- Solve on keyboard clear and correct answer or will dislike In Induction motor, the load test has done. The result get is like the table below.1) Explain why the speed(rpm) is increase when voltage is increase?2) Explain why when the voltage reach in maximum the speed(rpm) is decrease?Answer all questions by explaination. Solve on keyboard clear and correct answer or will dislikearrow_forwardComplete the wiring diagrams as per Worksheets 6-A and 6-B then solve for "A" through "K" for the DC motor on Worksheets 6-A and 6-B when it is running at capacity and its specifications are as follows:Rated input = 125 volts, 16 ampsArmature Resistance = 0.3 ohms(Ω)Shunt Field Resistance = 50 ohms (Ω)Series Field Resistance 0.6 ohms (Ω)Rheostat Resistance = 12.5 ohms (Ω)A) voltage drop of series field (IR-series) a)4.12V b)9.6V c)111.29V d)115.4VB) voltage drop of armature (IR-arm)a)4.12V b)9.6V c)111.29V d)115.4VC) voltage generated by motor(E-cemf)a)4.12V b)9.6V c)111.29V d)115.4VD)power consumed by series field(P-series)a)56.58W b)153.6W c)265.42W d)1523.WE)power consumed by shunt field(P-shunt)a)56.58W b)153.6W c)265.42W d)1523.56WF)power consumed by armature resistance(P-arm)a)56.58W b)153.6W c)265.42W d)1523.56WG)percent efficiency of the machine( % eff) if rotational loses are 850 Wa)30% b)64% c)86% d)99%arrow_forward1. Explain the working Principle of Single Phase Induction Motor. 2. What are the different types of Starters to control AC-Motor. Explain briefly. 3. Explain DOL starter of Single Phase Induction Motor briefly. 4. What is the purpose of the magnetic contactor? 5. What is the use of auxiliary contact in the magnetic controller? 6. What happens when the holding coil gets the supply in the magnetic controller? 7. Explain the working principle of a relay.arrow_forward
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