Electric Motor Control
10th Edition
ISBN: 9781133702818
Author: Herman
Publisher: CENGAGE L
expand_more
expand_more
format_list_bulleted
Videos
Textbook Question
Chapter 26, Problem 5SQ
What is meant by the low or poor starting economy of a primary resistor starter?
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
L-1). The 3-phase wound-rotor induction motor has .... . a) high starting torque b) low starting current c) both "a" and "b" d) neither "a" nor "b" L-2). The 3-phase wound-rotor induction.........a) motor has a wire wound rotor b) motor's rotor can be connected to an external resistive load by way of slip rings and brushes c) motor requires more maintenance than the 3-phase squirrel-cage induction motor d) all of the above L-3). The 3-phase wound-rotor induction motor's rotor circuit's resistance should be adjusted so it is__________ during starting. a) low b) high c) either "a" or "b" d) neither "a" nor "b" L-4). Will a 3-phase wound-rotor induction motor start with no external circuit connected to its rotor leads? a) yes b) no
Find the number of resistance sections and the resistance of each section of a starter for a 3.7 kW, 230 V, dC series motor from the following data:-Starting current varies from 1 to 1.5 times full load current Full load efficiency = 85%
Motor circuit resistance 1.4 ohm
Assume flux increases by 10% as the current rises from 1 to 1.5 times the rated full load current.
7- The increase of the DC voltage feeding the switched reluctance motor will increase:
a- Its speed. b- Its torque.
c- Its efficiency.
8- The increase of the DC voltage feeding the stepper motor will increase:
a- Its slew range.
b- Its efficiency c- Its reliability
9- The reluctance motor is used in applications in:
a- Calm environment. b- Harsh environment.
c- Polluted environment.
10- The stepper motor used in a- Position control application.
b- High speed applications. c- Heavy duty applications.
Chapter 26 Solutions
Electric Motor Control
Ch. 26 - What is the purpose of inserting resistance in the...Ch. 26 - Why is the power not interrupted when the motor...Ch. 26 - If the starter is to function properly and a...Ch. 26 - How may additional steps of acceleration be added?Ch. 26 - What is meant by the low or poor starting economy...Ch. 26 - Prob. 6SQ
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.Similar questions
- Q2 A DC shunt motor is connected to a 220 V supply. Figurel below shows the time/current characteristics with a resistance starter. If armature resistance is 0.12 0, a) What is the maximum current that is flowing in the armature at the instant of starting? b) What is the minimum current in the armature? c) How many sections does this starter resistance have? Show your work. d) Calculate the required starter resistance required to limit the current to the maximum value. 270 162 t2 tsarrow_forwardQ2 A DC shunt motor is connected to a 220 V supply. Figurel below shows the time/current characteristics with a resistance starter. If armature resistance is 0.12 0, a) What is the maximum current that is flowing in the armature at the instant of starting? b) What is the minimum current in the armature? c) How many sections does this starter resistance have? Show your work. d) Calculate the required starter resistance required to limit the current to the maximum value. 270 162 13 t.arrow_forward4- A 3-phase A -connected 220-V (line-to-neutral), 60-Hz 6-pole induction motor has the following parameter values in O/phase referred to the stator: R1 = 0.294, R2 = 0.144, X, = 0.503, X2 = 0.209, Xm= 13.25. The total friction, windage, and core losses may be assumed to be constant at 403 W, independent of load. For a slip of 5%, a. Output torque b. Stator current, c. Power factor, d. Converted power e. Efficiency.arrow_forward
- Subject / speed control Of Separately Excited Shunt DC Motor Q/Mention the advantages and disadvantages of each method 1-Armature Voltage control 2-Field control 3-Armature resistanc controlarrow_forward3.62 A squirrel cage induction motor having a rated slip of 2% on full load has a starting torque of 50% of full load torque. The starting current is (a) Two times the full load current (b) Four times the full load current (c) Five times the full load current (d) Equal to the full load currentarrow_forwardI will be grateful thanks a lot. An automatic starter circuit is to be designed for a shunt motor rated at 20 hp, 240 V, and 75 A. The armature resistance of the motor is 0.12 W, and the shunt field resistance is 40 W. The motor is to start with no more than 250 percent of its rated armature current, and as soon as the current falls to rated value, a starting resistor stage is to be cut out. How many stages of starting resistance are needed, and how big should each one be?arrow_forward
- 53. A 200 W, 230 V, 50 Hz capacitor-start mo- tor has the following winding parameters: Main winding: R = 4·5 Q2 ; X₁ = 3·7 Q What should be the angle between input voltage and starting winding current to give maximum starting torque? (1) 38.2⁰ (iii) 50-4⁰ (ii) 24-6° (iv) 32.7°arrow_forwardA 500-V, 37.3 kW, 1000 RPM DC shunt motor has on full-load an efficiency of 90 percent. The armature circuit resistance is 0.24 and there is total voltage drop of 2 V at the brushes. The field current is 1.8 A. Determine total resistance in motor starter to limit the starting armature current to 1.5 times the full-armature current.arrow_forwardA switched reluctance motor has salient poles on ..................... a. neither stator or rotor b. Stator and rotor c. Rotor only d. Stator onlyarrow_forward
- Question 5 A 200 HP, 440 V, 1440 rpm, 50 Hz induction motor has a power factor of 0.85 lagging and an efficiency of 90% at full load. If started with rated voltage (DOL), the starting current is 6 times greater than the rated current of the motor. a. Determine the rated current and starting current of the motor with DOL start. ( b. Determine the starting current of the motor with star-delta. C. Determine the tap setting of an autotransformer if the starting curent needed to be the same as the star-delta start.arrow_forwardWhy there is need of starter in the 3-phase induction motor?arrow_forwardA 100-hp, 250- V, 400-A shunt DC motor with an armature resistance of 0.05Ω. It is desired to design a starter circuit for this motor which will limit the maximum starting current to 150% of its rated value and which will switch out sections of resistance as the armature current falls to its rated value. How many stages of starting resistance will be required to limit the current to the range specified? What must the value of each segment of the resistor be? At what voltage should each stage of the starting resistance be cut out?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Power System Stability in C# Part 1: Fundamentals of Stability Analysis; Author: EETechStuff;https://www.youtube.com/watch?v=SaT9oWcHgKw;License: Standard Youtube License