Why is a starting resistor needed to bring amotor up to speed?Show one way to reverse the direction of ro-tation of a compound motor.

Why is a Starting Resistor Needed for a Motor?A starting resistor is used in motors, especially DC…

Answered: Why is a starting resistor needed to…

Electricity for Refrigeration, Heating, and Air Conditioning (MindTap Course List)

10th Edition

ISBN:9781337399128

Author:Russell E. Smith

Publisher:Russell E. Smith

Chapter8: Basic Electric Motors

Section: Chapter Questions

Problem 19RQ

See similar textbooks

Similar questions

Why there is need of starter in the 3-phase induction motor?
A 60-Hz induction motor is needed to drive a load at approximately 850 rpm. How many poles should the motor have? What is the slip of this motor for a speed of 850 rpm?
What are the advantages and disadvantages of using the following types of motors? shaded-pole motor PSC motor split-phase motor capacitor-start–capacitor-run motor
1- What causes a three-phase motor to run backwards? 2- How we can reverse the direction of the induction motor? 3- What are the advantages of changing the direction of an induction motor for a 3-phase? 4- What is a forward reversing motor control circuit? 5- What is the application of the forward and reverse motor? 6- Why do we change the direction of the rotation of a 3-phase induction motor?
A 4-pole, 50 Hz, 3-phase induction motor has a rotor resistance/phase of 0.03 ohm and reactance of 0.12 ohm per phase. What is the value of speed at maximum torque?
Why is the starting torque of a wound-rotor motor higher per ampere of starting current than that of a squirrel-cage motor
P-1).. Which of the following determine the amount of torque produced by a single-phase split-phase motor? a) The strength of the magnetic field of the stator b) The strength of the magnetic field of the rotor c) The phase angle difference between the current in the start winding and the current in the run winding d) all of the above P-2). The phase angle difference between the currents in the start winding and run winding of a single-phase split-phase motor is typically 90 degrees. a) true b) false P-3). A centrifugal switch is used to disconnect the________ winding of a non-hermetically sealed single-phase split-phase motor at approximately 75% of rated speed. a) run b) start c) either "a" or "b" d) neither "a" nor "b" P-4). Where an internal centrifugal switch cannot be used, an external______ relay can be used to perform the same function in a single-phase split-phase motor. a) hot-wire b) current c) solid-state starting d) all of the above
Why, for a given induction motor, might it be possible to employ direct-on-line starting in one application, but be necessary to employ a starter in another application?
A three – phase 400 V, 50 Hz induction motor has a speed of 900 rpm on full – load. The motor has six poles. How many complete alternations will the rotor voltage takes per minute? (a). 30 (b). 60 (c). 300 (d). 600
Q14/ If the star-connected rotor winding of a 3-phase induction motor has a resistance of 0.01 per phase and a standstill reactance of 0.08 2 per phase, what must be the value of resistance per phase of the stator to give a maximum starting torque? What is the percentage slip when the starting resistance has been reduced to 0.0252 per phase if the motor is still exerting the maximum torque? Ans[0.0792; 37.5%]
The angle between rotor teeth of permanent magnet stepper motor is 1.8° and there are five stator phases in this motor. What is the step angle in degrees of this motor?
List three methods that can be used to control the speed of dc motors. Which of these apply to shunt-connected motors? To separately excited motors? To permanent-magnet motors? To series-connected motors?

SEE MORE QUESTIONS

Recommended textbooks for you

Electricity for Refrigeration, Heating, and Air C…

Mechanical Engineering

ISBN:

9781337399128

Author:

Russell E. Smith

Publisher:

Cengage Learning

Delmar's Standard Textbook Of Electricity

Electrical Engineering

ISBN:

9781337900348

Author:

Stephen L. Herman

Publisher:

Cengage Learning

Electricity for Refrigeration, Heating, and Air C…

Mechanical Engineering

ISBN:

9781337399128

Author:

Russell E. Smith

Publisher:

Cengage Learning

Delmar's Standard Textbook Of Electricity

Electrical Engineering

ISBN:

9781337900348

Author:

Stephen L. Herman

Publisher:

Cengage Learning

SEE MORE TEXTBOOKS

Why is a starting resistor needed to bring a motor up to speed? Show one way to reverse the direction of ro- tation of a compound motor.