Concept explainers
What are the disadvantages of low-speed, directly coupled induction motors?
The disadvantages of low-speed, directly coupled induction motor.
Explanation of Solution
The directly coupled induction motors are rarely used in the applications where the required speed is below 500rpm. The induction motor take very less current from the supply main.
The vector sum of load current and magnetizing current lags voltage by around 75-80 degrees and hence, the power factor is low. Due to high magnetizing current, the copper losses of the motor increase. This in turn leads to decrease in the efficiency of the motor.
Thus Disadvantage of low-speed, directly coupled induction motors are low power factor and low efficiency.
Want to see more full solutions like this?
Chapter 43 Solutions
MindTap for Herman's Understanding Motor Controls, 4th Edition [Instant Access], 2 terms
- What is the advantage of consequent pole motors over some other types of variable speed motors?arrow_forwardWhat are the three basic types of direct current motors?arrow_forwardWhy can a multispeed fan motor be operated at lower speed than most induction motors without harm to the motor windings?arrow_forward
- What is the most common NEMA design code found on squirrel- cagetype motors?arrow_forwardTrue or False: Three-phase motors have low starting torque.arrow_forwardWhen a repulsion-start induction-run motor reaches about 75% of rated full-load speed, it stops operating as a repulsion motor and starts operating as a squirrel-cage motor. What must be done to cause the motor to begin operating as a squirrel-cage motor?arrow_forward
- Understanding Motor ControlsMechanical EngineeringISBN:9781337798686Author:Stephen L. HermanPublisher:Delmar Cengage LearningElectrical Transformers and Rotating MachinesMechanical EngineeringISBN:9781305494817Author:Stephen L. HermanPublisher:Cengage LearningRefrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning