Discussion
Consider the following statements about dc motors.
1. Torque is proportional to flux times armature current.
2. Speed is proportional to back emf divided by flux.
3. A series motor may be run on no load.
Which are correct?
Answer: D
Correct answer: 1 and 2 only
Statements 1 and 2 are the two governing relations, \( T = k\Phi I_a \) and \( N \propto E/\Phi \). Statement 3 is the dangerous one: a series motor on no load has almost no field current, so its flux collapses and its speed rises without limit until the armature bursts. It must always be coupled directly to its load, never through a belt that could break.
No comment is present. Be the first to comment.
Loading…
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development