Single-Phase Motors is one of 9 topics in the Grade 11 Electrical Technology CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. What is a defining characteristic of a universal motor?
It can run on either AC or DC supply
It can only run on three-phase AC supply
It requires no commutator or brushes at all
It cannot be used in portable power tools
Answer: It can run on either AC or DC supply — The universal motor is a specific motor type capable of running on either AC or DC supply (hence "universal"), common in small portable power tools requiring high speed in a compact size.
Easy
2. What kind of magnetic field does a single-phase winding alone produce, without any additional starting method?
A pulsating magnetic field that does not naturally rotate around the stator
A smoothly rotating magnetic field, identical to a three-phase supply
No magnetic field at all
A field that only exists during starting, never during running
Answer: A pulsating magnetic field that does not naturally rotate around the stator — A single-phase winding alone produces only a pulsating magnetic field, one that grows and shrinks and reverses direction but does not naturally rotate around the stator.
Medium
3. Name the general method that creates a second, phase-shifted magnetic field using an additional starting winding, to produce a genuinely rotating field for starting a single-phase motor.
Answer: split-phase — Split-phase methods create a second, phase-shifted magnetic field using an additional starting winding, so the combination produces a genuinely rotating field sufficient to start the motor.
