Motors & Variable Speed Drives
How three-phase induction motors work, how to read a nameplate, starting methods, what a variable speed drive does, and how to spot and prevent common motor failures. For technicians and operators who work around motor-driven equipment.
55m
Total time
4
Competency levels
12
Lessons
What you'll learn
- Explain in plain terms how a three-phase induction motor produces rotation.
- Interpret every field on a motor nameplate, including kW, voltage, current, speed, duty, IP rating and insulation class.
- Compare direct-on-line, star-delta and soft-start starting methods and state when each is appropriate.
- Explain what a variable speed drive (VSD) does and why it saves energy on pumps and fans.
- Recognise the common motor failure modes — insulation breakdown, bearing failure and VSD-induced bearing currents — and the protection that guards against overload and single-phasing.
- Carry out routine motor checks and report early warning signs before they become failures.
Curriculum
Progress through each competency level in order.
1
Awareness
- 3mHow an induction motor works — in plain termsKnowledge
- 3mReading a motor nameplateKnowledge
- 7mAwareness check — motor basics and nameplatesAssessment
2
Knowledge
- 3mStarting methods: DOL, star-delta and soft startKnowledge
- 3mWhat a VSD does — and why it saves energy on pumps and fansKnowledge
- 8mKnowledge check — starting methods and VSDsAssessment
3
Skill
- 3mFailure modes and motor protectionKnowledge
- 3mMotor and drive field surveyAssignment
- 8mSkill check — failures, protection and routine checksAssessment
4
Mastery
- 3mDiagnosing motor and drive problems systematicallyKnowledge
- 3mLead a motor reliability investigationAssignment
- 8mMastery assessment — motors and drives in practiceAssessment
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