Free mock exam
Motors, starters and control — Industrial Electrical Practice
Free topic-focused mock exam: all 30 questions on Motors, starters and control, drawn from the wider Industrial Electrical bank. 35-minute timer, 70% to pass, worked explanation on every question. Use this when you've taken the full mock once and want to drill the topics you got wrong.
- Questions
- 30
- Time limit
- 35 min
- Pass mark
- 70% · 21/30
- Question bank
- 30
Free, no sign-up. Retake as many times as you like — the questions are reshuffled, with the answer order changed.
Sample questions
01The motor on an existing star-delta starter has burnt out. What must the replacement motor be?
- ADesigned to run in delta at the supply voltage, six terminals
- BWound to run in star at half the supply voltage, six terminals
- CAny motor of the same kW and frame, with three terminals
- DWound to run in star at the supply voltage, three terminals
Why: A star-delta starter only works with a motor designed to run in delta at the supply voltage, with all six winding ends brought out. It starts the windings in star and then switches them to delta. A motor wound to run in star is the tempting wrong answer, but in the running position the starter connects the windings in delta, and a three-terminal motor cannot be reconnected at all.
02Which part of a variable speed drive can still hold a dangerous charge after the supply has been switched off?
- AThe rectifier diodes at the input
- BThe inverter output terminals only
- CThe keypad and its display board
- DThe DC link capacitors inside it
Why: A drive rectifies the supply to DC, smooths and stores it in the DC link capacitors, then inverts it back to AC. Those capacitors can stay charged after the supply is off, which is why a drive carries a discharge time and BS 7671 462.4 deals with residual energy. The output terminals are tempting because they connect to the motor, but the stored energy sits in the DC link.
03A large fan on a weak supply needs a gentle start, and the process now needs it to run at different speeds. Which starting method suits both needs?
- AA DOL starter with a class 30 overload
- BA soft starter with an internal bypass
- CA star-delta starter with a long timer
- DA variable speed drive for the fan
Why: A drive varies the frequency, starts the motor at around rated current and can run it at any speed the process needs. A soft starter is tempting because it gives a gentle start, but it only ramps the voltage at mains frequency, so it cannot change the running speed. Star-delta and DOL are fixed-speed methods with heavier starting currents.
Common questions
Is the Motors, starters and control mock exam free?
Yes — 100% free, no sign-up needed. Questions are pulled at random from a substantial bank, with a worked explanation on every question after you submit.
Can I retake the mock exam?
Yes. Every attempt picks a different random selection and reshuffles the options, so each retake gives you genuinely new questions. No limit on retakes.
Does this count towards the real qualification?
No — this is independent practice material. To gain the actual qualification you need to sit the official assessment through an approved provider.