SACA C-202 ELECTRIC MOTOR CONTROL
SYSTEMS EXAM 2026 | ACTUAL EXAM
QUESTIONS WITH VERIFIED CORRECT
SOLUTIONS & DETAILED RATIONALES | LATEST
VERSION
SACA C-202 — ELECTRIC MOTOR CONTROL SYSTEMS EXAM
ACTUAL EXAM QUESTIONS WITH VERIFIED CORRECT SOLUTIONS & DETAILED
RATIONALE | LATEST VERSION
400 QUESTIONS | MULTIPLE CHOICE (A–E)
Q1. What is the primary function of a motor control system?
A. To convert mechanical energy into electrical energy B. To supply raw power to a
motor without regulation C. To start, stop, protect, and control the speed or direction of
an electric motor D. To measure the resistance of motor windings E. To convert AC
power into DC power exclusively
✔ CORRECT ANSWER: C RATIONALE: A motor control system is designed to
safely start, stop, protect, and in many cases control the speed or direction of an electric
motor, making option C the most complete and accurate description.
Q2. Which law states that the current through a conductor is directly proportional
to the voltage across it?
A. Faraday's Law B. Lenz's Law C. Kirchhoff's Voltage Law D. Ohm's Law E.
Coulomb's Law
✔ CORRECT ANSWER: D RATIONALE: Ohm's Law states V = IR, meaning
current is directly proportional to voltage and inversely proportional to resistance. It is a
fundamental principle used throughout motor control circuit analysis.
Q3. A motor nameplate reads 460V, 3-phase, 60 Hz, 20 HP. What is the
approximate full-load current (FLC)?
A. 10 A B. 16 A C. 24 A D. 32 A E. 48 A
,✔ CORRECT ANSWER: C RATIONALE: Using the formula I = (HP × 746) / (√3 ×
V × η × PF), a 20 HP, 460V, 3-phase motor typically draws approximately 24 A at full
load, consistent with NEC Table 430.250 values.
Q4. Which component in a motor control circuit provides overload protection?
A. Fuse B. Circuit breaker C. Contactor D. Overload relay E. Disconnect switch
✔ CORRECT ANSWER: D RATIONALE: The overload relay monitors motor
current and trips when excessive current is detected over time, protecting the motor
from thermal damage due to overloading. Fuses and breakers protect against short
circuits, not sustained overloads.
Q5. What does NEMA stand for in the context of motor standards?
A. National Electrical Manufacturers Association B. National Energy Management
Authority C. North American Electrical Motor Assembly D. National Equipment
Maintenance Association E. Network of Electrical Motor Applications
✔ CORRECT ANSWER: A RATIONALE: NEMA stands for National Electrical
Manufacturers Association. It develops standards for electrical equipment including
motors, enclosures, and control devices used throughout North America.
Q6. In a three-phase induction motor, what is the relationship between
synchronous speed and the number of poles?
A. Speed increases as poles increase B. Speed is independent of poles C. Speed
decreases as poles increase D. Speed doubles with every additional pole pair E.
Speed is only affected by frequency, not poles
✔ CORRECT ANSWER: C RATIONALE: Synchronous speed Ns = 120f/P, where
f is frequency and P is the number of poles. As the number of poles increases,
synchronous speed decreases proportionally.
Q7. What is the synchronous speed of a 4-pole, 60 Hz induction motor?
A. 900 RPM B. 1200 RPM C. 1500 RPM D. 1800 RPM E. 3600 RPM
,✔ CORRECT ANSWER: D RATIONALE: Ns = 120 × = = 1800
RPM. This is the synchronous speed; the actual rotor speed will be slightly less due to
slip.
Q8. What is slip in an induction motor?
A. The difference between rated and no-load current B. The ratio of rotor speed to
synchronous speed C. The difference between synchronous speed and actual rotor
speed D. The phase angle between voltage and current E. The thermal loss in the
stator windings
✔ CORRECT ANSWER: C RATIONALE: Slip = Ns − Nr, where Ns is
synchronous speed and Nr is rotor speed. It is the speed difference necessary for the
rotating magnetic field to induce current in the rotor, producing torque.
Q9. What type of motor is most commonly used in industrial applications?
A. DC series motor B. Synchronous motor C. Three-phase squirrel-cage induction motor
D. Single-phase capacitor-start motor E. Universal motor
✔ CORRECT ANSWER: C RATIONALE: The three-phase squirrel-cage induction
motor is the most widely used industrial motor due to its simplicity, robustness, low
maintenance, and good efficiency across a wide power range.
Q10. Which starting method connects a motor directly to the supply voltage?
A. Star-delta starting B. Autotransformer starting C. Soft starter method D. Direct-on-line
(DOL) starting E. Variable frequency drive starting
✔ CORRECT ANSWER: D RATIONALE: Direct-on-line (DOL) starting connects
the motor directly across the full supply voltage. It produces high starting current
(typically 6–8× FLC) but is simple and inexpensive for smaller motors.
Q11. In a star-delta starter, what is the starting voltage applied to each motor
winding during the star phase?
A. Full line voltage B. 86.6% of line voltage C. 57.7% of line voltage D. 50% of line
voltage E. 33.3% of line voltage
, ✔ CORRECT ANSWER: C RATIONALE: In star connection, each winding
receives the phase voltage = line voltage / √3 ≈ 57.7% of line voltage. This reduces
starting current to approximately 1/3 of DOL starting current.
Q12. What is a contactor?
A. A device that measures motor temperature B. A current-limiting resistor in series with
the motor C. An electromagnetically operated switching device used to connect and
disconnect power circuits D. A mechanical relay that provides overload protection E.
A transformer used to step down control voltage
✔ CORRECT ANSWER: C RATIONALE: A contactor is an electromagnetically
operated device used to repeatedly establish and interrupt electrical power circuits. It
consists of a coil, main contacts, and auxiliary contacts.
Q13. What is the purpose of auxiliary contacts on a contactor?
A. To carry main load current to the motor B. To provide overload protection C. To be
used in the control circuit for interlock, sealing, and signal functions D. To measure
power factor E. To regulate coil voltage
✔ CORRECT ANSWER: C RATIONALE: Auxiliary contacts are low-current
contacts used in control circuits. They perform functions such as sealing in a contactor
after a pushbutton is released, providing interlocks, and signaling.
Q14. What is a "seal-in" or "holding" circuit in motor control?
A. A circuit that seals the motor housing against moisture B. A circuit that uses an
auxiliary contact to maintain contactor energization after the start button is released
C. A circuit that prevents overload relay reset D. A circuit used in reversing applications
only E. A circuit that seals current at a fixed value
✔ CORRECT ANSWER: B RATIONALE: A seal-in circuit uses a normally open
auxiliary contact wired in parallel with the start pushbutton. Once the contactor
energizes, this contact closes and maintains current flow through the coil even after the
start button is released.
Q15. Which type of overload relay uses a bimetallic element?
SYSTEMS EXAM 2026 | ACTUAL EXAM
QUESTIONS WITH VERIFIED CORRECT
SOLUTIONS & DETAILED RATIONALES | LATEST
VERSION
SACA C-202 — ELECTRIC MOTOR CONTROL SYSTEMS EXAM
ACTUAL EXAM QUESTIONS WITH VERIFIED CORRECT SOLUTIONS & DETAILED
RATIONALE | LATEST VERSION
400 QUESTIONS | MULTIPLE CHOICE (A–E)
Q1. What is the primary function of a motor control system?
A. To convert mechanical energy into electrical energy B. To supply raw power to a
motor without regulation C. To start, stop, protect, and control the speed or direction of
an electric motor D. To measure the resistance of motor windings E. To convert AC
power into DC power exclusively
✔ CORRECT ANSWER: C RATIONALE: A motor control system is designed to
safely start, stop, protect, and in many cases control the speed or direction of an electric
motor, making option C the most complete and accurate description.
Q2. Which law states that the current through a conductor is directly proportional
to the voltage across it?
A. Faraday's Law B. Lenz's Law C. Kirchhoff's Voltage Law D. Ohm's Law E.
Coulomb's Law
✔ CORRECT ANSWER: D RATIONALE: Ohm's Law states V = IR, meaning
current is directly proportional to voltage and inversely proportional to resistance. It is a
fundamental principle used throughout motor control circuit analysis.
Q3. A motor nameplate reads 460V, 3-phase, 60 Hz, 20 HP. What is the
approximate full-load current (FLC)?
A. 10 A B. 16 A C. 24 A D. 32 A E. 48 A
,✔ CORRECT ANSWER: C RATIONALE: Using the formula I = (HP × 746) / (√3 ×
V × η × PF), a 20 HP, 460V, 3-phase motor typically draws approximately 24 A at full
load, consistent with NEC Table 430.250 values.
Q4. Which component in a motor control circuit provides overload protection?
A. Fuse B. Circuit breaker C. Contactor D. Overload relay E. Disconnect switch
✔ CORRECT ANSWER: D RATIONALE: The overload relay monitors motor
current and trips when excessive current is detected over time, protecting the motor
from thermal damage due to overloading. Fuses and breakers protect against short
circuits, not sustained overloads.
Q5. What does NEMA stand for in the context of motor standards?
A. National Electrical Manufacturers Association B. National Energy Management
Authority C. North American Electrical Motor Assembly D. National Equipment
Maintenance Association E. Network of Electrical Motor Applications
✔ CORRECT ANSWER: A RATIONALE: NEMA stands for National Electrical
Manufacturers Association. It develops standards for electrical equipment including
motors, enclosures, and control devices used throughout North America.
Q6. In a three-phase induction motor, what is the relationship between
synchronous speed and the number of poles?
A. Speed increases as poles increase B. Speed is independent of poles C. Speed
decreases as poles increase D. Speed doubles with every additional pole pair E.
Speed is only affected by frequency, not poles
✔ CORRECT ANSWER: C RATIONALE: Synchronous speed Ns = 120f/P, where
f is frequency and P is the number of poles. As the number of poles increases,
synchronous speed decreases proportionally.
Q7. What is the synchronous speed of a 4-pole, 60 Hz induction motor?
A. 900 RPM B. 1200 RPM C. 1500 RPM D. 1800 RPM E. 3600 RPM
,✔ CORRECT ANSWER: D RATIONALE: Ns = 120 × = = 1800
RPM. This is the synchronous speed; the actual rotor speed will be slightly less due to
slip.
Q8. What is slip in an induction motor?
A. The difference between rated and no-load current B. The ratio of rotor speed to
synchronous speed C. The difference between synchronous speed and actual rotor
speed D. The phase angle between voltage and current E. The thermal loss in the
stator windings
✔ CORRECT ANSWER: C RATIONALE: Slip = Ns − Nr, where Ns is
synchronous speed and Nr is rotor speed. It is the speed difference necessary for the
rotating magnetic field to induce current in the rotor, producing torque.
Q9. What type of motor is most commonly used in industrial applications?
A. DC series motor B. Synchronous motor C. Three-phase squirrel-cage induction motor
D. Single-phase capacitor-start motor E. Universal motor
✔ CORRECT ANSWER: C RATIONALE: The three-phase squirrel-cage induction
motor is the most widely used industrial motor due to its simplicity, robustness, low
maintenance, and good efficiency across a wide power range.
Q10. Which starting method connects a motor directly to the supply voltage?
A. Star-delta starting B. Autotransformer starting C. Soft starter method D. Direct-on-line
(DOL) starting E. Variable frequency drive starting
✔ CORRECT ANSWER: D RATIONALE: Direct-on-line (DOL) starting connects
the motor directly across the full supply voltage. It produces high starting current
(typically 6–8× FLC) but is simple and inexpensive for smaller motors.
Q11. In a star-delta starter, what is the starting voltage applied to each motor
winding during the star phase?
A. Full line voltage B. 86.6% of line voltage C. 57.7% of line voltage D. 50% of line
voltage E. 33.3% of line voltage
, ✔ CORRECT ANSWER: C RATIONALE: In star connection, each winding
receives the phase voltage = line voltage / √3 ≈ 57.7% of line voltage. This reduces
starting current to approximately 1/3 of DOL starting current.
Q12. What is a contactor?
A. A device that measures motor temperature B. A current-limiting resistor in series with
the motor C. An electromagnetically operated switching device used to connect and
disconnect power circuits D. A mechanical relay that provides overload protection E.
A transformer used to step down control voltage
✔ CORRECT ANSWER: C RATIONALE: A contactor is an electromagnetically
operated device used to repeatedly establish and interrupt electrical power circuits. It
consists of a coil, main contacts, and auxiliary contacts.
Q13. What is the purpose of auxiliary contacts on a contactor?
A. To carry main load current to the motor B. To provide overload protection C. To be
used in the control circuit for interlock, sealing, and signal functions D. To measure
power factor E. To regulate coil voltage
✔ CORRECT ANSWER: C RATIONALE: Auxiliary contacts are low-current
contacts used in control circuits. They perform functions such as sealing in a contactor
after a pushbutton is released, providing interlocks, and signaling.
Q14. What is a "seal-in" or "holding" circuit in motor control?
A. A circuit that seals the motor housing against moisture B. A circuit that uses an
auxiliary contact to maintain contactor energization after the start button is released
C. A circuit that prevents overload relay reset D. A circuit used in reversing applications
only E. A circuit that seals current at a fixed value
✔ CORRECT ANSWER: B RATIONALE: A seal-in circuit uses a normally open
auxiliary contact wired in parallel with the start pushbutton. Once the contactor
energizes, this contact closes and maintains current flow through the coil even after the
start button is released.
Q15. Which type of overload relay uses a bimetallic element?
