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SACA C-202 Electric Motor Control
Systems Actual Exam 2026/2027 |
Questions with Verified Answers | 100%
Correct | Pass Guaranteed
Q001: A 480 V, 3-phase, 25 HP squirrel-cage induction motor is started with a full-
voltage non-reversing (FVNR) starter. If the motor nameplate full-load current
(FLC) is 32 A, what is the maximum allowable rating of the inverse-time circuit
breaker protecting the motor branch circuit per NEC 430.52?
Options:
A. 40 A
B. 50 A
C. 80 A
D. 100 A
ANSWER: C
Verified Solution: NEC 430.52(C)(1) permits an inverse-time breaker at 250 % of
FLC: 32 A × 2.5 = 80 A.
Q002: In a ladder diagram for a two-wire control circuit, the holding contact is
wired in parallel with the start push button. If the holding contact fails open, which
symptom will occur?
Options:
A. Motor will not stop
B. Motor starts but stops when start button is released
C. Contactor coil remains energized continuously
D. Overload relay trips instantly
ANSWER: B
, 2
Verified Solution: Without the sealing contact, coil power is lost when the start
button is released; motor therefore stops immediately after release.
Q003: A VFD displays “Undervolt” during acceleration. Line-side voltage
measures 480 V balanced. Which parameter is the most likely cause?
Options:
A. Carrier frequency set too high
B. DC-bus pre-charge resistor open
C. Acceleration ramp set too fast
D. Motor nameplate voltage is 460 V
ANSWER: C
Verified Solution: Rapid acceleration causes high inrush to the DC bus; bus voltage
sags below threshold and VFD faults. Slowing the ramp prevents the sag.
Q004: A 120 V control circuit uses a ice-cube relay with a 24 VDC coil. The relay
chatters. Supply voltage at coil terminals reads 18 VDC. Which action is correct?
Options:
A. Increase PLC output fuse rating
B. Replace power supply; output is low
C. Add a bleeder resistor across coil
D. Swap relay for 120 VAC coil model
ANSWER: B
Verified Solution: Coil voltage must be ±10 % of rating; 18 V is 25 % low, causing
chatter. A failing supply is the root cause.
Q005: A 3-wire control circuit uses a momentary START and STOP button. After
wiring, the motor starts but will not stop when STOP is pressed. Which wiring
error exists?
Options:
, 3
A. STOP button is wired in parallel with START
B. Control transformer primary is open
C. Holding contact is welded closed
D. STOP button is wired in series with coil but NC contact is missing
ANSWER: D
Verified Solution: Without a normally-closed STOP contact in series, pressing
STOP does not interrupt coil current; motor continues to run.
Q006: A 460 V, 50 HP motor is controlled by a VFD. The motor nameplate lists 65
A FLC. What is the minimum ampacity of the branch-circuit conductors per NEC
430.22?
Options:
A. 65 A
B. 75 A
C. 81.25 A
D. 100 A
ANSWER: C
Verified Solution: NEC 430.22 requires conductors at 125 % of FLC: 65 A × 1.25
= 81.25 A.
Q007: A PLC ladder program uses a TON timer with preset 5.0 s and time base
0.01 s. If the accumulated value reads 250, how much time has elapsed?
Options:
A. 0.25 s
B. 2.5 s
C. 25 s
D. 250 s
ANSWER: B
, 4
Verified Solution: Accumulated value × time base = 250 × 0.01 s = 2.5 s elapsed.
Q008: A motor control center (MCC) bucket contains a size 3 reversing contactor.
The mechanical interlock fails. Which consequence is most likely?
Options:
A. Coil burnout on both contactors
B. Short-circuit between line phases if both close
C. Motor runs in forward only
D. Overload relay nuisance trips
ANSWER: B
Verified Solution: Without interlock, both contactors can close simultaneously,
creating a phase-to-phase short across the line.
Q009: A VFD is programmed for 2-wire control, source mode. The run command
is wired to a maintained contact. The motor will not start. Voltage at run terminal is
0 V when contact is closed. Which fault exists?
Options:
A. Contact is wired to sink mode terminal
B. Analog speed reference is missing
C. DC injection braking is enabled
D. Motor thermistor is open
ANSWER: A
Verified Solution: Source mode expects +24 V on run terminal; wiring to sink
terminal keeps terminal at 0 V—no start command.
Q010: A 480 V motor branch circuit uses a 100 A inverse-time breaker and 100 A
fuses in series for backup protection. Which NEC section prohibits this
arrangement?
Options:
SACA C-202 Electric Motor Control
Systems Actual Exam 2026/2027 |
Questions with Verified Answers | 100%
Correct | Pass Guaranteed
Q001: A 480 V, 3-phase, 25 HP squirrel-cage induction motor is started with a full-
voltage non-reversing (FVNR) starter. If the motor nameplate full-load current
(FLC) is 32 A, what is the maximum allowable rating of the inverse-time circuit
breaker protecting the motor branch circuit per NEC 430.52?
Options:
A. 40 A
B. 50 A
C. 80 A
D. 100 A
ANSWER: C
Verified Solution: NEC 430.52(C)(1) permits an inverse-time breaker at 250 % of
FLC: 32 A × 2.5 = 80 A.
Q002: In a ladder diagram for a two-wire control circuit, the holding contact is
wired in parallel with the start push button. If the holding contact fails open, which
symptom will occur?
Options:
A. Motor will not stop
B. Motor starts but stops when start button is released
C. Contactor coil remains energized continuously
D. Overload relay trips instantly
ANSWER: B
, 2
Verified Solution: Without the sealing contact, coil power is lost when the start
button is released; motor therefore stops immediately after release.
Q003: A VFD displays “Undervolt” during acceleration. Line-side voltage
measures 480 V balanced. Which parameter is the most likely cause?
Options:
A. Carrier frequency set too high
B. DC-bus pre-charge resistor open
C. Acceleration ramp set too fast
D. Motor nameplate voltage is 460 V
ANSWER: C
Verified Solution: Rapid acceleration causes high inrush to the DC bus; bus voltage
sags below threshold and VFD faults. Slowing the ramp prevents the sag.
Q004: A 120 V control circuit uses a ice-cube relay with a 24 VDC coil. The relay
chatters. Supply voltage at coil terminals reads 18 VDC. Which action is correct?
Options:
A. Increase PLC output fuse rating
B. Replace power supply; output is low
C. Add a bleeder resistor across coil
D. Swap relay for 120 VAC coil model
ANSWER: B
Verified Solution: Coil voltage must be ±10 % of rating; 18 V is 25 % low, causing
chatter. A failing supply is the root cause.
Q005: A 3-wire control circuit uses a momentary START and STOP button. After
wiring, the motor starts but will not stop when STOP is pressed. Which wiring
error exists?
Options:
, 3
A. STOP button is wired in parallel with START
B. Control transformer primary is open
C. Holding contact is welded closed
D. STOP button is wired in series with coil but NC contact is missing
ANSWER: D
Verified Solution: Without a normally-closed STOP contact in series, pressing
STOP does not interrupt coil current; motor continues to run.
Q006: A 460 V, 50 HP motor is controlled by a VFD. The motor nameplate lists 65
A FLC. What is the minimum ampacity of the branch-circuit conductors per NEC
430.22?
Options:
A. 65 A
B. 75 A
C. 81.25 A
D. 100 A
ANSWER: C
Verified Solution: NEC 430.22 requires conductors at 125 % of FLC: 65 A × 1.25
= 81.25 A.
Q007: A PLC ladder program uses a TON timer with preset 5.0 s and time base
0.01 s. If the accumulated value reads 250, how much time has elapsed?
Options:
A. 0.25 s
B. 2.5 s
C. 25 s
D. 250 s
ANSWER: B
, 4
Verified Solution: Accumulated value × time base = 250 × 0.01 s = 2.5 s elapsed.
Q008: A motor control center (MCC) bucket contains a size 3 reversing contactor.
The mechanical interlock fails. Which consequence is most likely?
Options:
A. Coil burnout on both contactors
B. Short-circuit between line phases if both close
C. Motor runs in forward only
D. Overload relay nuisance trips
ANSWER: B
Verified Solution: Without interlock, both contactors can close simultaneously,
creating a phase-to-phase short across the line.
Q009: A VFD is programmed for 2-wire control, source mode. The run command
is wired to a maintained contact. The motor will not start. Voltage at run terminal is
0 V when contact is closed. Which fault exists?
Options:
A. Contact is wired to sink mode terminal
B. Analog speed reference is missing
C. DC injection braking is enabled
D. Motor thermistor is open
ANSWER: A
Verified Solution: Source mode expects +24 V on run terminal; wiring to sink
terminal keeps terminal at 0 V—no start command.
Q010: A 480 V motor branch circuit uses a 100 A inverse-time breaker and 100 A
fuses in series for backup protection. Which NEC section prohibits this
arrangement?
Options:
