SACA C-202 Electric Motor Control Systems –
Comprehensive Study Guide
Module 1: Safety, Codes, and Electrical Fundamentals
1. Equipment grounding involves connecting to earth ground all _____ parts of an
electrical system that do not carry current under normal conditions. - ANSWER
Metallic
2. A current as small as _____ can be fatal. - ANSWER 100 mA
3. _____ stands for National Electrical Code. - ANSWER NEC
4. Standing on a wet floor _____ the resistance between you and ground, increasing
the possibility of severe shock. - ANSWER Decreases
5. _____ is the process of blocking the energy flow from a power source to a piece
of equipment and assuring it remains blocked. - ANSWER Lockout
6. An alternator has three main windings that are placed _______ degrees apart. -
ANSWER 120
7. A ___ configured distribution system has one end of each phase winding
connected together. - ANSWER WYE
8. A(n) _____ configured distribution system has each phase winding connected
end-to-end to form a loop. - ANSWER DELTA
9. A(n) _____ is a conductor that provides a return path to the source for the current
carrying conductors in the system. - ANSWER Neutral
10. When one of the phases of a system becomes grounded, it is called a _____. -
ANSWER Ground Fault
11. The two most common devices to disconnect power to a circuit are a _____ and
a circuit breaker. - ANSWER Fusible Disconnect
12. A _____ fuse has two elements, an instantaneous element and an overload
element. - ANSWER Time-Delay
, 13. _____ current is the current that is drawn by a motor when it is operating at its
rated operating speed. - ANSWER Full-Load
14. _____ is the maximum current carrying capacity of a conductor. - ANSWER
Ampacity
15. Typically, the overcurrent protection for a motor should be selected for
_________ % of the full-load current of the motor. - ANSWER 125
16. The _____ of a three-phase motor is made up of three separate sets of
windings. - ANSWER Stator
17. One of the most common NEMA frame sizes for small motors is _____. -
ANSWER 56
18. _____ is the temperature of the air surrounding an operating motor. - ANSWER
Ambient Temperature
19. Which law states that the voltage induced in a coil is proportional to the rate
of change of magnetic flux? - ANSWER Faraday's Law
20. The term "slip" in an induction motor refers to: - ANSWER The percentage
difference between synchronous speed and rotor speed
21. A motor nameplate indicates "NEMA Design B". This means the motor is: -
ANSWER Standard 3-phase, 4-pole, 1800 RPM (or 1725 RPM)
22. Before performing maintenance on a motor control system, the first step is: -
ANSWER Lockout/tagout the circuit
Module 2: Motor Control Components and Devices
23. What is the primary function of a contactor in an electric motor control
circuit? - ANSWER A contactor is used to establish or interrupt the flow of electrical
current to the motor by closing or opening the circuit, typically in combination with
overload protection to safely control large motors in industrial applications.
24. What is the purpose of an overload relay in a motor control circuit? - ANSWER
An overload relay protects the motor from damage caused by excessive current or
overheating. It senses the motor's current and trips the circuit if the current exceeds the
rated value, thereby preventing potential motor damage.
Comprehensive Study Guide
Module 1: Safety, Codes, and Electrical Fundamentals
1. Equipment grounding involves connecting to earth ground all _____ parts of an
electrical system that do not carry current under normal conditions. - ANSWER
Metallic
2. A current as small as _____ can be fatal. - ANSWER 100 mA
3. _____ stands for National Electrical Code. - ANSWER NEC
4. Standing on a wet floor _____ the resistance between you and ground, increasing
the possibility of severe shock. - ANSWER Decreases
5. _____ is the process of blocking the energy flow from a power source to a piece
of equipment and assuring it remains blocked. - ANSWER Lockout
6. An alternator has three main windings that are placed _______ degrees apart. -
ANSWER 120
7. A ___ configured distribution system has one end of each phase winding
connected together. - ANSWER WYE
8. A(n) _____ configured distribution system has each phase winding connected
end-to-end to form a loop. - ANSWER DELTA
9. A(n) _____ is a conductor that provides a return path to the source for the current
carrying conductors in the system. - ANSWER Neutral
10. When one of the phases of a system becomes grounded, it is called a _____. -
ANSWER Ground Fault
11. The two most common devices to disconnect power to a circuit are a _____ and
a circuit breaker. - ANSWER Fusible Disconnect
12. A _____ fuse has two elements, an instantaneous element and an overload
element. - ANSWER Time-Delay
, 13. _____ current is the current that is drawn by a motor when it is operating at its
rated operating speed. - ANSWER Full-Load
14. _____ is the maximum current carrying capacity of a conductor. - ANSWER
Ampacity
15. Typically, the overcurrent protection for a motor should be selected for
_________ % of the full-load current of the motor. - ANSWER 125
16. The _____ of a three-phase motor is made up of three separate sets of
windings. - ANSWER Stator
17. One of the most common NEMA frame sizes for small motors is _____. -
ANSWER 56
18. _____ is the temperature of the air surrounding an operating motor. - ANSWER
Ambient Temperature
19. Which law states that the voltage induced in a coil is proportional to the rate
of change of magnetic flux? - ANSWER Faraday's Law
20. The term "slip" in an induction motor refers to: - ANSWER The percentage
difference between synchronous speed and rotor speed
21. A motor nameplate indicates "NEMA Design B". This means the motor is: -
ANSWER Standard 3-phase, 4-pole, 1800 RPM (or 1725 RPM)
22. Before performing maintenance on a motor control system, the first step is: -
ANSWER Lockout/tagout the circuit
Module 2: Motor Control Components and Devices
23. What is the primary function of a contactor in an electric motor control
circuit? - ANSWER A contactor is used to establish or interrupt the flow of electrical
current to the motor by closing or opening the circuit, typically in combination with
overload protection to safely control large motors in industrial applications.
24. What is the purpose of an overload relay in a motor control circuit? - ANSWER
An overload relay protects the motor from damage caused by excessive current or
overheating. It senses the motor's current and trips the circuit if the current exceeds the
rated value, thereby preventing potential motor damage.
