NATE Exam Core Essentials Flashcards
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Questions and Answers

What is the resistance of a circuit that has a voltage of 10 V and a current of 5 A?

  • 20 Ω
  • 15 Ω
  • 2 Ω (correct)
  • 50 Ω

    • The total resistance of a series circuit is equal to the ____.

    sum of all the resistances in the circuit

    The total current in a parallel circuit is ____.

    the sum of the currents through the individual paths

    The rate of doing work is called ____.

    <p>power</p> Signup and view all the answers

    One kilowatt is equal to ____.

    <p>1,000 W</p> Signup and view all the answers

    Which of the following equations is used to solve for electric power?

    <p>All of the above</p> Signup and view all the answers

    What is the power in a circuit that has a current of 10 A and a resistance of 10Ω?

    <p>1 kW</p> Signup and view all the answers

    The voltage induced in each turn of the secondary coil of a transformer is ____.

    <p>the same as the voltage induced per turn of the primary coil</p> Signup and view all the answers

    The load rating of a transformer is stated in ____.

    <p>volt-amperes</p> Signup and view all the answers

    An AC induction motor consists of a stationary part called the ____ and a rotating part called the ____.

    <p>stator, rotor</p> Signup and view all the answers

    What is the synchronous speed of a three-phase motor that has six poles and is operated on a 60-Hz alternating current?

    <p>1,200 RPM</p> Signup and view all the answers

    How does the power factor of an inductive motor affect efficiency?

    <p>The lower the power factor, the less efficient the motor is</p> Signup and view all the answers

    Which of the following single-phase AC motors does not have a start winding?

    <p>Shaded-pole</p> Signup and view all the answers

    A centrifugal switch opens the start winding circuit when a capacitor-start motor reaches approximately ____% of its full speed.

    <p>75 to 80%</p> Signup and view all the answers

    A run capacitor is always connected to the ____ and ____ terminals.

    <p>start, run</p> Signup and view all the answers

    Terminal No. 1 on all potential relays is always connected to the ____.

    <p>start capacitor</p> Signup and view all the answers

    The coil of a voltage relay is between terminal ____ and terminal ____ of the relay.

    <p>2, 5</p> Signup and view all the answers

    What type of AC motor has the highest starting torque and the greatest efficiency?

    <p>Three-phase</p> Signup and view all the answers

    How many terminals does a dual-voltage three-phase motor have?

    <p>9</p> Signup and view all the answers

    The primary function of any wiring diagram is to ____.

    <p>aid the technician in finding the problem</p> Signup and view all the answers

    How many functions is an individual circuit in a control system designed to control?

    <p>One</p> Signup and view all the answers

    The ability to utilize all types of communication skills is ____ to the HVACR technician.

    <p>Very important</p> Signup and view all the answers

    It is important to be ____ in filling out service orders so that office staff, other technicians, and customers will know what work you completed on the job.

    <p>All of the above</p> Signup and view all the answers

    When explaining to a customer that you have adjusted the system charge, which of the following terms is most appropriate?

    <p>Refrigerant</p> Signup and view all the answers

    Listening carefully to what a customer is telling you ____.

    <p>Can help you diagnose the problem</p> Signup and view all the answers

    When you arrive at a service call and meet the customer, you should ____.

    <p>Listen to the customer first, then ask questions</p> Signup and view all the answers

    What is the volume of a room that measures 10 ft by 20 ft with an 8-ft ceiling?

    <p>1,600 ft3</p> Signup and view all the answers

    What is the CFM requirement for an 1,800-ft2 house with 8-ft ceilings, if five air changes per hour are needed?

    <p>1,200 CFM</p> Signup and view all the answers

    What is the CFM requirement for an 2,400-ft2 house with 8-ft ceilings, if five air changes per hour are needed?

    <p>1,600 CFM</p> Signup and view all the answers

    What is the cross-sectional area of a 10-in round metal duct?

    <p>79 in2</p> Signup and view all the answers

    How fast does air with a velocity pressure of 0.20 in.w.g. move through a round duct?

    <p>1,800 ft/min</p> Signup and view all the answers

    How fast does air with a velocity pressure of 0.20 in w.g. move through a square duct?

    <p>1,800 ft/min</p> Signup and view all the answers

    Customers depend on you to be ____.

    <p>All of the above</p> Signup and view all the answers

    Before leaving a service call, you should be sure to ____.

    <p>Demonstrate system operation and describe basic maintenance procedures to the customer</p> Signup and view all the answers

    What is the advantage of using a tube cutter to cut copper pipe?

    <p>All of the above</p> Signup and view all the answers

    Spring-type benders may be used on ____.

    <p>Soft drawn copper</p> Signup and view all the answers

    A flaring tool is used to ____.

    <p>Make a mechanical joint in tubing</p> Signup and view all the answers

    A swaging tool is used to ____.

    <p>Solder tubing without the use of couplings</p> Signup and view all the answers

    What is one of the advantages of a glass-stem thermometer?

    <p>It is very accurate</p> Signup and view all the answers

    In discussing human comfort, the temperature most commonly referred to is ____.

    <p>Dry-bulb</p> Signup and view all the answers

    A sling psychrometer uses two glass-stem thermometers. One measures dry-bulb, and the other measures ____.

    <p>Wet-bulb</p> Signup and view all the answers

    A standard refrigeration manifold uses what type of element to measure pressure?

    <p>Bourdon tube</p> Signup and view all the answers

    What is the pressure range of a standard compound gauge on a refrigerant manifold?

    <p>30 in.Hg to 350 psig</p> Signup and view all the answers

    What is the best tool for removing moisture and non-condensibles from a system before adding refrigerant?

    <p>Vacuum pump</p> Signup and view all the answers

    A vacuum gauge reads pressure in ____.

    <p>Microns</p> Signup and view all the answers

    Which of the following is not a method of leak detection?

    <p>Micronic</p> Signup and view all the answers

    To prevent the release of refrigerant to the atmosphere while removing it from a system, what type of equipment must be used?

    <p>Recovery machine</p> Signup and view all the answers

    An anemometer uses a small fan blade to measure ____.

    <p>Air velocity</p> Signup and view all the answers

    What is one of the advantages of using silver brazing rods for copper-to-copper joints?

    <p>No flux is required</p> Signup and view all the answers

    "Housekeeping" includes ____.

    <p>All of the above</p> Signup and view all the answers

    What type of eye protection should you wear when drilling overhead?

    <p>Goggles</p> Signup and view all the answers

    What agency regulates cylinders and chemicals transported in a service vehicle?

    <p>DOT</p> Signup and view all the answers

    Material safety data sheets ____.

    <p>Contain information about personal protective equipment</p> Signup and view all the answers

    When should oxygen be used in a refrigeration system?

    <p>Never</p> Signup and view all the answers

    Which of the following classifications of fire extinguishers should be used for electrical fires?

    <p>C</p> Signup and view all the answers

    Which of the following categories could be considered a hazardous atmosphere in a confined space?

    <p>All of the above</p> Signup and view all the answers

    Which of the following best describes an asphyxiating atmosphere?

    <p>Low oxygen level</p> Signup and view all the answers

    If a ladder is placed against a wall that is 20 ft tall, what is the proper distance away from the wall for the base of the ladder?

    <p>5 ft</p> Signup and view all the answers

    When using a ladder, you should always ____.

    <p>Maintain three points of contact</p> Signup and view all the answers

    What is one of the most important safety precautions that you can take when working on electrical equipment?

    <p>Disconnect and lock out power before starting unless testing requires the power to be on</p> Signup and view all the answers

    When does a ground fault circuit interrupter open an electric circuit?

    <p>When current travels through a ground path other than the neutral</p> Signup and view all the answers

    Proper lockout/tagout procedures state that locks placed on a lockout device may be removed ____.

    <p>Only by the person who installed the locks</p> Signup and view all the answers

    A natural cooling process produced by moisture on the skin changing to low-pressure steam is called ____.

    <p>Evaporation</p> Signup and view all the answers

    During the heating season, human comfort can be enhanced without changing the temperature of the air by ____.

    <p>Adding moisture</p> Signup and view all the answers

    During the cooling season, dampers on bypass humidifiers should be ____.

    <p>Completely closed</p> Signup and view all the answers

    All matter can exist as a ____.

    <p>All of the above</p> Signup and view all the answers

    Stored energy is called ____ energy.

    <p>Potential</p> Signup and view all the answers

    Heat that you can feel and measure directly with a thermometer is called ____ heat.

    <p>Sensible</p> Signup and view all the answers

    The heat energy change associated with a phase (state) change is called ____ heat.

    <p>Latent</p> Signup and view all the answers

    The amount of heat (Btu) needed to raise the temperature of 1 lb of a substance 1°F is called the ____ heat of the substance.

    <p>Specific</p> Signup and view all the answers

    The latent heat of fusion is the amount of energy required to change 1 lb of a substance from the ____ phase to the ____ phase without changing its temperature.

    <p>Liquid, solid</p> Signup and view all the answers

    At 32°F, 1 lb of ice can be changed to 1 lb of water by adding ____ Btu.

    <p>144 Btu</p> Signup and view all the answers

    At 212°F, 1 lb of water can be changed to 1 lb of steam by adding ____ Btu.

    <p>970 Btu</p> Signup and view all the answers

    When liquid and vapor phases of a substance exist together, and no more liquid can vaporize without more energy being added, the vapor is said to be ____.

    <p>Saturated</p> Signup and view all the answers

    When a vapor is heated to a temperature higher than its saturation point, both the added heat and the temperature above saturation are called ____.

    <p>Superheat</p> Signup and view all the answers

    The process of molecules escaping from the surface of a liquid is called ____.

    <p>Evaporation</p> Signup and view all the answers

    The process of a solid turning directly into a vapor without going through the liquid state is called ____.

    <p>Sublimation</p> Signup and view all the answers

    The continuous movement of molecules within a liquid or gas is called ____ energy.

    <p>Kinetic</p> Signup and view all the answers

    Enthalpy includes both ____ and ____ heat energy.

    <p>Latent, sensible</p> Signup and view all the answers

    The measurement of the force that gravity exerts is called ____.

    <p>Weight</p> Signup and view all the answers

    The amount of matter in a substance is called ____.

    <p>Mass</p> Signup and view all the answers

    Weight per unit volume or mass per unit of volume is called ____.

    <p>Density</p> Signup and view all the answers

    Volume per unit of mass or weight is called ____.

    <p>Specific volume</p> Signup and view all the answers

    Under standard conditions, air weighs approximately ____ lb/ft3.

    <p>0.075 lb/ft3</p> Signup and view all the answers

    Solve to find the Fahrenheit temperature corresponding to 30°C.

    <p>86°</p> Signup and view all the answers

    Solve to find the Fahrenheit temperature corresponding to 20°C.

    <p>68°</p> Signup and view all the answers

    Solve to find the Celsius temperature corresponding to 80°F.

    <p>26.7°C</p> Signup and view all the answers

    Solve to find the Celsius temperature corresponding to 60°F.

    <p>15.6°C</p> Signup and view all the answers

    If the absolute temperature of a gas is doubled, under constant pressure the volume will be ____.

    <p>Doubled</p> Signup and view all the answers

    What is the new volume of 1 ft3 of air at 0°F when heated to 100°F?

    <p>1.2 ft3</p> Signup and view all the answers

    If gauge pressure reads 30 psi, what is the corresponding absolute pressure?

    <p>44.7 psia</p> Signup and view all the answers

    The law that applies to the total pressure exerted by a mixture of gases or vapors is called ____ Law.

    <p>Dalton's</p> Signup and view all the answers

    A coulomb is a charge of ____ electrons.

    <p>6.28 x 10^18</p> Signup and view all the answers

    An ampere is a measurement of ____.

    <p>Electron flow</p> Signup and view all the answers

    Voltage is best described as the ____.

    <p>Force that moves electrons through a circuit</p> Signup and view all the answers

    Current in a circuit is limited by ____.

    <p>Resistance</p> Signup and view all the answers

    A substance that permits the free movement of electrons is called a(n) ____.

    <p>Conductor</p> Signup and view all the answers

    Which of the following conductors would have the least resistance?

    <p>A short, large-diameter conductor</p> Signup and view all the answers

    If the voltage in a circuit is doubled and the resistance remains the same, the current will ____.

    <p>Double</p> Signup and view all the answers

    What is the voltage of a circuit if the resistance is 5Ω and the current is 5 A?

    <p>25 V</p> Signup and view all the answers

    Study Notes

    Communication Skills in HVACR

    • Effective communication is essential for HVACR technicians to convey information to customers and colleagues.
    • Clear, complete, and concise communication fills service orders, enhancing understanding among staff and clients.

    Technical Terminology

    • Use the term "Refrigerant" when discussing system charges; avoid colloquial terms like "Freon" or "juice."

    Customer Interaction

    • Actively listen to customers as it aids in diagnosing issues.
    • Prioritize listening before asking questions when meeting customers at service calls.

    Calculating Volume and Airflow

    • Volume for a room measuring 10 ft by 20 ft with an 8-ft ceiling is 1,600 ft³.
    • CFM (Cubic Feet per Minute) requirements can be calculated for homes based on area and air changes per hour.

    Duct and Air Velocity Calculations

    • The cross-sectional area of a 10-in round metal duct is 79 in².
    • Air velocity in ducts can be calculated using the formula: Velocity = 4005 x √(velocity pressure).

    Customer Service Attributes

    • Technicians must be honest, loyal, and patient to build trust with customers.
    • Importance of demonstrating system operations and maintenance procedures before leaving a service call.

    Tools and Equipment

    • Tube cutters provide clean cuts without metal shavings, suitable for both hard and soft drawn copper.
    • A variety of tools like flaring and swaging tools are essential for specific tasks in tubing and piping.

    Safety and Equipment Handling

    • Goggles are necessary for eye protection when drilling overhead.
    • Use recovery machines to avoid releasing refrigerants into the atmosphere during equipment maintenance.

    Pressure and Temperature Measurements

    • Standard refrigeration manifold gauges operate from 30 in.Hg to 350 psig.
    • Use vacuum gauges to measure pressure in microns when purging systems.

    Human Comfort Processes

    • Understanding dry-bulb and wet-bulb temperatures are critical for discussing human comfort.
    • Humidity levels are important in maintaining comfort; adding moisture enhances comfort during heating seasons.

    Fire Safety Guidelines

    • Fire extinguishers are classified by types, with Class C specifically for electrical fires.
    • Understanding hazardous atmospheres and safety protocols prior to confined space work is crucial.

    Electrical Concepts

    • Voltage, current, and resistance are foundational concepts in electrical work, following Ohm's Law (V = I × R).
    • Power calculations can be achieved using multiple formulas (e.g., P = VI, P = I²R).

    Thermal and Material Properties

    • Understanding latent vs. sensible heat is essential for HVAC calculations and applications.
    • The latent heat of fusion and vaporization are important for evaluating thermal energy in HVAC systems.

    Matter and Energy

    • All matter exists in three states: solid, liquid, and gas; understanding this is fundamental in HVAC and refrigerant management.
    • Density and specific volume are significant in assessing material characteristics, particularly in air handling and refrigeration contexts.

    Temperature Conversion

    • Familiarize with conversions between Celsius and Fahrenheit, key for various HVAC applications.

    Gaseous Behavior

    • The relationship between temperature, volume, and pressure in gases follows Charles’s Law; understanding this is vital for system efficiency calculations.

    Advanced Electrical Concepts

    • Familiarity with terms like coulomb and ampere aids in understanding electric charge and flow.
    • Technologies involving inductors, transformers, and electrical circuits necessitate a sound understanding of basic electrical principles.### Transformer Basics
    • The ratio of turns between the primary and secondary coils determines the transformer’s voltage conversion.

    Transformer Load Rating

    • Load rating of a transformer is expressed in volt-amperes (VA).

    AC Induction Motor

    • An AC induction motor has two main parts:
      • Stator: the stationary part
      • Rotor: the rotating part.

    Synchronous Speed

    • For a three-phase motor with six poles operating on a 60-Hz AC source, the synchronous speed is 1,200 RPM.

    Power Factor

    • The power factor of an inductive motor directly influences its efficiency:
      • A lower power factor indicates reduced operational efficiency.

    Single-Phase AC Motors

    • The shaded-pole motor is a type of single-phase AC motor that does not have a start winding.

    Centrifugal Switch in Motors

    • In capacitor-start motors, a centrifugal switch opens the starting winding circuit at approximately 75 to 80% of full speed.

    Run Capacitors

    • A run capacitor is permanently connected to both the start and run terminals within a motor.

    Potential Relays

    • In potential relays, terminal No. 1 is permanently linked to the start capacitor, while terminal No. 2 connects to the start winding of the motor.

    Voltage Relay Coil Terminals

    • The coil of a voltage relay is positioned between terminal 2 and terminal 5 of the relay.

    Motor Types

    • The three-phase motor exhibits the highest starting torque and efficiency compared to other AC motors.

    Dual-Voltage Motors

    • A dual-voltage three-phase motor features a total of nine terminals.

    Wiring Diagrams

    • The primary purpose of a wiring diagram is to assist technicians in identifying and troubleshooting problems efficiently.

    Control System Circuits

    • Each circuit within a control system is designed to regulate one specific function.

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    Test your knowledge of essential HVACR communication skills with these flashcards designed for the NATE exam. Each card challenges you to identify the correct answers related to the importance of communication in the field. Perfect for those preparing for the NATE certification.

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