Term
| Three reference points for checking temperature measuring instruments are....... |
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Definition
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Term
| To check the temperature leads of an electronic thermometer for low temperature, they should be stirred in a container of..... |
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Definition
| Crushed ice and pure water |
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Term
| To check the temperature leads of an electronic thermometer for high temperature, they should be....... |
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Definition
| suspended in a pan of voiling water |
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Term
| if the ammeter is off by more than _____% it should be sent to the repair shop |
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Definition
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Term
| The _____ is used most freqently for amperage checks |
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Definition
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Term
| Ohms law is representd with the formula _____ |
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Definition
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Term
| A device commonly used for detecting refrigerent leaks is a |
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Definition
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Term
| _____ can detect leak rates of about 1.4 oz per year |
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Definition
| electronic leak detectors |
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Term
| a flue gas analysist kit contains _______ |
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Definition
| co2 tester, draft guage, and a flue gas thermometer |
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Term
| ______ means the changing of the instruments output or reading to correspond to a standard or correct reading |
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Definition
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Term
| What type of charge does an electron have? |
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Definition
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Term
| if five electron combine with three proton, the net charge will be |
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Definition
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Term
| what part of an atom moves from one atom to another |
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Definition
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Term
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Definition
| glass, rubber, and plastic |
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Term
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Definition
| a measure of the quantity of electron flowing past a point in the electrical circuit in a given time |
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Term
| if two light bulbs are wired in series and one bulb burns out, the other bulb will______ |
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Definition
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Term
| An element in an electric heating unit is applied to a 232 volt power supply. the current flowing through the element it 19 amps. What is the resistance of the element? |
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Definition
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Term
| as loads are added in a paralell circuit, the total resistance of the circuit _____ |
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Definition
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Term
| to find the watts of electrical power in an electrical circuit, you multiply |
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Definition
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Term
| if a conductor carrying electrical current is formed into a coil, the magnetic feild around the wire will |
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Definition
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Term
| the automatic control of a system is intended to |
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Definition
| maintain stable or constant conditions with a controllable device |
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Term
| Modulating Controls are used to |
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Definition
| vary the speed of the motor |
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Term
| when a control is required to control a pace o product temperature, it is called a |
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Definition
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Term
| thermal system overload may occur if specific electrical or mechanical component is not is not cooled poperly, resulting in |
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Definition
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Term
| The control that stops the condensing unit if the head pressure climbs to high is classified as a |
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Definition
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Term
| the overload device mounted on the compressor terminal box would be classified as a |
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Definition
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Term
| the metals most commonly used in a bimetal temperature control are |
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Definition
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Term
| an example of a bimetal device is a |
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Definition
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Term
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Definition
| tends to straigthen out with and increase in vapor pressure |
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Term
| a termocouple is a device that |
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Definition
| converts heat to electrical energy |
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Term
| the purpose of the heat anticipator is to |
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Definition
| reduce the temperatur swing of a conditioned space |
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Term
| the difference between system overshoot and system lag is called |
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Definition
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Term
| what is meant by the term "detent"? |
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Definition
| rapid making and breaking of a contact |
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Term
| the heat anticipator in the thermostat control circuit in the heating mode is active when |
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Definition
| heating contact is closed |
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Term
| the ______ must determine what the current flow is through the heating control circuit |
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Definition
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Term
| the cold anticipator is wired in _____ with the mercury bulb cooling contact and is energized during the off cycle. |
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Definition
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Term
| Line voltage themostats have heavier contacts and use which type of sensing elerment |
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Definition
| bimetal, bellows and remote bubl |
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Term
| to obtain an accurate reading of a fluid in a large pipe a techician should |
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Definition
| use a permanently mounted thermometer in a well |
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Term
| a low pressure control has a high event and a differential setting. the technician wants the system to turn on at 28 psig and shut down at 2 psig. what would be the proper settings |
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Definition
| high event 28 psig, differential 26 psig |
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Term
| if the suction pressure of a system is 60 psig and the oil pump outlet is 85 psig, what is the net oil pressure? |
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Definition
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Term
| Oil pressure safety controls measure the difference in pressure to establish |
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Definition
| that positive oil pressure is present |
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Term
| to control ice build-up on a heat pump outdoor coil in the heating cycle, a ____ is attached to a large diaphragm |
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Definition
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Term
| where would a water regulating valve that is controlling head pressure be installed? |
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Definition
| water circuit at the inlet of condenser |
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Term
a control can be which of the following
electrical
mechanical
electrical and mechanical
All of the above |
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Definition
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Term
| an example of a power consuming device would be a ______ while and example of a non power consuming device would be a _______ |
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Definition
| Light Bulb, single pull single throw switch |
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Term
| an electrical power consuming component _____ |
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Definition
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Term
| the line side of a switch is the |
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Definition
| side the power source is connected to |
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Term
| if an air conditioning system is calling for cooling and the compressor is running but the indoor fan is not running, which terminal on the termostat will the technician most likley to check first? |
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Definition
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Term
| the _____ is nothing more than a set of switches |
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Definition
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Term
| the continuity through a heat relay is checked using a |
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Definition
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Term
| a 10 wrap amerage multiplier is used with a |
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Definition
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Term
| transformers are rated using ____ |
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Definition
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Term
| A _____ is the easiest diagram to use to follow a circuit. this diagram normally can be studied briefly, and the circuit function should become obvious |
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Definition
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Term
| an electrical diagram showing the approximate location of the components is called a |
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Definition
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Term
| a ____ reacts to stop, start or modulate flow of water, air, air or refirgerent to the system conditioned space |
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Definition
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Term
| all control systems can be subdivided into _____, no matter how many controls there are |
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Definition
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Term
| _____ control systems were used before electronics |
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Definition
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Term
| Pnumatic controls must have a permanent air supply that is |
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Definition
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Term
| in most system compressors, the compressors are controlled with a ______ |
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Definition
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Term
| a ___ is either in the pressure reducer or in the downstream side of the system to ensure that the control air pressure does not exceed about 30 psig |
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Definition
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Term
| in a _____ loop, all changes happen within the system |
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Definition
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Term
| a device caled a ____ is used to control the large volume of air in a air conditioning system. |
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Definition
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Term
| the pilot positioner has a main air supply that is goverened by the _____ |
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Definition
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Term
| controlling the water flow to the rooms needs is called |
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Definition
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Term
| the temperature in the room is known as the ____ air temperature |
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Definition
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Term
| electronic controls are commonly called |
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Definition
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Term
| the controlled environment could be controlled by an array of _____ such as dampers, fans, variable-frequency drives |
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Definition
| controlled output devices |
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Term
| _____ usually housed internally inside the controller convert the information from either analog to digital or digital to analog format |
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Definition
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Term
| a motors speed is determined by the |
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Definition
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Term
| start windings are placed _______ with the run windings |
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Definition
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Term
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Definition
| more turns than the run windings |
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Term
| a split-phase has a _____ winding and a _____ winding |
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Definition
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Term
| when a general duty split-phase motor reaches approximatly 75% of its operating speed, the start winding is de-energized by a |
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Definition
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Term
| a split-phase motor that has a current relay and a start capacitor is called a ____ motor |
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Definition
| Capicitor Start, Induction Run (CSIR) |
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Term
| a perminent split capacitor (PSC) motor that is running and up to speed will have the start winding _____ |
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Definition
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Term
| when a CSCR moto initially starts, what is the total capacitence acting on the motor? (Run cap is 5 mfD and the start is 20 mfD) |
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Definition
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Term
| capacitors wird in series with the start winding provide _____ |
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Definition
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Term
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Definition
| has little starting torque |
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Term
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Definition
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Term
| the starting device usually used on a single phase, fractional horsepower motors requiring low starting torque is the |
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Definition
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Term
| the positive temperature coefficient resistor start device is a type of |
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Definition
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Term
which of the following voltages are not safe for a 208-V motor to operate?
a)170
b)220
c)238
Or A and C |
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Definition
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Term
| if the voltage supplied to the motor is well below the motor rated voltage, the current draw will be ______ it should be |
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Definition
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Term
| the voltage tolerance of a standard electric motor is ______ |
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Definition
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Term
| the locked rotor amperage is normally _____ times as great as the run load amperage |
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Definition
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Term
| why are explosion proof motors not normally used on standard equipment |
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Definition
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Term
| the motor that should be used ina potentially wet area is a ____ motor |
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Definition
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Term
| When referring to motors, to what does the "insulation class" relate? |
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Definition
| the normal operating temperature of the motor |
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Term
| a sleeve bearing would typically be used in a motor that operates with a |
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Definition
| light load and where noise is a factor |
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Term
| a slotted screw at the bottom of the bearing housing is called a |
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Definition
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Term
| a direct drive motor is usally connectd to a load with a |
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Definition
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Term
| grounding straps are required on a resilient mounted motors to |
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Definition
| ground the motor in case of winding failure |
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Term
| the width of a drive belt is clasified as |
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Definition
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Term
| the alignment of a motor and the driven mechanism must be done at room temperature and |
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Definition
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Term
| a common practice in condensing units is to use a contactor with only one set of contacts opening only one side of the power to the unit. This is to |
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Definition
| provide off cycle heat to the compressor |
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Term
| beside maintaining pressure on the contacts for current carrying capacity, the pressure springs have a second important function. This is to |
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Definition
| help obtain equal contact against the stationary contacts |
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Term
| when a contactors coil is energized, how much resistance should be measured between terminal "L1" and terminal "T1" |
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Definition
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Term
| Tech A says that if you take a voltage reading from terminal L1 to terminal T1 on a contactor whose coil is energized, you should read zero volts. Tech B says that contactors can only have normally open contacts. Which of tech is correct? |
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Definition
| Tech A is correct. Tech B is inncorrect |
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Term
| an inherent motor protector is a _____ |
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Definition
| thermally activated device in the motor windings |
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Term
| the service facctor of an electric motor is determined by the |
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Definition
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Term
| standards for motor overload protection are set by the |
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Definition
| NEC National Electrical Code |
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Term
| A solder pot is part of a |
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Definition
| resettable circuit breaker |
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Term
which of the following overload devices is not affected bu the ambiant temperature
solder pot
magnetic
bi-metal
time-delay fise |
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Definition
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Term
| most electrical problems with an electric motor are |
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Definition
| short circuited windings, open windings and grounded windings |
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Term
| a tech needs to check a single phase compressor. He labels the three terminals A, B and C and takes resistance readings of the windings. He reads 10 Ohms from A to B, infinity from B to C and Infinity from C to A. Identify the terminals |
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Definition
| Cannont Identify terminals, Open Windings |
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Term
| Tech A says that while checking the windings of a compressor, a reading of 10 ohms or less from the common terminal to ground indicates that the motor is okay. Tech B says that the resistance of the start winding should always be less than the resistance of the run winding. Which Tech is correct? |
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Definition
| Neither, they are both incorrect |
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Term
| an open winding in an electric motor means that |
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Definition
| a wire in a winding is broken |
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Term
Tech A syas that a shorted winding will result in an increased current flow through the winding. Tech B syas that if a motor is to be replaced, a motor with a lower horsepower rating should always be used.
Which Tech is correct? |
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Definition
| Tech A is correct, B is incorrect |
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Term
| if the resistance of the run winding decreases, the _____ |
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Definition
| motor will draw to much current while it is running |
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Term
| if a condenser fan motor grounds out it will usually |
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Definition
| trip a circuit breaker to shut off the unit |
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Term
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Definition
| measures very high resistances |
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Term
| if a motor hums but does not start, ther is a potental problem ______ |
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Definition
| with the starting components, with an open winding, or with insufficant supply voltage |
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Term
| the recommended way to discharge a capacitor is to ______ |
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Definition
| usa a 20K ohm 5 Watt resisor that has had insolated leads soldered to it |
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Term
| the wiring connectors that carry hte power to a motor must be in good condition. When a connection becomes loose, oxidation of the copper wire occure. The oxidation _______ |
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Definition
| acts as an electrical resistance and causes the connection to heat more |
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Term
| what is the best method to repair a fractional horsepower motor that has bad bearings? |
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Definition
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Term
| two common reasons for motor failure are improper puly alignment and |
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Definition
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Term
| a motor has four lease out of it, two red and two black. the resistane between the red leads is 3 ohms. the resistance between the black leads is 5 ohms. The black leads are connected to the _____ winding |
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Definition
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Term
| the leads of an ohmmeter using the R x 100 scale are placed on the terminals of a capacitor and then reversed. the needle does not move. This would indicate that the capacitor is |
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Definition
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Term
| if a normally operating motor draws 75 amos on start up, it will most likely draw _____ amps when running |
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Definition
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Term
| The most common material used on the surface of contacts is |
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Definition
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Term
| if a relay starts the indoor fan in the cooling mode of a central air-conditioning system, it must be able to withstand the ______ of the fan motor on start up |
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Definition
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Term
| the best way to repair a large contactor is by the replacement of the |
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Definition
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Term
| in order to be electrically safe, a motor that is set in a resilient mount must have a |
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Definition
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Term
| whenever possible, when changing a motor, the _________ should be obtained |
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Definition
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Term
| the device that transfers the motors energy to the driven component is called the |
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Definition
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Term
| the ______ is a winding that, when energized, will generate a magnetic feild as there will be current flowing through it |
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Definition
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Term
| The coil of a potential relay has ______ resistance |
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Definition
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Term
| the ______ system actually changes or conditions a signal in three steps |
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Definition
| DDC, Converts Conditions and Inverts |
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Term
| ________ is the part of the digital controller where the information is stored |
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Definition
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Term
| Electircal controls are devied into two catigories, power consuming and |
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Definition
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Term
| Non power consuming, or power passing, devices are commonly refered to as |
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Definition
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Term
| while checking a simple series 115v circuit containing a fuse, a switch and a light bulb, the voltmeter reads 115v across the light bulb socket. the light bulb us not on. The tech concludes that the ________ is defective |
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Definition
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Term
| one way to troubleshoot a ______ on a heating and cooling system is to first turn the fan selector switch to the FAN ON position and see if the fan starts |
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Definition
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Term
| Without ________ voltage, there is no low voltage |
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Definition
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Term
| the term used to describe when the temperature of a heated room rises above the thermostats set point is called |
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Definition
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Term
| the term used to describe when the temperature of a heated room falls below the thermostats set point is called |
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Definition
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Term
| the unit of measure for the current flow of electrical energy is the |
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Definition
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Term
| _______ are used to masure the intensity of current flow in a circuit or a particular branch in a circuit, so they are wired in series with the circuit being evaluated |
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Definition
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Term
| a transformer has 10,000 turns of wire in the secondary and 100 turns in the primary. the transformer is connected to a line voltage of 120V. the output voltage will be |
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Definition
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Term
| a solid state electical device that allows electrical energy to flow through only one direction is called a |
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Definition
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Term
| ______ means the changing of the instruments output or reading to correspond to a standard or correct reading |
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Definition
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Term
| _______ instruments measure the temperature of vapors, liquids and solids |
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Definition
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Term
| special thermometers are used to measure temperatures above ______ degrees F |
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Definition
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Term
| _________ instruments register presures above and below atmospheric pressure |
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Definition
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Term
| _______ points for all instruments should be established to give the technician confidence |
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Definition
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Term
| Any instrument with a digital readout will have _____ |
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Definition
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