Download SACA Study Guide Motor Control Exam. and more Exams Nursing in PDF only on Docsity!
SACA Study Guide Motor Control Exam.
Parts of an electrical system that should be connected to earth include _______. - CORRECT ANSWER All of the above The _______ is the accepting standard in the United States for safely installing and maintaining electrical systems and equipment. - CORRECT ANSWER NEC (National Electrical Code) Which of the following is not a basic rule of electrical safety? - CORRECT ANSWER Always work by yourself Who should remove a lockout/tagout? - CORRECT ANSWER Only the person(s) who installed it Three-phase power is transmitted in phases that are _______ degrees apart. - CORRECT ANSWER 120 Which of the following is not a common voltage supplied by a wye-configured system? - CORRECT ANSWER 240 VAC A grounded neutral wire can be used as an equipment ground. - CORRECT ANSWER False A ground fault occurs when __________. A. the ground conductor is opened B. one of the phases is opened C. one of the phases becomes grounded D. the system becomes unbalanced - CORRECT ANSWER One of the phases becomes ungrounded Which of the following is not a part of a fusible disconnect? - CORRECT ANSWER None of the above A time-delay fuse only has one element. - CORRECT ANSWER False
Which of the following is a factor that must be considered when selecting overcurrent protection devices for a motor control circuit? - CORRECT ANSWER Rated full-load current of the motor Which of the following is a typical three-phase squirrel-cage motor? - CORRECT ANSWER All of the above Which of the following items on a motor's nameplate is used to determine how much output power a motor can safely produce above its rated output power? - CORRECT ANSWER Service Factory If the service factor for a motor is not given on the nameplate, what should you assume the service factor to be? - CORRECT ANSWER 1 Which of the following is not a result of connecting a dual-voltage motor to operate on the higher voltage? - CORRECT ANSWER Increased current draw Which of the following is not a function of motor control? - CORRECT ANSWER None of the above Which of the following is not a basic requirement for a typical motor installation? - CORRECT ANSWER All of the above A motor starter is the same as a motor controller. - CORRECT ANSWER False Magnetic contactors open and close their contacts through the use of a magnetic coil. - CORRECT ANSWER True The type of manual starter used for three-phase motors is a ________. - CORRECT ANSWER Integral horsepower starter The contacts of a manual starter will remain in the actuated position when power is lost. - CORRECT ANSWER True
To avoid running separate lines to a machine for power devices and control devices, the higher voltage required by the power devices can be produced by using a control transformer to step up the control voltage. - CORRECT ANSWER False To get a control voltage of 120 VAC from a control transformer if the line voltage is 240 VAC, the primaried must be connected in series. - CORRECT ANSWER False To get a control voltage of 120 VAC from a dual-voltage control transformer if the line voltage is 480 VAC, the primaries must be connected in series. - CORRECT ANSWER True When checking a transformer with an ohmmeter, which of the following can you check for? - CORRECT ANSWER All of the above Transformers are rated in units called Volt-Amperes (VA). - CORRECT ANSWER True The NEC requires that for an output voltage to be higher than 50 VAC one side of a control transformer secondary be connected to ground or both sides of the secondary must be fused. - CORRECT ANSWER True When a control transformer is used, NEC requires that both sides of the secondary must be connected to earth ground. - CORRECT ANSWER False A control relay is designed to switch components on and off only when it receives a manual input. - CORRECT ANSWER False Which of the following is an application of a control relay? - CORRECT ANSWER All of the above When a relay is connected so that it continues to energize itself after a momentary input is removed, the circuit is called a _______. - CORRECT ANSWER Seal-in circuit General-purpose relays are designed for light-duty industrial applications. - CORRECT ANSWER True
Machine control relays are designed for light-duty industrial applications. - CORRECT ANSWER False _______ is a method of representing one component with several symbols in various locations on a ladder diagram. - CORRECT ANSWER Detached symbology Control relays are not capable of performing memory logic by themselves. - CORRECT ANSWER True One method of deenergizing a seal-in circuit is with a stop pushbutton. - CORRECT ANSWER True The minimum number of sets of contacts a motor starter has depends on the number of power leads the motor requires. - CORRECT ANSWER True Which of the following is a component of a magnetic motor starter? - CORRECT ANSWER All of the above Two-wire control circuits provide low-voltage protection. - CORRECT ANSWER False Which of the following is not a typical input device used for two-wire control circuits? - CORRECT ANSWER Pushbutton switch A three-wire control circuit is not as safe as a two-wire control circuit. - CORRECT ANSWER False Three-wire control circuits are commonly used for start/stop pushbutton stations. - CORRECT ANSWER True A push-to-test pilot light allows the operator to test the indicator bulb to make sure it works. - CORRECT ANSWER True A push-to-test light is exactly the same as a regular indicator lamp, except it has a special color lens. - CORRECT ANSWER False
Which of the following statements is not true of AND logic? - CORRECT ANSWER In an AND logic circuit, only one of the inputs must be activated to energize the output An OR logic circuit is formed by 2 or more N.O. Switches in parallel. - CORRECT ANSWER True Which of the following statements is true on NOT logic? - CORRECT ANSWER All of the above NOR logic is formed by 2 or more N.C. switches in parallel. - CORRECT ANSWER False NAND logic is formed by 2 or more N.O. Switches in parallel. - CORRECT ANSWER False Troubleshooting is the process of finding the cause of a machine malfunction. - CORRECT ANSWER This is also known as a fault Most troubleshooters in manufacturing plants perform component level testing. - CORRECT ANSWER False The process of finding the cause of a machine malfunction is called fault hunting. - CORRECT ANSWER False Which of the following is a method of testing a component? - CORRECT ANSWER All of the above To determine if an indicator lamp has failed, measure the lamp's _______. - CORRECT ANSWER Resistance If none of the contacts of a manual switch charge status when the operator is activated, what is the most probable cause? - CORRECT ANSWER Mechanical problem with the operator To test a relay coil out-of-circuit, you would measure _______. - CORRECT ANSWER Resistance
Which of the following is not a possible cause when none of the contacts on a motor contactor change status when the coil is energized? - CORRECT ANSWER None of the above One possible cause for an overload to trip consistently is that the trip setting is incorrect (IEC) or the incorrect heater size is being used (NEMA). - CORRECT ANSWER True Resistance readings across the windings of a motor should be very high. - CORRECT ANSWER False Which of the following is a possible cause for a motor to overheat? - CORRECT ANSWER All of the above Parts of an electrical system that should be connected to earth ground include _______. - CORRECT ANSWER All of the above A(n)_______ is a device that can be used to measure several different electrical characteristics. - CORRECT ANSWER DMM The IEC developed a standard to rate DMMs based on the maximum voltage spike the meter can withstand without causing an arc. - CORRECT ANSWER True The _______ is the accepted standard in the United States for safely installing and maintaining electrical systems and equipment. - CORRECT ANSWER NEC There is no need to change voltage range on a wiggy. - CORRECT ANSWER True Which of the following is not a basic rule of electrical safety? - CORRECT ANSWER Always work by yourself Who should remove a lockout/tagout? - CORRECT ANSWER Only the person(s) who installed it A circuit must be disconnected to use a clamp-on ammeter to measure the circuit. - CORRECT ANSWER False
Which of the following is a factor that must be considered when selecting overcurrent protection devices for a motor control circuit? - CORRECT ANSWER Rated full-load current of the motor Which of the following is a type of in-circuit component test? - CORRECT ANSWER All of the above If a relay coil is good, you should get no voltage reading across it when it is energized. - CORRECT ANSWER False Which of the following is a component of a typical three-phase squirrel-cage motor? - CORRECT ANSWER All of the above Which of the test probes placed in the circuit as shown in the figure, what should the voltage reading be if the start pushbuttons pressed, assuming the circuit is operating properly? - CORRECT ANSWER Full control voltage Which of the following items on a motor's nameplate is used to determine how much output power a motor can safely produce above its rated power? - CORRECT ANSWER Service Factor If the service factor for a motor is not given on the nameplate, what should you assume the service factor to be? - CORRECT ANSWER 1 Which of the following is not a result of connecting a dual-voltage motor to operate on the higher voltage? - CORRECT ANSWER Increased current draw You can reverse the rotation of any three-phase motor by interchanging any two of the three power supply lines. - CORRECT ANSWER True A reversing magnetic motor starter provides a magnetic method of changing a motor's direction of rotation. - CORRECT ANSWER True Based on the wiring diagram shown, which of the following statements is true of a drum switch if the switch is placed in the reverse position? - CORRECT ANSWER L1 is connected to T3, L2 is connected to T2, and L3 is connected to T
Which of the following is a component of a reversing magnetic motor starter? - CORRECT ANSWER All of the above One application of the interlocking is to cause both the forward and reverse coils of a reversing contactor to be energized at the same time. - CORRECT ANSWER False Examine the circuit shown and determine which type(s) of interlocking is/are shown. - CORRECT ANSWER Auxiliary contact and mechanical interlocking Mechanical interlocking should be should be used in combination with one of the electrical methods so that the locked coil cannot be energized. - CORRECT ANSWER True A _______ is often used to allow an operator or technician to change a machine from the automatic mode to the manual mode. - CORRECT ANSWER Selector switch Based on the circuit shown, what will happen ti the motor if the JOG pushbutton is pressed? - CORRECT ANSWER The motor will run until the JOG button is released A Hand-Off_Automatic (H-O-A) circuit requires a selector switch with _______ positions. - CORRECT ANSWER 3 Because of the versatility and efficiency, most of the power produced and transmitted throughout the world is three-phase - CORRECT ANSWER True Power Companies transmit three-phase power at a very high voltage to minimize power losses. - CORRECT ANSWER A distribution system reduces the power to lower voltages using transformers at a substation or or at the plant site A control relay is designed to switch - CORRECT ANSWER True
