Download SACA C-202 ELECTRIC MOTOR CONTROL SYSTEMS EXAM SCRIPT 2026 COMPREHENSIVE and more Exams Electrical Engineering in PDF only on Docsity!
SACA C-202 ELECTRIC MOTOR CONTROL
SYSTEMS EXAM SCRIPT 2026
COMPREHENSIVE
โ A(n) _____ serves as the control point for an SCR. Answer: gate โ A gate current is used to reduce the level of _____ voltage necessary for an SCR to conduct or fire. Answer: breakover โ _____ control is the control of the time relationship between two events when dealing with voltage and current. Answer: Phase โ _____ is one of the most suitable industrial applications of SCRs. Answer: DC motor control โ A(n) _____ is needed to properly test an SCR under operating conditions. Answer: oscilloscope โ Triacs are the equivalent of two SCRs connected in a _____ arrangement with gates also connected to each other. Answer: reverse-parallel
โ Triacs cannot replace SCRs in _____ applications. Answer: high- current โ An important feature of triacs is the absence of a(n) _____ condition of high voltages and high current, such as those found in diodes and SCRs. Answer: reverse breakdown โ Electrically, a diac operates in a manner similar to two _____ that are connected in series in opposite directions. Answer: zener diodes โ A diac has _____ resistance because it does not conduct current until the voltage across it reaches breakover voltage. Answer: negative โ Diacs are used almost exclusively as _____ devices. Answer: triggering โ The N-type material in a unijunction transistor functions as the _____ and has two leads. Answer: base โ As long as the emitter voltage remains less than the internal voltage, the emitter junction will remain _____, even at a very high voltage. Answer: reverse-biased
โ Photoelectric sensors that switch DC circuits normally use _____ as the switching element. Answer: transistors โ _____ current glow is the movement of electrons from positive to negative. Answer: Conventional โ Communication is the transmission of information from one point to another by means of _____ waves. Answer: electromagnetic โ A fiber optic receiver normally contains a(n) _____ that converts light back into electrical signals. Answer: photodiode โ The _____ is the first layer of protection for the glass or plastic core of an optical fiber cable. Answer: cladding โ _____ scan is a method of scanning in which the transmitter and receiver are housed in the same enclosure and the transmitted light beam is reflected back to the receiver from the reflector. Answer: Retroflective โ _____ scan distinguishes between shiny and nonshiny (matte) surfaces. Answer: Specular
โ In a(n) _____ light source, the light source is turned on and off at a very high frequency, normally several kilohertz (kHz). Answer: modulated โ The best scanning method for height and distance monitoring is _____ scan with modulated controls. Answer: direct โ The _____ light beam is the area of light that travels directly from the transmitter to the receiver. Answer: effective โ An SSR circuit consists of an input circuit, a _____ circuit, and an output circuit. Answer: control โ The input circuit is deactivated when a voltage less than the specified minimum _____ voltage of the relay is applied. Answer: dropout โ The _____ switching relay is the most widely used relay. Answer: zero โ A(n) _____ switching relay has a built-in synchronizing circuit that controls the amount of output voltage as a function of the input voltage. Answer: analog
โ A solid-state motor starter is an electronically operated switch (contactor) that uses solid-state components to eliminate mechanical contacts and includes _____. Answer: motor overload protection โ _____ trip is the trio point after the overloads have tripped and have been reset (motor operating near or over nameplate rated current). Answer: Hot โ A typical solid-state _____ circuit consists of both start and run contractors connected in the circuit. Answer: starting โ _____ start is the most common solid-state starting method. Answer: Soft โ _____ stop is the most common solid-state motor starter stopping method. Answer: Soft โ The _____ starting method provides the highest possible starting torque per ampere of line current and is the most effective means of motor starting for applications where the inrush current must be reduced with a minimum sacrifice or starting torque. Answer: autotransformer
โ _____ drives are the most common drives because they can easily vary the speed of a 3 phase motor. Answer: AC โ The control circuit for a motor drive does not require a _____ because the motor drive provides the control circuit power at the terminals where the control devices are connected. Answer: control transformer โ A(n) _____ (with resistance of 5 kOhms to 10 kOhms) can be connected directly to the motor drive control terminals as specified by the manufacturer. Answer: potentiometer โ Basic motor drives can contain approximately _____ parameters. Answer: 30 โ _____ parameters are normally the most conservative and frequently used parameter values that create the least amount of risk to equipment and personnel. Answer: Default โ _____ parameters are parameters that can be programmed or adjusted to set a drive for a specific application and motor. Answer: Editing
โ A(n) _____ filters the voltage and maintains the proper DC voltage level in a motor drive. Answer: DC bus โ _____ in electric motor drives are 1 phase full-wave rectifiers, 1 phase bridge rectifiers, or 3 phase full-wave rectifiers. Answer: Converters โ _____ to an AC motor drive is limited by the size of the conductors to the drive, fuse and circuit breaker sizes, and the transformer(s) delivering power to the system. Answer: Current โ Normally, a surge suppressor consists of _____ varistors, connected to the converter of a motor drive. Answer: metal-oxide โ _____ in a DC bud are changed from rectified DC voltage produced by the converter. Answer: Capacitors โ _____ in an AC motor drive are the most important part of the drive because they determine the voltage level, voltage frequency, and amount of current that a motor receives. Answer: Inverters โ A motor heats excessively and damage occurs to the windings if the voltage is not reduced when _____ is reduced. Answer: frequency
โ _____ frequency is the frequency that controls the number of times solid-state switches in the inverted of a motor drive with pulse width modulation turn on and off. Answer: Carrier โ Derating a motor drive decreases the _____ rating of the drive. Answer: power โ Pulse width modulation controls the amount of _____ output. Answer: voltage โ _____ stop is a stopping method in which the programmed deceleration time is doubled and the stop function is changed from a ramp slope to an S-curve slope. Answer: Soft โ An electronic overload is a device that has built-in circuitry to sense changes in current and _____. Answer: temperature โ The first programmable controllers were developed to eliminate individual control relays and _____ by consolidating them into one unit that could be programmed and reprogrammed as required by the application. Answer: timers โ The main advantage of programmable _____ is that they combine the latest technologies, programming methods, and communication
โ Examples of _____ inputs are potentiometers, rheostats, encoders, bar code readers, and temperature, level, pressure, humidity, and wind speed transducers. Answer: data โ The leakage current problem caused by using a two-wire thyristor output can be corrected by placing a load _____ across the input device. Answer: resistor โ Electrical _____ is unwanted signals that are present on a power line. Answer: noise โ A(n) _____ circuit is used to suppress a voltage spike. Answer: snubber โ The _____ section is the brain of a programmable controller and can be referred to as the central processing unit (CPU). Answer: processor โ _____ time is the time it takes a programmable controller to make a sweep of the program. Answer: Scan โ In the _____ mode of a programmable controller, a circuit is monitored and the program is edited, changed, saved, and transferred. Answer: program
โ _____ programming is the use of a PC to program a programmable controller that is not in the run mode. Answer: Off-line โ The first programmable controllers used _____ diagrams as a language to input information. Answer: line โ A typical controller scan starts in the _____ corner of the line diagram. Answer: upper-left โ A _____ diagram is a line diagram that better matches the language of the programmable controller. Answer: programming โ A programmable controller's _____ lamp should normally be energized. Answer: power โ Extreme caution must be used any time a programmable controller's _____ lamp is energized. Answer: forced I/O โ Care must be taken when using the _____ command because it overrides all safety features designed for the program. Answer: force โ A(n) _____ operation is an operation that has feedback from the output to the input. Answer: closed loop
โ When an output device does not operate, the problem may lie in the output module, output device, or _____. Answer: controller โ The input status indicator located on the input module should turn off and the input symbol should no longer be highlighted in the control circuit on the monitor screen when an anachronism input device is ______. Answer: open โ
