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A diode is reversed biased when the ____________ is connected to the negative side of the external voltage source and the _______________ is connected to the positive side..
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A semiconductor material with an excess of free electrons is called a(n) ______________ material.
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motor controls 2
motor controls 2 test review
| ___ | Answer |
|---|---|
| A diode is reversed biased when the ____________ is connected to the negative side of the external voltage source and the _______________ is connected to the positive side.. | anode / cathode |
| A semiconductor material with an excess of free electrons is called a(n) ______________ material. | N-type |
| lesson 9 start | |
| the __________ region of a PN Junction widens beyond the no bias width, and current flow drops to _____ . | depletion region/ zero |
| The reverse bias circuit makes the _________ or cathode end more positive than the __________ or anode end. | N/P |
| The small current that does flow in a reverse bias mode is called the _________________ current. | leakage |
| _________________ and ____________ diodes are used more than any other type. T/F | small signal/power |
| The __________ is a semiconductor device that allows current flow in only one direction | Diode |
| When forward bias voltage is applied , diode resistance is ______________________, until the applied voltage exceeds the ____________________ .(0.6 for silicon) | High/barrier voltage |
| After the barrier voltage is exceeded the diode resistance drops to a ________________ value. | Low |
| In reverse bias the diode resistance is VERY high with only ______________ current flowing until the ___________________ point is reached. | leakage current/ breakdown point (700v DC) |
| At the Breakdown (point)the reverse voltage is high enough to pull electrons from the atoms shells in the _______________________ | P material |
| The diodes ability to limit current flow to a single direction, makes it an ideal rectifier to convert AC voltage to ______________ ___________________voltage. | pulsating DC |
| _____________________ is the most common application for silicon power diodes. | Rectificaion |
| What are the three terminals of the JFET (junction FET)? | drain, source, gate |
| What are the three terminals of the NPN/PNP transistor? | collector, source, base |
| The current flow between the source and the drain is controlled by the _______________ on the gate. | voltage |
| The ___________ was developed to control AC current flow to a load for both halves of the AC cycle | Triac |
| The terminals of the Triac are the gate, main Terminal 1 (MT1) and _____________________, current flows in either direction between MT1 and MT2. | main terminal 2 (MT2) |
| Unlike the SCR the Triac controls current flow during both halves of the AC cycle. | |
| The ___________ is controlled by current. | BJT |
| The ______________________ is controlled by voltage. | FET |
| A ? has three leads, identified as drain, source, and gate. | JFET |
| A(n) __________________ has three leads, identified as anode, cathode, and gate. | SCR |
| In a Triac ________________________ is initiated by a commentary trigger pulse. | conduction |
| Unlike the SCR the Triac controls __________________flow during both halves of the AC cycle. | current |
| In the non-conduction state, the Triac blocks current flow between MT1 and MT2. Conduction is initiated by a ______________________ pulse applied to the gate . | momentary trigger |
| Unlike the SCR the _________________________ controls the current flow in during both halves of the AC cycle. | Triac |
| Triacs have lower maximum current levels compared to SCRs with maximum currents in the _________________ ampere range | 50 |
| start chapter 10 | |
| Discrete mechanical sensors have contacts that open and close. Since discrete electronic sensors often do not have mechanical contacts, the output condition is described as activated or de-activated. T/F | True |
| Capacitive, inductive and ultrasonic are three types of ____________________________ sensors that are based on the sensor’s operating principles. | proximity |
| Sensors that use an NPN transistor to switch DC loads are current __________________ devices. | Sinking |
| Solid state input devices have no moving parts and do not rely on ______________________ contact with any other object or process parameter. | direct |
| Discrete mechanical sensors have contacts that open and close. Since discrete electronic sensors often do not have mechanical contacts, the output condition is described as activated or de-activated. | True |
| The BJT is used most often to link solid state sensors to their _____________________. | loads |
| The BJT has two configurations __________________________ and ____________________________. | current sinking/ current sourcing. |
| Sensors that use an NPN transistor to switch DC loads are current- ____________________________ devices. (BJT) | sinking |
| Current-sinking outputs use the _______ side of the DC output circuit as the switch leg to the load device | negative |
| Sensors that use a PNP transistor to switch DC loads are current_____________________ devices. | sourcing |
| Current-sourcing outputs use the ______________________ side of the DC output circuit as the switch leg to the load device. | positive |
| ________________________ devices are non-contact solid-state devices that use light to detect the presence of objects. | Photoelectric |
| Response time, sensitivity, operation margin, and light/dark operation are four parameters that are commonly used to describe the operation of ? devices | photoelectric |
| Discrete mechanical sensors have contacts that open and close. Since discrete electronic sensors often do not have mechanical contacts, the output condition is described as activated or de-activated. | TRUE |
| Capacitive, inductive and ultrasonic are three types of ______________ sensors that are based on the sensor’s operating principles. | proximity |
| Light operate and Dark operate are used to set the ________________ of a sensor output when a target is present | condition |
| Response time, sensitivity, operation margin, and light/dark operation are four parameters that are commonly used to describe the operation of ? devices. | photoelectric |
| The ____________________________ modes enable a photoelectric sensor to detect whether a target is present or absent. | light/dark operation |
| Proximity sensors that detect objects using an electrostatic field are known as ________ devices. | capacitive |
| Proximity sensors that detect objects using an electromagnetic field are known a ____________________________devices. | Inductive |
| _____________________ devices are solid-state sensors that detect the presence of a magnetic field. | Hall effect |
| The input section of the SSR performs the same function as a _________________________ relay | electromechanical |
| A ________ solid-state relay is an electronic device with control functions that include relays, timers, and counters. | programmable |
| SSRs are available with a variety of AC or DC input voltages, AC or DC output voltages, and output circuit ampacities from ________amperes to ________ amperes. | 30 to 40 |
| The input and output sections of an SSR are electrically isolated, by the use of a(n)_____________________. | optical coupling |
| The input section of an SSR performs the same function as the _______________ of an electromechanical relay. | coil |
| The output section of an SSR performs the same function as the _______________ of an electromechanical relay. | contact |
| ________________________ is the most common technique used to link SSR inputs to outputs. | optical coupling ( or opto-isolation) |
| Some SSR's have a fixed input voltage of 12v DC, but most SSRs accept AC voltage ranges such as ___v DC to ___v DC.....However some SSRs accept AC voltage inputs up to __________v AC. | 3 to 32 up to 277 |
| The SSR is configured to operate as _________________ independent circuits. | 2 |
| semiconductor fuses are a reliable way to protect solid state relays and are also referred to as ______________________ fuses and provide extremely fast operating (about 2 msec) while restricting pass though current far below the current level that could destroy the SSR | current- limiting |
| Semiconductor fuses fully protect SSRs against rapid rise, ________________________ currents. | overload |
| Every SSR has a ____________________ rating which is used to identify a matching fuse rating for protection. | I^2T |
| Trouble shooting PLRs. In General devices attached to the PLR are the cause for improper operation more often than a failed PLR. T/F | T |
| __________________ the load is a condition that occurs when the input control device is faul | Failure to energize |
| chapter 12 lesson 5 | |
| MCC Size _____________ or smaller units or buckets, are factory-wired from unit-located terminal blocks to the master terminal blocks. | 3 |
| In corrosive atmospheres, copper buses in MCCs are often coated with _______________________ to protect the bus from corrosion. | Tin |
| The fault current withstand rating of the MCC is determined by the _______________ rated device within the MCC. | lowest |
| The ____________________ distributes power to the control units via a horizontal and vertical bus. | internal power bus |
| Bus material is usually copper, however some installations use __________________ to reduce costs. | aluminum |
| When performing maintenance on an MCC, what does the presence of ozone odor indicate? | Arcing |
| When performing maintenance on an MCC, what does discoloration of bolted electrical connections and insulation indicate? | Overheating |
| Reduced motor starters (ARE/ ARE NOT) typically used for single phase AC motors because they are smaller, typically less than 5 horsepower, and are started directly from the line voltage. | Are Not |
| At a minimum, how often are MCCs checked to avoid unnecessary downtime ? | semi-annually |
| chapter 12 lesson 6 | |
| Smaller 3-phase motors are normally controlled using ____________________ voltage across the line starters. | Full |
| The internal power bus distributes power to the control units via a horizontal and a __________________ bus. | vertical |
| Reduced voltage starting _______ inrush currents and _________ the impact on the distribution systems. | lowers / lessens |
| The high inrush currents for large horsepower AC motors can cause _____________________ in the power distribution system. | interference |
| The coils of a dual voltage motor are connected in _________________ for higher voltage and in ___________________ for lower voltage. | series /parallel |
| In ______________________ - reduced voltage starting, a silicon-controlled rectifier (SCR) controls the voltage and current to the motor during acceleration. | Solid-state |
| A(n) _____________is composed of a cathode, anode, and gate. | SCR |
| When a signal is applied to the___________________, it acts as a “trigger” that turns the SCR on and off. | gate |
| By triggering the SCR on and off at specific intervals during each cycle of the sine wave, this starting method controls the voltage and current delivered to the motor windings while the motor is accelerating. | Solid-state reduced voltage starting |
| The____________ the gate has a signal, the _________ the SCR remains on, and the greater the voltage and current is supplied to the motor. | longer/longer |
| ___________________ provide the smoothest acceleration and greatest control of current and torque for squirrel cage motors than any other starting technique. | Solid-state reduced voltage starters |
| A _______________ programmed timing function retains its accumulated value between input signals. | retentive |
| Retentive timers are programmed with a preset _________ and a time ________. | time/base |
| Non-retentive timers are programmed in a specific mode such as, on-delay, off delay, one shot, or recycle with a preset value and a time base. T/F | True |
| The ____________ value is used to set the amount of time that a timer counts BEFORE completing an operation. ( before timed contacts change states.) | preset |
| ____________________ is used to set the precision of a timer. | Time base |
| ________________________ clock timers energize and de-energize output contacts at preset times of the day and days of the week. | Real Time |
| The ______________ value is the current number of time units a programmed timer has counted after the timing period has been initiated | accumulated |
| Programmable logic relay timing functions provide an adjustable _____________________ that allows precise timing with accuracy within a hundredth of a second. | Time base |
| Programmed timers’ output contacts change state when the ___________________ value equals the preset value. | accumulated |
| Typical time bases available for programmable timers are 0.01, 0.1, and 1.0 seconds . T/F | True (Not MINUTES, watch for that on the test) |
| The actual amount of time a programmable timer measures is the ___________________ value (X) the time base | preset |
| Programmable ____________________ timers can emulate a seven-day time clock. | real time clock |
| Programmed timers’ output contacts change state when the _________________ value equals the preset value. | accumulated |
| Many latching relays contain contacts that prevent continuous power being applied to the coil after it has been energized. These contacts are usually called Coil _________________ contacts. | Clearing |
| Latching relays have contacts that prevent continuous power from being applied to the coil after it has been energized | coil clearing contacts |
| _______________ latching relays use residual magnetic force to hold the contacts in position after the coil is de-energized. | Magnetic |
| phase sequence relays have a variety of applications such as monitoring compressor lines communication bases and _______. | Pumps |
| _________ are electronic devices that monitor a 3-phase input for phase failures such as out of phase sequence,a lost phase or a too high or too low input voltage level | Phase sequence relays |
| _____________are electronic devices that monitor AC and/or DC voltage levels and provide an output when the output is out of specification. | Voltage sensors |
| The two most commonly used voltage sensors are______________ relay and __________ relay. | Over voltage/undervoltage and voltage band |
| Chapter 9 | |
| To operate a wound rotor motor at full speed, the rotor windings must be ___________. | Shorted together |
| Single-phase motor speed control circuits use SCR or ______ to control power to the motor for speed control | Triacs |
| In a single-phase motor speed control, the thyristor controls power in the circuit by changing the ___________ angle of the AC sine wave that drives the motor. | Firing |
Created by:
Shawnt321