Lab Manual Solutions Industrial Control Electronics: Devices, Systems, and Applications

Transcription

1 Lab Manual Solutions Industrial Control Electronics: Devices, Systems, and Applications 3rd edition Terry L.M. Bartelt Australia Canada Mexico Singapore Spain United Kingdom United States

2 . analog 2. linear 3. greater 4. 6, 5. -5V Experiment Operational Amplifiers INPUTS V V 2 (V) V OUT Figure -2 b -5V +5V -5V V +5V -5V V IN V OUT V IN V OUT +.2V -V +.3V -.75V.4V +2V.5V +.38V V V 2.V +5V +.32V -.6V +.4V -V Figure -3 b&c Input Voltage Output Voltage V V2 V3 Measured Calculated +V +V +V -3V -3V +V V V +V +V +2V V V V V 3V V +3V +V +V +V +2V V -2V -2V Figure -4b

3 Experiment 2 Schmitt Trigger Procedure Question Answer. No. Because the 7476 J-K flip-flop is negative edge triggered, and reacts only to positive-to-negative going signals that change abruptly. The rectified sine wave does not change fast enough. Step 5 Step 7 Point V th = VDC.9 V + = VDC.7 th Table 2- Waveform At Point At Point 2 Is the Flip-Flop Toggling (Yes, No) Circuit (a) NO Circuit (b) YES Table Convert electronic signals to square waves. - Perform NAND gate and Inverter logic functions. 2. D. 3. edge 4. Low, High 5. hysteresis 6. Because when sine waves are counted, they must be converted to square waves before being applied to a flip-flop. 2

4 Experiment 3 Magnitude Comparator Procedure Question Answer. If the high order bits are equal, then the output state is determined by comparing the low order bits. Step 2A Step 3B Input B Input A Outputs B 3 B 2 B B A 3 A 2 A A A<B A=B A>B Table 3-2 Input B Input A Expansion Inputs Outputs B 3 B 2 B B A 3 A 2 A A I A<B I A=B I A>B A<B A=B A>B Table Yes. By connecting a Low to the MSB of inputs A and B, and applying the three binary bits to the remaining inputs. 3. I A > B = I A = B = I A < B = When A is greater than B, or B is greater than A, the circuit would operate normally. When A is equal to B, however, output A<B would incorrectly go High instead of output A=B. 3

5 Experiment 4 SCR Phase Control Circuit Step 3 69 volts, yes Step 4 5 volts, yes. D. 2. B = A. 5. B. 6. B. No Power to Load Half Power to Load Full Power to Load Input TP TP 2 TP 3 TP 4 TP 5 Across Lightbulb Figure 4-4

6 Experiment 5 Photoresistor Step Dark Resistance = 4KΩ Step 3 Ambient light voltage = 8V Dark Voltage = +7V Design Question Switch the position of R with that of the photoresistor.. A. 2. B. 3. B. 4. B. 5. A. 5

7 Experiment 6 Optocoupler Step Meg ohm Step 2 5 ohms Step 4 LED On/Off Condition O v Optoisolator (Transistor) Output O v Step 5 B Step 6 25KHz Step 7 I C = 3.5mA I f = 6mA CTR 22%. True 2. A. 3. A % 5. C. 6

8 Experiment 7 Digital-to-Analog Converter Procedure Question Answers. A. 2. A (2 4 ) Eight different voltage levels. When an open is at the LSB input, a binary is always applied to the LSB digital input lead of the D/A converter. This causes the D/A converter to produce the following counts: Desired Count Count with Pin 2 Open

9 8 Experiment 7 Digital-to-Analog Converter The number of outputs is determined by multiplying 2 by the power of the number of inputs applied to the digital input of the D/A converter (2 5 ) Change V REF applied to pin 4. - Change the resistor value connected to pin 4. - Change the R F resistor connected to pin 4.

10 Experiment 8 Analog-to-Digital Converter Procedure Question Answer. They should be equal. Step 4 Input Measured Analog Voltage V.4V.V.6V 2.3V 3.5V 4.6V 5.2V A/D Converter Test Results Output Resolution Values DB7 DB6 DB5 DB4 DB3 DB2 DB DB 2.56V.28V.64V.32V.6V.8V.4V.2V Table 8- Resolution Total V.4V.V.6V 2.3V 3.5V 4.6V 5.2V Low 4. 9

11 Experiment Clock Timer (Astable Multivibrator) Step R A (Ω) R B (Ω) C (µf) 47k k 22k k 22k k. 22k 2.2k. k k..44 f = (R A + 2R B ) C calculated (Hz) F out (Frequency Out) Measured (Hz) Chart Values (Hz) Table 9-. astable 2. Values of external components 3. Nothing. Just apply power and it runs by itself. 4. They provide pulses that are necessary to time and control the proper sequencing of all events throughout a computing system Hz 6. 9K ohms

12 Experiment 555 Clock Pulse (Monostable One-Shot Multivibrator) Step 3 R A (Ω) C (µf) T =. R AC calculated T measured Chart Value M sec sec sec 47k 5.7 sec 5.3 sec 5 sec k sec 5.7 sec 5 sec k. sec.5 sec.5 sec 47k sec 27.3 sec 25 sec. Low, High 2. It automatically does it by itself By a mechanical push button - By another circuit 4. - Enter numbers into digital circuits - Empty numbers out of digital circuits - Producing time delay signals - Pulse stretchers - Bounceless switches - Reshaping ragged pulses 5. T =. x K x ufd = milliseconds 6. 9 ohms Table -

13 Experiment Integrator Operational Amplifier Step 4 Input VDC 2 VDC 3 VDC Output after 5 seconds 5.7V 9.4V 9.5V Output after seconds 7.V.9V 2.4V Output after 5 seconds 8V 2.5V 2.6V Output after 2 seconds 8.9V 2.6V 2.6V Note: Voltages are all negative Table -. yes 2. A. 3. faster 4. saturation 5. directly, directly 2

14 Experiment 2 Differentiator Operational Amplifier Step 8 PPK Square Wave Outputs Input is a.4vpp Saw Tooth 3Hz 75Hz khz.25khz.5khz.75khz 2kHz 5V P-P 2V P-P 6V P-P 2V P-P 25V P-P 27V P-P 27V P-P Table 2-. directly 2. A. 3. C. 4. C K 3

15 Pressure Readings with a Manometer Step 3B Primary Level = Secondary Level = Step 6B Primary Level = 4 Secondary Level = +4 Step 7B Total Change = 8 inches Step 8B 8 inches changed x.49 = (PSIG) = 8.7 psia Step 5C 8.8 difference in inches Step 6C 8.8 x.49 = 4.3 psid. B. 2. B. 3. B = psig = 8 psia 6. Zero Experiment 3 4

16 Solid State Pressure Transducer Step 4A.7 Step 7A Step 7B PSI V OUT Experiment 4 High Pressure Low Pressure Differential Pressure V OUT A. 2 2 B C D E F G D. 2. A., B. 3. A., C. 4. A., B. 5. A. 6. B. 7. A., A. 5

17 Step 3A Step 3B Step 2C Conversion of Standard Signals Calculated Current Measured Current 6 psi 8mA 8mA 9 psi 2mA 2mA 2 psi 6mA 6mA Calculated Pressure Measured Pressure 8mA 6 psi 6 psi 2mA 9 psi 9 psi 6mA 2 psi 2 psi Applied Pressure P/I Output Current I/P Output Pressure 3 psi 4mA 3 psi 6 psi 8mA 6 psi 9 psi 2mA 9 psi 2 psi 6mA 2 psi 5 psi 2mA 5 psi. C. 2. D. 3. C., B. 4. E., D. 5. B. 6. B. Experiment 5 6

18 Experiment 6 Resistance Temperature Detector (RTD) Step 3 RTD Hot Cold Actual Temperature (Thermometer Reading) Ohmmeter Reading Temperature from the Manufacturer s Table C 36.6Ω C C.2Ω C Temperature Settling Time Min 5 Sec. B. 2. A Table 6-7

19 RTD Transmitter Calibration Step A Cold Bath Measurement.4 C Step A Hot Bath Measurement 99.8 C Step 2B % of SPAN C C 5 75 C C Transmitter Input Values Temperature Applied CALIBRATION CHART Ideal Current Transmitter Output Values As Read After Calibration As Found Before Calibration Experiment 7 Amount of Error % Error 4mA mA mA mA C 2mA Step 4C Cold Bath Temperature C Transmitter Output Current 4.8mA Step 5C Hot Bath Temperature C Transmitter Output Current 4mA. A. 2. A. 3. C., E. 4. C. 5. True 8

20 Experiment 8 Step 9,6 ohms B. B. Step 7 Before Inverting Input = Ideally 4.2 volts Non-inverting Input = Ideally 4. volts Output = Ideally 2 volts Thermistor Step 8 No No After Inverting Input = Ideally 4. volts Non-inverting Input = Ideally 4. volts Output = Ideally +2 volts. B. 2. C., B. 3. B., A. 4. holding 5. B. 9

21 Experiment 9 Step 4A Thermocouple Sensor Thermocouple Hot Cold Actual Temperature (Thermometer Reading) mv Reading (Voltmeter Reading) Temperature from the Manufacturer Table C.4mV 8 C.2 C.mV C Temperature Settling Time 3 Seconds Step 8A Question No Step 2B Table 9- Thermocouple Hot Cold Actual Temperature Thermocouple mv Reading (Voltmeter Reading) C 5.mV.2 C mv Temperature from the Manufacturer Table C Temperature Settling Time 25 Seconds Step 7B Question Yes Step 2C Step 7C Questions same, longer Table 9-3 Thermocouple Hot Cold Actual Temperature Thermocouple mv Reading (Voltmeter Reading) C 5.2mV C Temperature from the Manufacturer Table 99 C Temperature Settling Time 2 Min 5 Sec Table 9-4 2

22 Experiment 9 Thermocouple Sensor 2. subtract from 2. more 3. longer mV; no, but close enough

23 Step 9A Cold Bath Measurement. C Step A Hot Bath Measurement C Experiment 2 Thermocouple Transmitter Calibration Step 2B % of Span (Transmitter Input Values) Temperature Applied Ideal Current C 4mA C 8mA 5 75 C 2mA 75 2 C 6mA 5 C 2mA Transmitter Output Values As Found As Read Before Calibration After Calibration ma ma 7.24mA 8mA.mA 2mA 5.2mA 6mA 8.8mA 2mA Table 2- Step 4c Cold Bath Measurement C Transmitter Output Current 4.9mA Step 5c Hot Bath Temperature C Transmitter Output Current 4.7mA. A., E. 2. C. 3. C. 4. D. 5. True 22

24 Experiment 2 Step 2B Differential Pressure Flow Measurements Pressures (inches of H 2O) L-Port H-Port Calibrator Output (ma) Differential Pressure (Inches H 2O) Flow rate (GPM) Pressure Conversion (PSI) A., B. 2. Zero 3. Heating, ventilating, air conditioning 4. C. 5. A., B., A. 6. C., E. Table 2-23

25 Experiment 22 Purge Level Measurement Method Step 2B Water Level in Inches 25 5 Display Module Reading 25 5 P/I Converter Output 4 ma 2 ma 2 ma Static Pressure Head psi.9 psi.8 psi Calculated Water Level inches 25 inches 5 inches Table 22-. A. 2. 4mA, psi, inches 3. 2mA,.8psi, 5 inches 4..7 psi x 27.7 = 9.4 inches inches x.36 = 2.8 psi 24

26 Experiment 23 Differential Pressure Level Measurements Step 5 Water Level Inches/%of Span / 2.5/25 25/5 37.5/75 5/ Head Pressure Ideal As Found Before Calibration As Read After Calibration % Error Error Level Measurement Table 23-. atmosphere, L 2. D. 3. B., A. 4. 3, x.36 =.9 psig psig x 27.7 = 37.5 inches 7. The pressure produced by the transmitter output is supplied from this source. 25

27 Step 2A Step 3A Step B A. Step 2B B. Step 3B C. Step 4B B. Step 5B A. ph Measurement and Control pink, acidic blue, alkaline Step 2C., B. Step 3C Reagent ph Reading Before drops. After drops 9.68 After 2 drops 6.27 After 3 drops 3.3 After 4 drops 2.65 After 5 drops 2.57 The solution becomes neutralized as an acid solution is added. Step 6C 3.32, A. Step 7C Reagent ph Reading Before drops 3.32 After drops 3.34 After 2 drops 3.6 After 3 drops 3.68 After 4 drops 3.86 After 5 drops 3.96 The solution becomes neutralized as an alkaline solution is added. Experiment 24 26

28 Experiment 24 ph Measurement and Control 27 Step 2D 4.6 Step 3D Reagent ph Reading Before drops 4.59 After drops 4.6 After 2 drops 4.62 After 3 drops 4.64 After 4 drops 4.66 After 5 drops B C. 4. A. 5. C. 6. B.

29 Experiment 25 Conductivity Measurements Step A Water Supply Sources Lab Tap Water Distilled Water Hard Water Softened Water Table 25- Step 2A Most Impurities: Softened Fewest Impurities: Distilled Container Brine Solution A Brine Solution B Brine Solution C Conductivity.4mS.2mS.6mS 4.3mS ph Readings Table 25-2 Container Brine Solution A Brine Solution B Brine Solution C Conductivity Readings Table A. 2. B. 3. B. 4. C. 5. False 28

30 Step 3A Step 4A Step 2B Step 3B Step 4B Step 5B Step 6B Reading One 57 Humidity Measurements Wet Bulb Reading Reading Two 56 7 Reading Three 55 Relative Humidity 38% Dew Point Measurements Reading One 2 Reading Two 3 Reading Three 2 Reading Four Average Temperature 2 Grams per cubic meter 8.43 Grams per cubic meter.574 RH Percentage 58.3 Experiment 26 Dry Bulb Reading. A. 2. B. 3. A. 4. B. 5. B. 6. C. 29

31 Experiment 27 Step 3A Inductive Proximity Sensor Type of Target Sensing Distance Ferrous/Non-Ferrous Plastic Brass Won't Sense 2mm No No Glass Mild Steel Won't Sense 4mm No Yes Aluminum mm No Table 27- Step 6A C Step 8A Yes Step 9A 4mm Step A 2mm, A Step 2B Hz Step 3B 2 Hz Step 4B 42 Hz. A. 2. B. 3. B. 4. A. 5. A. 6. Switching frequency 3

32 Experiment 28 Capacitive Proximity Sensor Step 3A Material Glass Plastic Water Distance (mm) 5 Step 8A 5mm Step 9A Yes Step A mm Step A A. Step C Yes Step 3C No Table 28-. B. 2. C. 3. B., A. 4. A., B. 5. B., A. 6. B. 3

33 Experiment 29 Hall Effect Sensor Step 3 Step with. D. 2. Strength of the magnet The position a magnet is placed with respect to the sensor By using a concentrator 3. 2 terminals connect to a power supply 2 terminals are the output leads 4. C. 5. A. Increases 6. A., B. 32

34 Experiment 3 Ultrasonic Sensor Step 2A, 3, 7 Part B 3 inches 4 inches 4 inches 3 inches yes Step B 4 blinks Step 2B 5 blinks Step 3B volts volts 5 volts Step 4B volts volts is Step 5B inches = volts 2 inches = 2 volts 4 inches = 4 volts 6 inches = 6 volts 8 inches = 8 volts 2 inches = volts. 5 minutes 2. 2 blinks 3. 3 inches volts 33

35 Opposed Sensing Optical Method Step 6A Off Step 9A Off Step A On Step 7B 2 Sheets of paper Step 8B No, 4 sheets of paper Step B ¼ inch. D. 2. True 3. C. 4. B. 5. C. 6. True Experiment 3 34

36 Experiment 32 Retro-reflective Optical Sensing Step 7A Step 8A 35 Step 3B No Step 4B largest Step 6B 5, 7, Plastic reflector Step 2C Yes Step 3C No Step 4C Yes Step 5C Yes Step 6C No Step 7C No Step 8C Yes Step 9C Yes 35

37 36 Experiment 32 Retro-reflective Optical Sensing Step 3C No Step 4C Blocked, Blocked B. 3. A. 4. A. 5. C. 6. A., C., D. 7. A.

38 Step 7A Gray 6 Black 5 Red 7 White 8 Step 9A 3 Step A Black 2 Red 4 White 5 Step 2A Gray 3 Black Red 4 White 5 Step 3A Step 4A 4 Step5A 2 8 Yes Step 2B 8 Step 3B 5 Step 4C no Step 3D Yes Step 4D No Step 7E 3mm Step 9E 8mm decrease Diffuse Optical Sensing Method. A. 5. A., B. 2. B. 6. B. 3. B. 7. C B. 37 Experiment 33

39 Step 6A.5 seconds Step 8A 3 seconds Step A 2 seconds Step 3 A 22 seconds Step 3B A. Step 4B B. Step 2C No, seconds Step 3C 2 seconds Step 5C 2 second, No. A. 2. B. 3. C. 4. DNM L DNM Fully CW 5. C. Experiment 34 Timing Functions of Sensors 38

40 Step A No, Off Step 2A.44mA Step 3A Yes, On Step 4A.4mA Step B Off Step 2B No Step 3B On, Yes, 8.5 Step 4B into, sinking Step 5B No Step 6B No Step 7B On, Yes, 5.7mA Step 8B out of, sourcing Step 2C.4 volts. No Step 3C volts,.3 volts Step 4C No Step 5C Yes Step 6C 2.94 volts, 2.6 volts, 4 sensors Step 8C Off, ma Step 9C On, 6.72mA Step C 79mA, A. Brown D. Blue A. White B. Black C. 2. A. 3. B. 4. B B. Experiment 35 Sensor Output Wiring 39

41 Experiment 36 Ladder Logic Design Exercise ANSWERS

42 Experiment 36 Ladder Logic Design Exercise

43 42 Experiment 36 Ladder Logic Design Exercise 7. 8.

44 Experiment 36 Ladder Logic Design Exercise

45 Experiment 37 Programmable Controller Design Exercise. LADDER DIAGRAM DUMP START 5 4 ]/[ ] [ ( ) 4 ] [ 2 5 ] [ ( ) END 37 - N.O. Start PB 2 - N.O. Stop ( ) 4 - Output Coil and Solenoid ] [ 4 - Latching Contact ( ) 5 - Output Coil ]/[ 5 - NC Stop Contact 44

46 Experiment 37 Programmable Controller Design Exercise LADDER DIAGRAM DUMP START 2 2 ] [ ] [ ( ) 2 ] [ END 35 - Maintained input represented by a toggle switch 2 - N.O. PB representing a momentary input ( ) 2 - Output Coil representing output ] [ 2 - Latching Contact 3. LADDER DIAGRAM DUMP START ] [ ] [ ] [ ( ) 6 ] [ ] [ END LSI 3 - PSI 4 - TI - PBI 6 - T2 - Indicator Lamp representing output

47 46 Experiment 37 Programmable Controller Design Exercise 4. LADDER DIAGRAM DUMP START 2 2 ]/[ ] [ ( ) 2 ] [ 2 ] [ ( ) ] [ ]/[ ( ) 4 ] [ ( ) END NC Stop PB (Wired N.O. Switch) - Start PB ( ) 2 - Internal Output Coil ] [ 2 - Latching Contact ( ) 2 - Internal Output Coil ( ) 4 - Output Coil and Relay to represent output ] [ 4 - Contact energized by Output Coil ( ) - Output Light (used in addition to Relay to represent output) 5. LADDER DIAGRAM DUMP START 7 35 ]/[ (TON). PR AC ]/[ ] [ ( ) END Toggle Switch representing maintained input 35 - Timer On (Output turns to a " " state sec. after an input is supplied) 355]/[ - N.C. Contact controlled by output of timer - Indicator Light representing output

48 Experiment 37 Programmable Controller Design Exercise LADDER DIAGRAM DUMP START 2 2 ] [ ( ) 2 35 ] [ (TOF). PR AC ]/[ ] [ ( ) END On/Off Toggle input switch ( ) 2 - Internal Output ] [ 2 - Contact 35 (TOF) - Timer Off (Output goes to a " " state as soon as a " " state input is applied. The output will remain "HIGH" for seconds after input is removed) - Indicator Lamp representing output

49 48 Experiment 37 Programmable Controller Design Exercise 7. LADDER DIAGRAM DUMP START 2 2 ] [ ]/[ ( ) 2 ] [ 2 35 ] [ (TON). PR AC ]/[ ] [ ( ) END 4 - Momentary N.O. Input P.B. 2 - N.C. Stop P.B. (Wired N.O.) ( ) 2 - Internal Output Coil ] [ 2 - Latching Contact 35 - Timer On (Output turns to a " " state seconds after a "HIGH" input is applied) N.C. Contact energized from output of Timer - Indicator Lamp representing output

50 Experiment 37 Programmable Controller Design Exercise LADDER DIAGRAM DUMP START ]/[ (TON). PR AC ] [ (TON). PR 2 AC 355 ]/[ ( ) END and 36 - Timer On (Output turns to a " " state seconds after a "HIGH" input is applied) 355 and Contacts controlled by the outputs of each timer - Indicator lamp representing output

51 5 Experiment 37 Programmable Controller Design Exercise 9. LADDER DIAGRAM DUMP START ] [ ] [ ]/[ ]/[ ( ) 2 ] [ ] [ ]/[ ( ) 2 ] [ ] [ ]/[ (TOF). PR AC ] [ ]/[ ]/[ ( ) ] [ ]/[ ( ) 2 ] [ ( ) 355 ] [ ( ) END 58 - LSI 3 - Pressure Switch 2 - PBI 2 - Internal Output 2 - Internal Output 22 - Internal Output 23 - Internal Output 35 - Timer Off (Output goes to a " " state as soon as a " " state input is applied. The output will remain HIGH for seconds after the input is removed) N.O. and N.C. Contacts that are energized by the output of the timer - Indicator Lamp representing SV - Indicator Lamp representing SV2

52 Experiment 37 Programmable Controller Design Exercise 5. LADDER DIAGRAM DUMP START 2 2 ]/[ ] [ ]/[ ] [ ] [ ( ) ] [ 2 ( ) 2 2 ]/[ ] [ ]/[ ] [ ] [ ( ) ] [ END N.C. P.B. Stop Switch to stop Forward Motor (Wired N.O.) - N.C. P.B. Stop Switch to stop Reverse Motor (Wired N.O.) - N.O. Forward Start P.B. 2 - N.O. Reverse Start P.B. ( ) - Indicator Lamp representing Forward Motor ] [ - Latch Contact ( ) - Indicator Lamp representing Reverse Motor ] [ - Latch Contact 2 - Internal Output which denergizes entire circuit if low voltage occurs

53 52 Experiment 37 Programmable Controller Design Exercise. LADDER DIAGRAM DUMP START 2 ] [ ] [ ( ) ] [ ]/[ 2 2 ]/[ ( ) 2 ] [ ] [ ( ) ] [ ]/[ END 46 - N.O. Forward P.B. - N.O. Reverse P.B. 2 - N.C. Stop P.B. (Wired N.O.) ( ) - Indicator Lamp and Coil representing Forward direction ( ) - Indicator Lamp and Coil representing Reverse direction 2 - Internal Output which deenergizes entire circuit if LOW voltage occurs

54 Experiment 37 Programmable Controller Design Exercise LADDER DIAGRAM DUMP START 2 ]/[ ] [ ( ) 2 ] [ 2 ] [ ] [ ( ) 2 2 ] [ ]/[ ] [ ] [ ( ) 22 ] [ ]/[ 2 2 ] [ ]/[ ( ) 2 ] [ 2 22 ] [ ]/[ ( ) 22 ] [ END 65 - N.C. System Power Stop P.B. (Wired N.O.) - N.O. System Power Start P.B. 2 - Internal Output representing main power for planer table - LSI to indicate end of travel to right 2 - LS2 to indicate end of travel to left - Indicator Lamp that represents right directional travel 2 - Indicator Lamp that represents left directional travel The two bottom rungs ensure that the table will resume the same direction of travel when power is restored after power has been interrupted

55 Incremental Encoder Step 3 64, 36 /256 counts =.4 per count Step 4 Yes Step 5 No The number of pulses produced during one revolution does not equal the maximum count in the counters. Step 6 No The number of pulses produced during one revolution does not equal the maximum count in the counters. Step 7 No Step 8 28, Yes. B. 2. A. 3. B. 4. B. 5. B. Experiment 38 54

56 Experiment 39 Step 4 Absolute Encoder Column A Gray Code L L4 Column B Binary Code (F F4) L L2 L3 L4 F F2 F3 F4 Column C Dial Range (In Degrees) to 22½ 23 to 45½ 46 to 68½ 69 to 89½ 9 to ½ 2 to 32½ 33 to 54½ 55 to 8½ 82 to 22½ 23 to 225½ 226 to 245½ 246 to 269½ 27 to 292½ 293 to 34½ 35 to ½ to 36 Table 39-. True 2. A = 36/64 = B. 5. B. 55

57 Experiment 4 Step 2B 992RPM DC Variable Speed Drives Table 4- Step 4C C. Armature current stays constant B. Motor speed decreases Step 3D B. Step 4D The motor takes a long time to speed up or to slow down.. B. 2. B., A. 3. A. 4. A. 5. C. 6. C. 7. C. Generator Load Motor.A.2A.4A.6A.8A.A Motor Speed Before IR Comp Adjustment RPM Motor Speed After IR Comp Adjustment 4 RPM

58 Experiment 4 Motor Breaking Procedure Questions 6A 3 7A +3, opposite. A. 2. True 3. B. 4. B. 57

59 Potentiometer Setting Time Proportioning DC Circuit Approximate Duty Cycle Table 42- Calculated Average DC Voltage (Pk On-Time Volts DutyCycle Experiment 42 Measure Average DC Voltage V V V 2.5V V 2.5V 5.V 5 5.V 5.V 7.5V V 7.5V.V V V. B. 2. B., A. 3. C. 4. A. 58

60 Experiment 43 Time Proportioning AC Circuit Potentiometer Setting Relay Input Waveform TP 2 Number of AC Cycles Across Lightbulb During Period TP 3 Lightbulb Intensity V None 2.5V 2 to 3 Low 5.V 5 Medium 7.5V 7 to 8 Brighter.V Brightest Table 43-. B. 2. C. 3. A. 4. A. 59

61 . B., A. 2. A., A. 3. A., B. 4. A. 5. C. 6. B. Experiment 44 Unijunction Transistor (UJT) Condition V E V B V B2 I B = V B VBB VB I B2 = 2 R R I E = I B I B2 Before firing < V p.9 ma After firing V V = ma 6 ma ma 2 Figure V = 2 V BB R E = 6 kω R 2 = Ω R E (kω) C f /R E C E hertz E (µf) Calculated Measured f ~ R E C E V E V B V B 2 V p-p C E =. µf R = Ω V p-p V p-p (a) (b) Figure

62 Silicon Controlled Rectifier (SCR). B. 2. B. 3. A. 4. A. 5. holding current Experiment 45 S condition S 2 condition V G V A Condition of SCR (on or off) A A off B A.7.8 on A A.7.8 on A B off A A ff (b) Figure 45-6

63 Experiment 46 DIAC/TRIAC (Thyristors). A. 2. B. 3. A. 4. B. 5. C. Circuit condition Before firing V T to V B Condition of Diac (on, off) Off After firing 27 On Reverse Diac in circuit Before firing to V B Off After firing 27 On (b) Figure 46- o o o o o R = kω s V V p-p at 6 Hz V Note: use only a single channel of the oscilloscope 62