1 ECET 211 Electrical Machines and Controls 2016/4/27 Class Review and Wrapping Up Comprehensive Exam, Friday, 1:00-3:00 PM, May 6, 2016 Close books/allow 1-page (8 x 11 and ½) hand-written review note, double sided Question types o Multiple choice o Fill-in blanks o Circuit diagram/drawing completion of the unfinished part o Simple calculations Ohm’s laws Simple circuit, resistance, current, etc Single phase Three-phase: Power, power factor, Line/phase voltage, line/phase current Transformer: Vp/Vs, Ip/Is, Np/Ns Three-phase Delata, Wye connections Energy, Power, Torques applications Chapter 1. Safety in the Workplace Chapter 2. Understanding Electrical Drawings Part 1. Symbols-Abbreviations-Ladder Diagrams o Motor Symbols o Motor Terms (abbreviations) o Motor Ladder Diagrams Figure 2-1 Motor Control Symbols Figure 2-3 Typical ladder diagram Figure 2-4 Motor power and control circuit wiring Figure 2-5 Identification of coils and associated contacts Figure 2-6 Load and control devices Figure 2-7 Loads and places on the right and contacts on the left Figure 2-8 Stop devices connect in series and start devices connect in parallel Figure 2-8 Differentiating between multiple devices of the same type Figure 2-10 Ladder diagram with run number detailed Figure 2-11 Numerical cross-reference system Figure 2-12 Wire numbering Figure 2-13 Alternative wiring identification with documentation Figure 2-14 Representing mechanical functions (FWD, REV) Figure 2-15 Control transformers ground connection Part 2 Wiring – Single Line – Block Diagrams o Wiring Diagrams o Single-Line Diagrams o Block Diagrams Part 3. Motor Terminal Connections o Motor Classifications
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ECET 211 Electrical Machines and Controls
2016/4/27 Class Review and Wrapping Up
Comprehensive Exam, Friday, 1:00-3:00 PM, May 6, 2016
Close books/allow 1-page (8 x 11 and ½) hand-written review note, double sided
Question types o Multiple choice o Fill-in blanks o Circuit diagram/drawing completion of the unfinished part o Simple calculations
Ohm’s laws Simple circuit, resistance, current, etc Single phase Three-phase: Power, power factor, Line/phase voltage, line/phase current Transformer:
Chapter 1. Safety in the Workplace Chapter 2. Understanding Electrical Drawings
Part 1. Symbols-Abbreviations-Ladder Diagrams o Motor Symbols o Motor Terms (abbreviations) o Motor Ladder Diagrams
Figure 2-1 Motor Control Symbols Figure 2-3 Typical ladder diagram Figure 2-4 Motor power and control circuit wiring Figure 2-5 Identification of coils and associated contacts Figure 2-6 Load and control devices Figure 2-7 Loads and places on the right and contacts on the left Figure 2-8 Stop devices connect in series and start devices connect in parallel Figure 2-8 Differentiating between multiple devices of the same type Figure 2-10 Ladder diagram with run number detailed Figure 2-11 Numerical cross-reference system Figure 2-12 Wire numbering Figure 2-13 Alternative wiring identification with documentation Figure 2-14 Representing mechanical functions (FWD, REV) Figure 2-15 Control transformers ground connection
Part 2 Wiring – Single Line – Block Diagrams o Wiring Diagrams o Single-Line Diagrams o Block Diagrams
Part 3. Motor Terminal Connections o Motor Classifications
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o DC Motor Connections Dynamic braking
o AC Motor Connections Dual voltage motor connections Multispeed motor connections Motor direction change
Part 4. Motor Nameplates and Terminology o NEC Required Nameplate Information
Motor Manufacturer, Voltage Rating, Current Rating Line Frequency, Phase Rating, Motor Speed Ambient Temperature, Temperature Rise, Insulation Class Duty Cycle, Horsepower rating Code Letter, Design Letter
o Optional Nameplate Information Service Factor, Motor Enclosure, Frame Size, Efficiency, Power Factor Thermal protection, Connection diagrams
o Guide to Motor Terminology, p. 38 Across-the-line, lock-rotor current, ..
Part 5. Manual and Magnetic Starters
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Chapter 3. Motors, Transformers and Distribution Systems Part 1. Power Distribution
o Transmission Systems o Substations
Unit Substations
High-voltage primary switchgear
Transformer sections
Low-voltage distribution section o Distribution System
Figure 3-6 Typical commercial/industrial distribution system Figure 3-7 Single-line diagram for a typical distribution system
Speed measurement Ultrasonic Sensors Temperature Sensors
Thermocouple
Resistive Temperature Detectors (RTDs)
Thermistors (Negative temperature coefficient)
IC package
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Velocity and Position Sensors
Tachometer
Magnetic pickup
Encoder Flow Measurement
Turbine flow meters
Target flow meters Magnetic Flowmeters
o Part 4. Actuators Relays
Figure 4-63 Electromechanical relay
Figure 4-64 Relay motor control circuit Solenoids
Figure 4-67 Solenoid construction and operation Solenoid Values
Figure 4-69 Solenoid valve energized and deenergized
Figure 4-70 Solenoid-operated tank filling and emptying operation Stepper Motors Servo Motors
Figure 4-74 Closed-loop servo system
Figure 4-75 DC Brushless servo motor
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Chapter 5. Electric Motors Part 1. Motor Principle
o Magnetic field and Flux o Induction (voltage/current) and Energy conversion o Applications: Motor, Generator
Part 2. Direct Current Motor o Major components of a DC motor o Major Classifications
Permanent Magnet DC Motor Series DC Motor Shunt DC Motor Compound DC Motor
o Direction of Rotation o Motor Counter Electromotive Force (EMF) and its Effects
Example 5-1 DC Motor Ia, and EMF calculation o Speed Regulation
Example 5-2 o DC Motor Speed Control Methods o DC Motor Drives
Part 3. Three-Phase AC Motors o Speed equation: N = 120*f/P o Induction motor
Squirrel-case Induction Motor, p 114 Wound-rotor Induction Motor, p. 118
o Speed-Torque Characteristics and Applications, p. 115 NEMA Design B NEMA Design C NEMA Design D
o Motor Slip Example 5-4
o Power Factor o Dual-speed three-phase squirrel-cage single winding motor
Part 4. Single-Phase AC Motors o Split-Phase Motor, p. 121 o Split-Phase Capacitor Motor (Capacitor-start), p. 123 o Dual-Speed Capacitor-Start Motors, p.124 o Reversible Permanent-Capacitor Motor, p. 124 o Capacitor-Start/Capacitor-Run Motor, p. 124 o Shaded-Pole Motor, p. 125 o Universal Motor, p. 125
Part 5. AC Motor Drives o Variable-Frequency Drive
AC to DC Converter (rectifier) DC filter Inverter (DC to AC conversion)
Volt/Hz ratio
PWM control o Inverter Duty Motor
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Part 6. Motor Selection o Mechanical Power Rating o Current o Code Letter (NEMA Locked-Rotor Code, kVA/HP) o Design Letter o Efficiency o Energy-Efficient Motors o Frame Size o Frequency o Full-load Speed o Load Requirements
o Motor Enclosure Types o Metric Motors (50 Hz, 60 Hz: speeds)
Part 7. Motor Installation o Foundation o Mounting o Motor and Load Alignment
Direct-drive motors Coupling by means of Gears or Pulley/Belt Example 5-5
o Motor Bearings o Electrical Connections o Grounding o Conductor Size
Example 5-6 o Voltage Levels and Balance o Built-In Thermal Protection
Part 8. Motor Maintenance and Trouble Shooting
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o Motor Maintenance Schedule Periodic Inspections Brush and Commutator Care Testing Winding Insulation Keep Motor Clean Keep Motor Dry Check Lubrication Check for Excessive Heat, Noise, and Vibration Excessive Starting is a Prime Cause of Motor Failures
o Troubleshooting Motors DMM
Voltage measurement, continuity and motor winding resistance
Special type DMM includes: Capacitance measurement, frequency and temperature measurement functions
Part 1. Magnetic Contactor o Switching loads o Heater control circuits:
Delta heater load – Line current, Line voltage, three-phase power o Definite-purpose contactor
Latch coil/unlatch coil Lighting control circuit
o Contactor Assembly Shading coil
o Arc Suppression
Part 2. Contactor Ratings, Enclosures, and Solid-State Types o NEMA Ratings
NEMA contactor size guide (Figure 6-22) Example 6-1 Load Utilization Categories
Nonlinear loads
Resistive loads
Inductive loads
Capacitive loads o IEC Ratings
AC Categories DC Categories
o Contactor Enclosures Environmental factors Non-Hazardous location Hazardous Location
o Solid-State Contactor Silicon Controlled Rectifier SCR testing circuit Dual SCR for AC load Solid-state contactor digital control
Part 3. Motor Starters o Magnetic Motor Starters
Manufacturer-installed control wiring Figure 6-31 Magnetic motor starter
o Motor Overcurrent Protection Figure 6-33 Magnetic motor starter with separated mounted start-stop
pushbutton station Figure 6-34 Major functional blocks for motor operation
o Motor Overload Relays o Thermal Overload Relays o Full-load amperage (FLA) of the motor and the motor starter size o Dual-Element Fuses o NEMA and IEC Symbols
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Chapter 7. Relays
Part 1. Electromechanical Control Relays o Relay theory of operation o Relay control circuits o Relay applications
Using a relay to control a high current load with a low-current transistor circuit Diode, Transistor
o Relay styles and specifications
Part 2. Solid-State Relays o Solid-state relay operation o Specifications o Switching controls
Zero voltage crossing o Three-phase Multiple-pole SSR connections