EN-3111 - Electrical Machines

TOPIC - DC electric circuits

• Solves series and parallel circuits using ohm's law, and Kirchoff's voltage and current laws.
• Defines fundamental units including:
  • voltage
  • amperes
  • ohms
  • watts
  • kilowatt hours.
• Explains grounded and ungrounded circuits and common circuit faults.
• Uses electrical instruments to find circuit faults, and conduct electrical trouble-shooting.

31A3.2.2
31A3.1.2

TOPIC - Batteries

• Defines and explain primary and secondary batteries including the principle of specific gravity.
• Explains the advantages and disadvantages of common battery types.

31A3.2.2

TOPIC - Electromagnetism

• Explains the principles of electromagnetism, magnetomotive force, saturation and residual magnetism
• Uses the right hand rule for current carrying conductors and the right hand rule for coils.
• Defines fundamental magnetic quantities including:
  • webers
  • permeability
  • teslas
  • reluctance
  • magnetomotive force.

31A3.2.2
31A3.2.1

TOPIC - Electromagnetic induction

• Explains the principles of electromagnetic induction including mutual induction and self-induction.
• Uses Fariday's and Lenz's laws to determine the magnitude and direction of induced EMF.

31A3.2.2
31A3.2.1

TOPIC - Direct current generators

• Explains the construction of DC Generators including the
  • field windings
  • armature
  • commutator
  • interpoles
  • brushes
• Applies the generator principle to understand the operation of series, shunt, and compound wound DC generators.
• States the voltage regulation characteristics of the above types of DC Generators.

31A3.2.1

TOPIC - Direct current motors

• Explains the construction of DC Motors including the:
  • field windings
  • armature
  • commutator
  • interpoles
  • brushes
• Applies the motor principle to series, shunt, and compound wound DC motors.
• States the torque and speed characteristics of the above DC motors.

31A3.2.1

TOPIC - DC motor controllers and starters

• Explains the operation of DC Motor Controllers, including the principle of overload protection, low voltage protection and low voltage release.
• Explains the use of relays and contactors in motor control.
• Explains the principle of starting resistance and speed control for DC Motors.

31B1.1.3

TOPIC - Alternating current circuits

• Explains an alternating electromotive force and the concept of frequency, capacitance, capacitive reactance, inductance, and inductive reactance and their effect on the impedance of a circuit.
• Represents current and voltage as phasors having magnitude and phase angle and performs addition and subtraction of these quantities.

31A3.2.2

TOPIC - Single phase circuits

• Defines circuit power, KVA, KVAR, and power factor as well as current, voltage, and power relations in series and parallel circuits having resistance, inductance, and capacitance.
• Defines circuit resonance and power factor correction.
• Solves single phase circuit problems.

31B1

TOPIC - Three phase circuits

• Explains generation of three phase EMF, and voltage, current, and power relations in delta and wye connections.
• Solves three phase circuits problems.

31A3.2.2

TOPIC - Transformers

• Explains transformer theory under load and no load.
• Defines transformer construction, ratings, applications, losses, single phase connections and three phase connections.

31A3.2.2

TOPIC - Alternating current generators

• Explains the construction of AC generators, methods of field excitation, voltage regulation, load sharing, hunting, ratings, losses, and efficiency.
  • 2.Demonstrates the correct procedure for safely paralleling AC generators.

31A3.2.1
31B1.1.1

TOPIC - Three phase induction motors

• Explains the construction of a three phase induction motor including:
  • rotating magnetic field
  • synchronous speed
  • rotor speed
  • slip
  • rotor frequency
  • torque and speed characteristics
  • effect of load on power factor
• Describes the operation of squirrel cage, double squirrel cage and wound rotor motors.
• Demonstrates the correct methods of starting AC motor drives.

31A3.2.1

TOPIC - Three phase synchronous motors

• Explains operation of the three phase synchronous motor, including:
  • starting methods
  • methods of field excitation
  • synchronous speed
  • effect of load
  • torque angle
  • principle of over and under excitation
  • power factor correction
  • efficiency
  • and ratings.
• Demonstrates the correct methods of starting AC synchronous motor drives.

31A3.2.1

TOPIC - Single phase motors

• Describes the construction, operation, and applications of AC series motors, single phase induction motors, and single phase synchronous motors.
• Explains motor starting principles including split phase starting, resistance starting, capacitor starting, and shaded pole starting.

31A3.2.1

LAB - Electrical instruments and wiring methods

• Uses electrical instruments to measure voltage, current, and resistance in AC and DC circuits.
• Verifies Ohm's Law for D.C. circuits.
• Uses basic electrical troubleshooting techniques such as voltage and continuity checks to identify circuit problems.

31A3.1.2
31A3.3.1
31B1.4.1

LAB - Residential wiring

• Understands the 3 wire, single phase, 120/240 volt residential wiring arrangement, including pertinent code requirements.
• Connects residential switches and receptacles in a safe and workmanlike manner.
• Checks work for continuity using a multimeter.

31A3.1.2
31B1.4.1

LAB - DC generators

• Determines how the direction of rotation and the field polarity affect the armature polarity of a DC generator.

31A3.2.1

LAB - DC motors

• Operates a DC motor and measures current, voltage, and amperage
• Safely deenergize, lock-out and tag-out motor for repair
• Disassembles a DC motor, removes all the field poles.
• Tests for ground faults with a megohmmeter.
• Tests for opens with a multimeter.
• Tests for armature shorts with a growler.
• Reassembles the motor and runs it.

31A3.1.1
31C1.2.1
31A3.2.1
31A3.1.2
31B1.4.1

LAB - Paralleling DC generators

• Places a DC generator on line and studies generator characteristics including raising voltage and balance coil adjustments.
• Places a second generator on line in parallel, and balances kW loads.
• Studies the motor reaction of a generator.
• Remove a generator from the line.

31B1.2.1

LAB - Low voltage protection AC motor controllers

• Dissassembles an LVP motor controller and studies its concepts including the relay, the overload mechanism, and the holding contacts.
• Reassembles, wires, and tests the controller.

31C1.3.2

LAB - AC Motor Characteristics

• Determines the relations between torque, speed, current, power, power factor and efficiency of a three phase induction motor.

31A3.2.1

LAB - Low voltage release AC motor controllers

• Dissassembles an LVR motor controller and studies its concepts including the relay, the overload mechanism, and the shading coils.
• Reassembles, wires and tests the controller.

31C1.3.2
31B1.4.1

LAB - Trouble shooting AC motor controllers

• Wires an across-the-line three phase reversing motor controller.
• Uses electrical test equipment to trouble shoot various circuit faults.

31B1.4.1
31A3.1

LAB - Time on-delay relays

• Connects a three phase across the line LVP motor controller with a time on-delay relay.
• Studies the operation of the controller.

31C1.3.2

LAB - Sychronizing AC generators

• Parallels three phase generators using synchronizing lights and a sychroscope.
• Balances the load between the generators.
• Balances the power factor between the generators.
• Understands the relationships between field current, prime mover speed, alternator voltage and frequency.
• Observes the effect of adding load to an AC generator in parallel.
• Removes the generator from the bus.

31B1.2.1

LAB - Time off-delay relays

• Wires a three phase across-the-line LVP motor controller with a time off-delay relay.
• Studies the operation of the controller.

31C1.3.2