Motor Controls Training


Class Information
Tooling U-SME classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and will take approximately one hour to complete.
Class Name:AC Motor Applications 240
Description:This class describes the common parts of AC motors as well as different types and their applications, maintenance, and troubleshooting concerns.
Prerequisites: 460200 
Difficulty:Intermediate
Number of Lessons:15
Language:English, Spanish
 
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Class Outline
  • Objectives
  • AC Motors
  • Pros and Cons of AC Motors
  • AC Generators
  • AC Motor Components
  • Types of AC Motors
  • Single-Phase Motors
  • Shaded-Pole Motors
  • Split-Phase Motors
  • Capacitor Motors
  • Three-Phase Motors
  • Squirrel Cage and Wound Rotors
  • AC Motor Maintenance
  • Troubleshooting AC Motors
  • Summary
  
Class Objectives
  • Describe factors that influence AC motor use.
  • Describe the characteristics of AC motors.
  • Explain how an AC generator works.
  • Identify common AC motor components.
  • Distinguish between induction and synchronous motors.
  • Distinguish between different types of single-phase motors.
  • Describe how a shaded-pole motor works.
  • Describe how a split-phase motor works.
  • Describe how a capacitor motor works.
  • Describe how a three-phase motor works.
  • Distinguish between squirrel cage and wound rotors.
  • Describe methods used to properly maintain AC motors.
  • Describe common troubleshooting problems for AC motors.

Class Vocabulary

Vocabulary TermDefinition
AC motor A type of electric motor that runs on alternating current. AC motors are more commonly used in industry than DC motors but do not operate well at low speeds.
alternating current Current that regularly reverses the direction of its flow in a repeating, cyclical pattern.
armature The part of a motor or generator in which a current is induced by a magnetic field. The armature usually consists of a series of coils or groups of insulated conductors surrounding a core of iron.
bearing A friction-reducing device that allows one moving part to glide past or rotate within another moving part.
brush A device found inside a generator that is used only in pairs to transfer power from a rotating object. Brushes rest on the commutator of a DC motor.
capacitor An electrical device that stores energy and releases it when needed. A capacitor gives a single-phase motor more torque but has a limited life.
capacitor motor A single-phase motor with a running winding, starting winding, and a capacitor. Capacitor motors have more torque than other single-phase motors.
capacitor start-and-run motor A type of capacitor motor that uses two capacitors, one for starting the motor, and one that remains in the circuit while the motor is running.
capacitor-run motor A type of capacitor motor that has a capacitor and starting winding connected in series at all times.
capacitor-start motor A single-phase motor with a capacitor. The capacitor gives the motor more starting torque.
centrifugal switch A type of switch that operates using the centrifugal force created from the rotating shaft. The centrifugal switch activates and de-activates depending on the speed of the motor.
direct current A current formed when electrons flow in one continuous direction.
dual voltage motor A type of three-phase motor that operates on two voltage levels. Dual voltage motors allow the same motor to be used with two different power line voltages.
efficiency losses A measure of the energy output versus the amount of input energy. The output energy is typically less than the input energy.
electric motor A machine that converts electricity into mechanical energy or motion. An electric motor is a common power source for a mechanical system.
electromagnetic induction The process in which current is induced in a magnetic field using a current-carrying coil. An AC generator produces a current through electromagnetic induction.
endbell The cap at the end of the motor that houses the rotor bearing.
field winding The conducting wire connected to the armature that energizes the pole pieces. Field windings are connected in series or parallel.
generator A device that converts mechanical energy into electrical energy by magnetic induction.
grounded Safely connected to a neutral body, like the earth, which can absorb a stray electrical charge.
induction motor A type of AC motor that uses electrical current to induce rotation in the coils.
magnet A device or object that attracts iron and produces a magnetic field.
magnetic flux The area in and around a magnet that exhibits the powers of attraction and repulsion. Rotating an armature through lines of magnetic flux induces AC.
motor nameplate A plate attached to a motor that displays all of the motor's information.
output shaft The rotating part on the the AC motor that holds the rotor and allows it to turn.
phase displacement The separation of the three phases in a three-phase motor. The windings are spaced 120° apart.
reactance The resistance to the flow of alternating current due to inductance.
resistance The opposition to current flow. Electricity flows in the path of least resistance.
rotor The rotating part of a motor.
running winding Heavy, insulated copper wire in a single-phase motor that receives the current for running the motor. The running winding remains connected when the starting winding is disconnected.
secondary winding The second winding that current passes through in a transformer. The secondary winding contains fewer, but thicker wires that are wrapped into a coil.
shaded-pole motor A single-phase motor that is 1/20 HP or less and is used in devices requiring low torque.
sine wave The most common type of AC waveform. A sine wave consists of 360 electrical degrees and is produced by rotating machines.
single voltage motor A type of three-phase motor that operates on only one voltage level. Single voltage motors are limited to having the same voltage as the power source.
single-phase motor A type of motor with low horsepower that operates on 120 or 240 volts. Single-phase motors are often used in residential appliances like washing machines and air conditioners.
slip The difference between a motor's synchronous speed and its speed at full load. Percent slip is a way to measure the speed performance of an induction motor.
slip ring A conductive device attached to the end of a generator rotor that conducts current to the brushes. Slips rings are also used in AC wound rotor motors.
split-phase motor A single-phase motor that consists of a running winding, starting winding, and centrifugal switch. The reactance difference in the windings creates separate phases, which produce the rotating magnetic field that starts the rotor.
squirrel cage rotor A type of three-phase AC rotor that is constructed by connecting metal bars together at each end. It is the most common AC rotor type.
starting winding Fine, insulated copper wire in a single-phase motor that receives current in the motor at startup. When the motor reaches 60-80% of th full load, the starting winding is disconnected and the running winding remains in the circuit.
stator The stationary part of a motor.
stepped down In electricity, a phrase used to describe voltage adjustment. To step down voltage means to decrease voltage.
stepped up In electricity, a phrase used to describe voltage adjustment. To step up voltage means to increase voltage.
synchronous motor A constant-speed AC motor that does not use induction to operate. A synchronous motor needs DC excitation to operate.
thermal switch A type of switch often found in split-phase motors that signals that the motor may overheat.
three-phase motor A motor with a continuous series of three overlapping AC cycles offset by 120 degrees. Three-phase power is used for all large AC motors and is the standard power supply that enters homes and factories.
torque A force that produces rotation.
transform To increase or decrease the voltage in a circuit.
wound rotor A type of three phase rotor that contains windings and slip rings. This motor type permits control of rotor current by connecting external resistance in series with the rotor windings.