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Icehouse:
Electricity Unit 4 - Troubleshooting Components
 

 Lesson 1 - Test Equipment (Part 1)
 Objectives:
 
* Describe the basic operation of the d’Arsonval meter movement.
* Explain the difference between analog and digital measuring instruments.
* Distinguish between voltmeters, ammeters, ohmmeters, and multimeters, and describe the operational principles of each.
* Explain how the sensitivity of a voltmeter is calculated.
* Describe how various electrical meters are used to measure resistance, voltage, and current, and to check for continuity.
* Demonstrate how clamp-on ammeters are used.
* Describe the basic operation of a Wheatstone bridge, and explain how it can be configured to act as a resistance bridge or a capacitance bridge. Lesson 2 - Test Equipment (Part 2) Objectives:
 
* Explain the operation of a wattmeter.
* Demonstrate how to read a watt-hour meter.
* Describe how to determine the power factor of a circuit by using a power factor meter.
* Describe how a varmeter can be used in correcting power factor problems.
* Explain the purposes and use of various instrument transformers.
* Explain the operation of megohmmeter.
* Explain the purpose and use of various recording instruments.
* Describe how a compressor analyzer can be used in troubleshooting. Lesson 3 - Resistors Objectives:
 
* Observe the proper safety precautions when taking ohmmeter readings.
* Select the best range for a particular resistance measurement.
* ”zero adjust” an analog ohmmeter.
* Determine the resistance values of various types of resistors.
* Use an ohmmeter to test resistors, potentiometers, rheostats, bleeder resistors, thermistors, PTC start-assist devices, and diodes. Lesson 4 - Capacitors Objectives:
 
* Observe the proper safety precautions when taking capacitance readings.
* Explain the differences between start and run capacitors.
* Discharge a capacitor safely.
* Describe the four main problems or conditions that identify a faulty capacitor.
* Describe the operation of various types of instruments used for testing capacitors. Lesson 5 - Relays, Contactors, and Starters Objectives:
 
* List common causes of relay failure.
* Describe the physical indications that identify defective relays and contactors.
* Explain how to test pilot-duty relays and line-duty relays.
* Explain how to test contactors and starters.
* Explain how to test potential relays and current relays.
* Explain how to test time-delay relays. Lesson 6 - Transformers Objectives:
 
* Describe the conditions that cause transformers to fail.
* Describe the physical indications that identify defective transformers.
* Explain the differences between residential and commercial transformers.
* Determine the current-carrying capacity of a control transformer.
* Explain how to test different types of transformers.
* Define open circuit voltage (OCV).
* Test continuity between the primary and secondary windings of a transformer. Lesson 7 - Thermostats Objectives:
 
* Describe the basic construction operation of a bimetal mechanical thermostat.
* Explain the concept of anticipation.
* Describe some of the physical indications that identify defective thermostats.
* Test a mechanical thermostat with a voltmeter and/or ohmmeter.
* Set an adjustable anticipator.
* Calibrate a mechanical thermostat.
* Explain the differences between residential and commercial thermostats.
* Identify common problems that affect electronic thermostats, and explain basic troubleshooting techniques. Lesson 8 - Motors Objectives:
 
* List the basic types of motors used in the HVACR industry.
* Describe some of the visual indications that identify defective motors.
* Explain the difference between fractional-horsepower motors and integral-horsepower motors.
* Determine the speed and rotation of a motor.
* Use appropriate test instruments to troubleshoot various types of motors and their associated starting circuits.
* Describe some of the causes of overheating in electric motors.
* Explain what causes single phasing in a three-phase motor.
* Calculate voltage and current imbalances in three-phase motors.
* Describe basic motor replacement procedures.
* Read a motor nameplate.
* Use NEMA data to determine motor frame sizes and dimensions. Lesson 9 - Hermetic Compressors Objectives:
 
* Explain the differences among open, semi-hermetic, and hermetic compressors.
* Describe the various starting methods used for single-phase hermetic compressors.
* Explain the function and operation of overload protection devices use in hermetic compressors.
* Check a single-phase hermetic compressor for proper resistance, voltage, and current readings.
* Identify the terminals of a single-phase hermetic compressor, even if they are unmarked.
* Check a three-phase hermetic compressor for proper resistance, voltage, and current readings.
* Calculate voltage and current imbalances in three-phase hermetic compressors. Lesson 10 - Semi-Hermetic Compressors Objectives:
 
* Explain the differences between hermetic and semi-hermetic compressors.
* Describe the various starting methods used for single-phase semi-hermetic compressors.
* Check a single-phase semi-hermetic compressor for proper resistance, voltage, and current readings.
* Identify the terminals of a single-phase semi-hermetic compressor, even if they are unmarked.
* Check a three-phase semi-hermetic compressor for proper resistance, voltage, and current readings.
* Calculate voltage and current imbalances in three-phase semi-hermetic compressors.
* Explain what causes single phasing in three-phase semi-hermetic compressors.
* Explain the function and operation of overload protection devices use in semi-hermetic compressors. Lesson 11 - Electronic Components Objectives:
 
* Explain how to test diodes, both with an analog meter and a digital meter.
* Explain how to test NPN and PNP transistors.
* Explain how to test silicon-controlled rectifiers (SCRs).
* Explain how to test triacs.
* Describe the effects that electrostatic discharge (ESD) can have on electronic components.
* List the precautions that you should take to prevent ESD damage when servicing electronic components.
* Demonstrate logical troubleshooting procedures when diagnosing printed circuit (PC) boards. Lesson 12 - Wiring Systems Objectives:
 
* Describe the different types of wiring systems used in the HVACR industry.
* Test single-phase residential power circuits for voltage drop, voltage imbalance, and current imbalance.
* Test three-phase commercial power circuits for voltage drop, voltage imbalance, and current imbalance.
* Define ampacity, and explain how wire sizes are selected for given applications.
* Troubleshoot low-voltage control circuits.
* Troubleshoot high-voltage ac control circuits.
* Troubleshoot direct digital control (DDC) circuits.
* Describe some of the basic problems encountered in all wiring systems

Icehouse:
Electricity Unit 5 - Troubleshooting Residential Equipment
 

 Lesson 1 - Getting Started
 Objectives:
 
* Use checklists and log sheets to record information about the equipment you service, and about the service procedures you perform.
* Identify common warning symbols used by manufactures today, and explain basic electrical safety precautions.
* Isolate a problem by performing simple electrical troubleshooting tasks in a logical order.
* Locate a faulty component by using the “hopscotch” method of troubleshooting. Lesson 2 - Reading Schematics Objectives:
 
* Read and interpret electrical schematic diagrams correctly as an aid in troubleshooting.
* Recognize and explain some of the differences between the schematics of one manufacturer and another, including wiring and terminal designations, symbol usage, component placement, and so on.
* Describe the sequence of operation for the equipment of several different manufacturers by tracing their respective wiring diagrams.
* Explain how high-voltage and low-voltage power supply information is provided on the schematics of residential and light commercial equipment. Lesson 3 - Split Systems (Part 1) Objectives:
 
* Describe appropriate electrical troubleshooting procedures for residential split systems.
* Develop a logical approach to isolating the cause of a service problem.
* Read and follow a troubleshooting flow chart. Lesson 4 - Split Systems (Part 2) Objectives:
 
* Explain some of the problems encountered with high-voltage gas heating/air conditioning systems.
* Describe appropriate electrical troubleshooting procedures for these types of residential split systems.
* Read and interpret the self-diagnostic fault codes used in some high-efficiency furnaces.
* Locate the probable causes of a service problem (e.g., the electronic thermostat, the printed circuit board, wiring difficulties, etc.). Lesson 5 - Gas Furnaces (Part 1) Objectives:
 
* Explain some of the problems encountered with several types of ignition systems and safety controls that are used with gas furnaces.
* Describe appropriate electrical troubleshooting procedures for these types of heating systems.
* Read and interpret the schematic diagrams and troubleshooting flow charts provided by the manufacturers of such equipment.
* Locate the probable cause of a service problem (e.g., the thermostat, the printed circuit board, the wiring, etc.). Lesson 6 - Gas Furnaces (Part 2) Objectives:
 
* Explain some of the problems encountered with hot surface ignition (HSI) systems.
* Describe appropriate electrical troubleshooting procedures for heating systems that use microprocessors, printed circuit boards, and self-diagnostic LEDs.
* Read and interpret the schematic diagrams and troubleshooting flow charts provided by the manufacturers of such equipment. Lesson 7 - Oil Furnaces Objectives:
 
* Explain some of the problems encountered with various types of ignition systems and safety controls that are used with oil-fired furnaces.
* Describe appropriate electrical troubleshooting procedures for these types of heating systems.
* Locate the probable cause of a service problem.
* Evaluate the performance of a cad cell.
* Use a test lamp to find a shout circuit. Lesson 8 - Electric Furnaces Objectives:
 
* Explain some common problems encountered with multistage electric furnaces.
* Describe appropriate electrical troubleshooting procedures for these types of heating systems.
* Calculate the actual air flow (in cfm) of an electric furnace.
* Calculate the temperature rise across a set of electric heaters.
* Calculate the current draw of an electric heater.
* Describe the procedure for identifying an open heater.
* Explain what is meant by “black heat.”
* Locate the probable cause of a service problem. Lesson 9 - Air-to-Air Heat Pumps Objectives:
 
* Explain some common problems encountered with air-to-air heat pump systems.
* Describe appropriate electrical troubleshooting procedures for these types of heat pumps.
* Locate the probable causes of typical service problems, including those involving defrost controls and supplemental electric heating sections.
* Explain the basic operation of a reversing valve, and describe how to diagnose a bad valve.
* Determine whether the compressor is operating in both the heating mode and the cooling mode.
* Check the operation of outdoor thermostats. Lesson 10 - Water-Source Heat Pumps Objectives:
 
* Explain some common problems encountered with water-source heat pump systems.
* Describe appropriate electrical troubleshooting procedures for these types of heat pumps.
* Locate the probable causes of typical service problems, including those involving water flow controls, changeover controls, and lockout controls.
* Explain the basic operation of a reversing valve, and describe how to diagnose a bad valve.
* Determine whether the compressor is operating in both the heating mode and the cooling mode. Lesson 11 - Electronic Air Cleaners Objectives:
 
* Describe the basic operation of an electronic air cleaner (EAC) and its high-voltage power supply.
* Explain the purpose of “doubler” rectifier circuits.
* Discuss some common problems encountered with electronic air cleaners, and describe appropriate electrical troubleshooting procedures for this type of equipment.
* Locate the probable causes of typical service problems, including those involving safety controls, ozone odors, “white dust,” noisy operation, and television interference. Lesson 12 - Humidifiers Objectives:
 
* Describe the basic operation of an evaporative humidifier, and of a steam humidifier.
* Discuss some common problems encountered with humidifiers, and describe appropriate electrical troubleshooting procedures for this type of equipment.
* Locate the probable causes of typical service problems, including those involving humidistats, solenoid valves, float switches, and safety controls.
* Diagnose “too much humidity” and “not enough humidity” complaints. Lesson 13 - Electrical Troubleshooting Reference Guide This Lesson is intended to serve as a general reference guide for the electrical troubleshooter.  It contains a broad range of technical information, including various tables, charts, symbols, and mathematical equations, as well as service tips and reminders designed to help technicians increase their productivity on the job

Icehouse:
The above is required knowledge to pass the RSES CM (Certified Mechanic) Electricity which is excellent for all tests.

Icehouse:

Icehouse:
  PSC Motors - Schematics

Permanent Split Capacitor (PSC) Motors' Schematics

Attached are several Schematics describing the following type Single Phase Induction Motors:

Split-Phase Induction; Permanent Split Capacitor (PSC)

To discuss these items, please refer to the following Thread in the Electrical Theory and Applications Section:

Single Phase Induction Motor

Let me know if you have suggestions, questions or comments.

Scott

*** PLEASE NOTE ***
These Drawings do not include Speed Control; only Start/Stop + Forward / Reverse control.
For Speed Control PSC Schematics, please refer to the Technical Reference Section's "Menu".
Search for the link entitled: "Split-Phase 1Ø Motors: Series 3"


*** Drawings Uploaded 06/05/2008 ***

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*** NOTE ***

Either of the Two (2) "AC-IN" leads may be the System's Grounded ("Neutral") Conductor - for an L-N Circuit (i.e.: 120V, 277V);
or they may both be Ungrounded ("Hot") Conductors - for an L-L Circuit (i.e.: 208V, 240V, 480V).


*** BASIC OPERATION PRINCIPLES ***

This Motor is a Single Phase Squirrel-Cage Induction Motor: Split-Phase, Permanent Split Capacitor.

The Motor's Auxiliary Winding has a low value Capacitor in Series between the Winding and the "Opposite" side of the AC Circuit.

There is no Centrifugal Start Switch in series with the Auxiliary Winding / Capacitor, as would be normal with any other Split-Phase Motors - with the exception of the Cap. Start / Cap. Run Motor, or the Shaded Pole Motor.

The Auxiliary Winding + Capacitor remain connected to the AC Circuit thruout the entire operation of the Motor.

Starting Torque is very low, but Pullout Torque is not so bad!

Speed control of these Motors may be easilly achieved by reducing the input Voltage - either by an external means, or by an intregral Autotransformer wound into the Motor's Windings.

The Speed of the Rotor will be a result of the required True Power (Wattage) needed to drive the load on the shaft, and falling just below a "Slip Frequency" point.

*** STARTING PROCEDURES ***

To get the 1 Phase Motor's Rotor to begin spinning (as opposed to just sitting still), one "Side" of the Main Winding's Magnetic Field must be reduced in intensity. This is achieved by adding the "Auxiliary" (or "Start") winding into the Motor's Circuitry.

At Start, without the Aux. winding, the Main Winding produce an equal Field across its self + the rotor, which results in no Induced VARs (Reactive Power) into the Rotor - so the rotor just sits still.

With the Aux. Winding included to the Circuit, one "Side" of the Main Winding's Field is reduced, which allows for VARs to be Induced into the Rotor - thereby makes the Rotor start to spin.

The Rotor turns toward the "Side/End" of the Main Winding with the larger Field.

Speed increases to the point where the Rotor can develope the needed Torque / Horsepower, by drawing the necessary level of True Power (Wattage) from the Supply (Watage equates to output HP), along with the needed VARs (Reactive Power, or Volt-Amps Reactive).

Both of these Powers are contained in the "Apparent Power" (VA, or Volt-Amps)

Since the Single Phase 2 Wire Circuit has no "Polarity", reversing only the incoming leads will not reverse the Rotor's Direction.

The way the Rotor's Direction is changed is by "Reversing The Relative Polarity" of the Auxiliary Winding, as viewed by the "Relative Polarity" of the Main Winding (the Main Winding's Relative polarity does not get changed).

When this is done, the Magnetic field is reduced on the opposite end of the main Winding, so the Rotor begins to spin towards the "End" of the Main Winding with the larger Magnetic Field.
As a result, the Rotor spins in the opposite direction.

==============================================================================================

==============================================================================================

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FIGURE #1-1: BASIC PSC MOTOR CONNECTIONS:
DIRECTION = FORWARD

This Drawing shows the Permanent Split Capacitor Motor (hereafter referred to as "PSC Motor"), with Basic connection scheme for Forward Rotation Direction.


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FIGURE #1-2: BASIC PSC MOTOR CONNECTIONS:
DIRECTION = REVERSE

This Drawing shows the PSC Motor, with Basic connection scheme for Reverse Rotation Direction.


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FIGURE #1-3: BASIC PSC MOTOR CONNECTIONS:
DIRECTION = REVERSE

This Drawing shows what Fig. 1-2 actually looks like to the Rotor.

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FIGURE #2-1: DIRECTIONAL PSC MOTOR CONNECTIONS - SWITCH CONTROL:
DIRECTION = FORWARD

This Drawing shows the PSC Motor with SPDT Switches used for Forward / Reverse of the Motor.

Switches are thrown to position for _FORWARD_ Rotation.

"On/Off" Switch controls Motor's input, so if this Switch is Open (Off), the Motor will not run.

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FIGURE #2-2: DIRECTIONAL PSC MOTOR CONNECTIONS - SWITCH CONTROL:
DIRECTION = REVERSE

This Drawing shows the PSC Motor with SPDT Switches used for Forward / Reverse of the Motor.

Switches are thrown to position for _REVERSE_ Rotation.

"On/Off" Switch controls Motor's input, so if this Switch is Open (Off), the Motor will not run.

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FIGURE #3-1a: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = N/A (MOTOR AT REST)

*** MOTOR CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "REST" (Motor is Off).

See Fig.# 3-1b below, for Control Schematic

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FIGURE #3-1b: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = N/A (MOTOR AT REST)

*** CONTROL CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "REST" (Motor is Off).

See Fig.# 3-1a above, for Control Schematic

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FIGURE #3-2a: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = FORWARD

*** MOTOR CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "FORWARD".

See Fig.# 3-2b below, for Control Schematic

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FIGURE #3-2b: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = FORWARD

*** CONTROL CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "FORWARD".

See Fig.# 3-2a above, for Control Schematic

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FIGURE #3-1a: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = REVERSE

*** MOTOR CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "REVERSE".

See Fig.# 3-3b below, for Control Schematic

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FIGURE #3-3b: DIRECTIONAL PSC MOTOR CONNECTIONS - CONTACTOR CONTROLLED:
DIRECTION = REVERSE

*** CONTROL CIRCUITRY ***

This Drawing shows the PSC Motor with Contactors used for Forward / Reverse of the Motor.

Control logic State = "REVERSE".

See Fig.# 3-3a above, for Control Schematic

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