Generac Power Systems CorePower, CorePower 6/7 kW Repair Manual
DIAGNOSTIC
REPAIR
MANUAL
®
CorePower Home Standby Generator
MODELS:
6/7 kW
STANDBY GENERATORS
Foreword
SAFETY
Throughout this publication, DANGER, WARNING, and CAUTION
blocks are used to alert the mechanic to special instructions
concerning a particular service or operation that might be
hazardous if performed incorrectly or carelessly. Observe them
carefully. Their definitions are as follows:
After this heading, read instructions that, if not strictly complied
with, will result in serious personal injury, including death.
After this heading, read instructions that, if not strictly complied
with, could result in serious personal injury, including death.
After this heading, read instructions that, if not strictly complied
with, might result in minor or moderate injury.
Four commonly used safety symbols accompany the DANGER,
WARNING and CAUTION blocks. The type of information each
indicates follows:
This symbol points out important safety information that,
if not followed, could endanger personal safety and/or
property of others.
This symbol points out potential explosion hazard.
This symbol points out potential fire hazard.
This symbol points out potential electrical shock hazard.
These “Safety Alerts” alone cannot eliminate the hazards that
they signal. Strict compliance with these special instructions
plus “common sense” are major accident prevention measures.
READ THIS MANUAL THOROUGHL Y
This SERVICE MANUAL has been written and published by
Generac to aid our dealers' technicians and company service
personnel when servicing the products described herein.
It is assumed that these personnel are familiar with the servicing
procedures for these products, or like or similar products
manufactured and marketed by Generac, and that they have
been trained in the recommended servicing procedures for these
products, including the use of common hand tools and any
special Generac tools or tools from other suppliers.
Generac could not possibly know of and advise the service
trade of all conceivable procedures by which a service might
be performed and of the possible hazards and/or results
of each method. We have not undertaken any such wide
evaluation. Therefore, anyone who uses a procedure or tool
not recommended by Generac must first satisfy themselves that
neither his nor the products safety will be endangered by the
service procedure selected.
All information, illustrations and specifications in this manual
are based on the latest product information available at the time
of publication.
When working on these products, remember that the electrical
system and engine ignition system are capable of violent and
damaging short circuits or severe electrical shocks. If you
intend to perform work where electrical terminals could be
grounded or touched, the battery cables should be disconnected
at the battery.
Any time the intake or exhaust openings of the engine are
exposed during service, they should be covered to prevent
accidental entry of foreign material. Entry of such materials will
result in extensive damage when the engine Is started.
During any maintenance procedure, replacement fasteners must
have the same measurements and strength as the fasteners
that were removed. Metric bolts and nuts have numbers
that indicate their strength. Customary bolts use radial lines
to indicate strength while most customary nuts do not have
strength markings. Mismatched or incorrect fasteners can
cause damage, malfunction and possible injury.
Note: Special Notes appear in bold type throughout this
publication. While not pertaining to safety, they emphasize
procedures, circumstances or specifications that require
special attention.
REPLACEMENT PARTS
When servicing this equipment, it is extremely important that all
components be properly installed and tightened. If improperly
installed and tightened, sparks could ignite fuel vapors from fuel
system leaks.
SAFETY .............................................................................. 2
Read This Manual Thoroughly
Specifications
......................................................................4
............................................. 2
Generator ............................................................... 4
Engine .................................................................... 4
Fuel Consumption
Major Features
................................................... 5
........................................................ 5
PART 1 – GENERAL INFORMATION ......................................9
Section 1.1 – Generator Basics ......................................... 10
Introduction
Parts
.......................................................... 10
.................................................................... 10
Generator Identification ......................................... 10
Section 1.2 – Measuring Electricity ...................................11
.................................................................. 11
Meters
The VOM
.............................................................. 11
Measuring AC Voltage ...........................................11
Measuring DC Voltage ...........................................11
Measuring AC Frequency ...................................... 11
Measuring Current ................................................ 12
Measuring Resistance ........................................... 12
Electrical Units ...................................................... 13
Ohm’s Law ........................................................... 13
Section 1.3 – Preparation Before Use ................................ 14
Introduction .......................................................... 14
Fuel Consumption ................................................. 14
Reconfigure the fuel system .................................. 14
Section 1.4 – Operating Instructions ................................. 16
Control Panel ........................................................ 16
User Interface ....................................................... 16
Automatic Operation ............................................. 16
Manual Operation.................................................. 16
Section 1.5 – Automatic Operating Parameters .................. 18
Introduction .......................................................... 18
Utility Failure ......................................................... 18
Cranking ............................................................... 18
Cranking conditions .............................................. 18
Load Transfer Parameters ..................................... 18
Section 1.6 – General Maintenance ................................... 20
Introduction .......................................................... 20
Engine Oil ............................................................. 20
Engine Oil Recommendations ................................ 20
Air Filter ................................................................ 20
Spark Plugs .......................................................... 20
Visual Inspection .................................................. 20
Corrosion Protection ............................................. 20
Valve Clearance .................................................... 20
Battery ................................................................. 21
Section 1.7 – General Troubleshooting .............................. 22
Introduction
Recommended Tools
.......................................................... 22
............................................ 22
Troubleshooting Reminders and Tips ..................... 22
Connectors ........................................................... 22
PART 2 – AC Generators
Section 2.1 – Description and Components
....................................................23
....................... 24
Introduction .......................................................... 24
Engine-Generator Drive System ............................. 24
Alternator Assembly
Brush Holder and Brushes
............................................. 24
.................................... 24
Other AC Generator Components .......................... 25
Section 2.2 – Operational Analysis .................................... 26
................................................................. 26
Startup
On-Speed Operation
.............................................. 26
Field Excitation ...................................................... 26
AC Power Winding Output ..................................... 26
Section 2.3 – Troubleshooting Flowcharts ......................... 27
Introduction .......................................................... 27
Problem 1 – Generator Produces Zero Voltage
or Residual Voltage ............................................... 27
Problem 2 – Generator Produces
Low Voltage at No-Load ........................................28
Problem 3 – Generator Produces
High Voltage at No-Load .......................................29
Problem 4 - Voltage and Frequency
Drop Excessively When Loads Are Applied ............ 29
Section 2.4 – Diagnostic Tests .......................................... 30
Introduction .......................................................... 30
Safety ................................................................... 30
AC Troubleshooting............................................... 30
Test 1 – Check Main Circuit Breaker ...................... 30
Test 4 – Fixed Excitation /Rotor Amp Draw Test ..... 30
Test 6 – Resistance Check of Rotor Circuit ............ 32
Test 7 – Check Brushes and Slip Rings ................. 32
Test 9 – Test the Stator ......................................... 33
Test 10 – Test Rotor Assembly .............................. 34
Test 11 – Check AC Output Voltage ....................... 34
Test 12 – Check AC Output Frequency ................... 34
Test 13 – Adjust Engine Governor ......................... 35
Test 14 – Adjust Voltage Regulator ....................... 35
Test 15 – Check for Overload Condition ................. 36
Test 16 – Check Voltage and
Frequency Under Load ........................... 36
PART 3 – Transfer Switch ..................................................37
Section 3.1 – Description and Components ....................... 38
General ................................................................. 38
Enclosure ............................................................. 38
EZ Transfer Operator ............................................. 38
Fuse Holder .......................................................... 38
Page 1
Page 1
Section 3.2 – Operational Analysis .................................... 39
Utility Voltage Present
Transfer to Standby
........................................... 39
............................................... 39
Transfer to Utility ................................................... 39
Section 3.3 – Troubleshooting Flowcharts ......................... 41
Introduction
.......................................................... 41
Problem 10 – In Automatic Mode,
No Transfer to Standby
......................................... 41
Problem 11 – In Automatic Mode, Generator
Starts When Loss of Utility Occurs, Generator
Shuts Down When Utility Returns But There is No
Retransfer To Utility Power OR Generator Transfers
to Standby During Exercise or in Manual Mode ...... 41
Problem 12 – Blown F1 or F2 Fuse ........................42
Problem 13 – Blown T1 Fuse
................................ 42
Problem 14 – Unit Starts and Transfer Occurs
When Utility Power is On
....................................... 42
Section 3.4 – Diagnostic Tests .......................................... 43
Introduction .......................................................... 43
Safety ................................................................... 43
Transfer Switch Troubleshooting ..........................43
Test 27 – Check Generator Voltage at
Transfer Switch ...................................... 43
Test 28 – Test Transfer Operator ............................43
Test 29 – Check 15B/194 Circuit .......................... 43
Test 30 – Check Wire 23 Circuit ............................ 44
Test 32 – Check Fuses F1 and F2 .......................... 44
Test 33 – Check N1 and N2 Wiring ........................ 45
Test 35 – Check Fuse F3 ...................................... 45
Test 36 – Check T1 Wiring .................................... 45
Test 38 – Check N1 and N2 Voltage ...................... 46
Test 39 – Check Utility Sense Voltage .................... 46
Test 40 – Check Utility Voltage at Transfer Switch .. 46
Test 41 – Check Utility Sensing Voltage
at the Controller ..................................... 46
PART 4 – Engine/DC Control ..............................................49
Section 4.1 – Description and Components ....................... 50
General ................................................................. 50
Terminal Strip / Interconnection Terminal ............... 50
Controller ............................................................. 50
Auto-Off-Manual Switch ........................................ 50
7.5 Amp Fuse ....................................................... 50
Alarms ................................................................. 52
Clear Alarms ......................................................... 52
Warnings .............................................................. 52
Section 4.3 – Operational Analysis .................................... 54
Utility Source Available .......................................... 54
Utility Failure and Engine Cranking ......................... 55
Utility Failure and Engine Running ..........................56
Section 4.4 – Troubleshooting Flowcharts ......................... 57
Problem 20 – Engine Will Not Crank When
Utility Power Source Fails
...................................... 57
Problem 21 – Engine Will Not Crank When
AUTO-OFF-MANUAL Switch is Set to “MANUAL”
... 57
Problem 22 – Engine Cranks but Won’t Start ......... 58
Problem 23 – Engine Starts Hard and
Runs Rough / Lacks Power / Backfires .................. 59
Problem 24 – Shutdown Alarm/Fault Occurred
Problem 25 – 7.5 Amp Fuse (F1) Blown
...... 60
................ 61
Problem 26 – Generator Will Not Exercise ............. 61
Problem 27 – No Battery Charge ........................... 61
Section 4.5 – Diagnostic Tests
Introduction
.......................................................... 62
.......................................... 62
Safety ................................................................... 62
Engine/DC Troubleshooting .................................. 62
Test 52 – Check Position Of
Auto-Off-Manual Switch ....................... 62
Test 53 – Try a Manual Start ................................ 63
Test 54 – Test Auto Operations .............................. 63
Test 55 – Check 7.5 Amp Fuse.............................. 63
Test 56 – Check Battery ........................................ 63
Test 57 – Check Wire 56 Voltage ........................... 65
Test 58 – Test Starter Contactor ............................ 65
Test 59 – Test Starter Motor .................................. 66
Test 60 – Check Fuel Supply and Pressure ............ 67
Test 61 – Check Circuit Board Wire 14 Output ....... 68
Test 62 – Check Fuel Solenoid .............................. 69
Test 63 – Check Choke Solenoid ........................... 69
Test 64 – Check for Ignition Spark ......................... 69
Test 65 – Check Spark Plugs ................................ 70
Test 66 – Check Engine / Cylinder Leak
Down Test / Compression Test ............... 71
Cylinder Leak Down Test ........................ 71
Check Compression ............................... 71
Test 67 – Check Ignition Coil ................................. 72
Test 68 – Check Oil Pressure Switch And Wire 86 . 72
Test 69 – Check High Oil Temperature Switch ........ 73
Test 70 – Check and Adjust Valves ........................ 74
Test 71 – Check Wire 18 Continuity ....................... 75
Test 72 – Test Exercise Function ........................... 75
Test 73 – Test Cranking and Running Circuits ........ 75
Test 74 – Test Run Circuit ..................................... 76
Test 75 – Test Crank Circuit .................................. 76
Test 76 – Check Battery Charger Supply Voltage.... 76
Test 77 – Check Battery Charger Output Voltage .... 77
Test 78 – Check Wire 0/15B.................................. 77
Test 79 – Check Shutdown Wire ........................... 77
Page 2
PART 5 – Disassembly .......................................................81
Section 5.1 – Major Disassembly
Section 5.2 – Exploded Views
...................................... 82
........................................... 90
PART 6 – Electrical Data ..................................................101
Wiring Diagram ...............................................................102
Electrical Schematic
Electrical Formulas
.......................................................103
.........................................................104
Appendix A – Supplemental Worksheets..........................105
Appendix B – Index of Figures and Tables .......................109
Index of Figures
Index of Tables
.............................................................. 110
................................................................111
Page 3
Page 3
Specifications
Caution: Specifications are for reference only, for actual installations always use the most recent version available online.
These specifications are subject to change without notice.
GENERATOR
Rated Voltage 240
Rated Maximum Load Current (Amps) at 240 Volts (LP)* 29.2
Main Circuit Breaker 30 Amp
Transfer Switch Load Center Circuits** 30A, 240V 1
30A, 240V 1
20A, 120V 3
15A, 120V 3
Phase 1
Number of Rotor Poles 2
Rated AC Frequency 60 Hz
Battery Requirement Group 26R, 12 Volts and 525 CCA Minimum
Weight (unit only in lbs.) 225
Enclosure Composite
Normal Operating Range: This unit is tested in accordance to UL 2200 standards with an operating temperature of -20 °F (-29 °C) to 122 °F. (50 °C). For areas
where temperatures fall below 32 °F (0 °C), a cold weather kit is highly recommended. When operated above 77º F (25º C) there may be a decrease in engine
power. (Please reference the engine specifications section).
These generators are rated in accordance with UL2200, Safety Standard for Stationary Engine Generator Assemblies; and CSA-C22.2 No. 100-04 Standard for
Motors and Generators.
* Natural Gas ratings will depend on specific fuel Btu content. Typical derates are between 10-20% off the LP gas rating.
** Circuits to be moved must be protected by same size breaker. For example, a 15 amp circuit in the main panel must be a 15 amp circuit in the transfer switch.
ENGINE
Type of Engine OHV-432
Number of Cylinders 1
Rated Horsepower @ 3,600 rpm* 14.8
Displacement 432cc
Cylinder Block Aluminum w/Cast Iron Sleeve
Valve Arrangement Overhead Valves
Ignition System Solid-state w/Magneto
Recommended Spark Plug RC12YC
Spark Plug Gap 0.76 mm (0.030 inch)
Compression Ratio 8.2:1
Starter 12 VDC
Oil Capacity Including Filter Approx. 1.1 Qts (1.0L)
Recommended Oil Filter Part # 0H9039
Recommended Air Filter Part # 0H6104
Operating RPM 3,600
* Engine power is subject to and limited by such factors as fuel Btu content, ambient temperature and altitude. Engine power decreases about 3.5 percent for each
1,000 feet above sea level; and also will decrease about 1 percent for each 6 C (10 F) above 16 C (60 F) ambient temperature.
Page 4
Specifications
FUEL CONSUMPTION
Unit
6/7 kW 66 119 0.82/30 1.47/53
* Natural gas is in cubic f eet per hour . **LP is in gallons per hour/cubic feet per hour. Values given are approximate.
1/2 Load Full Load 1/2 Load Full Load
Natural Gas* LP Vapor**
MAJOR FEATURES
Air Filter
Exhaust
Enclosure
Oil Filter
Data Label
(see sample)
Control Panel
Circuit Breaker
Battery
Fuel Inlet
Base
Ground Lug
Fuel Regulator
Page 5
Specifications
Page 6
Specifications
Page 7
NOTES
Page 8
PART 1
GENERAL INFORMATION
PART 1 – GENERAL INFORMATION ......................................9
Section 1.1 – Generator Basics
Introduction
Parts .................................................................... 10
Generator Identification ......................................... 10
Section 1.2 – Measuring Electricity
Meters
The VOM .............................................................. 11
Measuring AC Voltage ...........................................11
Measuring DC Voltage ...........................................11
Measuring AC Frequency ...................................... 11
Measuring Current ................................................ 12
Measuring Resistance ........................................... 12
Electrical Units ...................................................... 13
Ohm’s Law ........................................................... 13
Section 1.3 – Preparation Before Use ................................ 14
Introduction .......................................................... 14
Fuel Consumption ................................................. 14
Reconfigure the fuel system .................................. 14
Section 1.4 – Operating Instructions ................................. 16
Control Panel ........................................................ 16
User Interface ....................................................... 16
Automatic Operation ............................................. 16
Manual Operation.................................................. 16
.......................................................... 10
.................................................................. 11
......................................... 10
...................................11
Section 1.5 – Automatic Operating Parameters .................. 18
Introduction
Utility Failure
Cranking ............................................................... 18
Cranking conditions .............................................. 18
Load Transfer Parameters
Section 1.6 – General Maintenance
Introduction .......................................................... 20
Engine Oil ............................................................. 20
Engine Oil Recommendations ................................ 20
Air Filter ................................................................ 20
Spark Plugs .......................................................... 20
Visual Inspection .................................................. 20
Corrosion Protection ............................................. 20
Valve Clearance .................................................... 20
Battery ................................................................. 21
Section 1.7 – General Troubleshooting .............................. 22
Introduction .......................................................... 22
Recommended Tools ............................................ 22
Troubleshooting Reminders and Tips ..................... 22
Connectors ........................................................... 22
.......................................................... 18
......................................................... 18
..................................... 18
................................... 20
Page 9
Section 1.1
Generator Basics
PART 1
GENERAL INFORMATION
INTRODUCTION
This diagnostic repair manual has been prepared especially for
familiarizing service personnel with the testing, troubleshooting
and repair of the vertical home standby systems. Every
effort has been expended to ensure that the information and
instructions in the manual are both accurate and current.
However, the manufacture reserves the right to change, alter
or otherwise improve the product at any time without prior
notification.
The manual has been divided into several PARTS. Each PART
has been divided into SUBSECTIONS and each subsection
consists of several sub headings.
It is not the manufacturer's intent to provide detailed disassembly
and reassembly of the vertical home standby. It is the
manufacturer's intent to (a) provide the service technician
with an understanding of how the various assemblies and
systems work, (b) assist the technician in finding the cause
of malfunctions, and (c) effect the expeditious repair of the
equipment.
PARTS
Part 1 – Provides the basic understanding of the generator as
well as operating instructions for commons tasks.
Part 2 – Provides the basics of the AC alternator design and the
AC troubleshooting portion of the manual.
Part 3 – Provides the troubleshooting and diagnostic testing
procedure for the 50 amp transfer switch with the EZ Transfer
Operator.
Part 4 – Provides the troubleshooting and diagnostic procedure
for the engine related problems and the controller.
Part 5 – Provides detailed step-by-step instructions for the
replacement of the rotor/stator and engine.
Part 6 – Illustrates all of the electrical and wiring diagrams for
the generator and transfer switch.
GENERATOR IDENTIFICATION
Data Plate
The data plate that is affixed to the generator contains
important information pertaining to the unit, including its model
number, serial number, amperage rating, and voltage rating.
The information from this data plate may be required when
requesting information, ordering parts from the factory.
Item Number
Many home standby generators manufactured are to the unique
specifications of the buyer. The model number identifies the
specific generator set and its unique design specifications.
Serial Number
Used for warranty tracking purposes.
Figure 1. Typical Data Plate
Page 10
GENERAL INFORMATION
GENERAL INFORMATION
PART 1
PART 1
Section 1.2
Section 1.2
Installation Basics
Measuring Electricity
METERS
Devices used to measure electrical properties are called
meters. Meters are available that allow one to measure (a) AC
voltage, (b) DC voltage, (c) AC frequency, and (d) resistance In
ohms. The following apply:
•To measure AC voltage, use an AC voltmeter.
•To measure DC voltage, use a DC voltmeter.
•Use a frequency meter to measure AC frequency In “Her tz”
or “cycles per second”.
•Use an ohmmeter to read circuit resistance, in “ohms”.
THE VOM
A meter that will permit both voltage and resistance to be read
is the “Volt-Ohm-Milliammeter” or “VOM”.
Some VOMs are of the “analog” type (not shown). These
meters display the value being measured by physically
deflecting a needle across a graduated scale. The scale used
must be Interpreted by the user.
“Digital” VOM’s (Figure 2) are also available and are generally
very accurate. Digital meters display the measured values
directly by converting the values to numbers.
Note: Standard AC voltmeters react to the AVERAGE value
of alternating current. When working with AC, the effective
value is used. For that reason a different scale is used on
an AC voltmeter. The scale is marked with the effective or
“rms” value even though the meter actually reacts to the
average value. That is why the AC voltmeter will give an
Incorrect reading if used to measure direct current (DC).
MEASURING AC V OL T A GE
An accurate AC voltmeter or a VOM may be used to read the
generator’s AC output voltage. The following guidelines apply:
1. Always read the generator’s AC output voltage at the
unit’s rated operating speed and AC frequency.
2. The generator’s rated AC output voltage is 250 to 254
VAC and is not adjustable.
3. Only an AC voltmeter may be used to measure AC
voltage. DO NOT USE A DC VOLTMETER FOR THIS
PURPOSE.
Generators produce high and dangerous voltages.
Contact with high voltage terminals will result in
dangerous and possibly lethal electrical shock.
MEASURING DC VOL T A GE
A DC voltmeter or a VOM may be used to measure DC voltages.
Always observe the following rules:
1. Always observe correct DC polarity.
a. Some VOM’s may be equipped with a polarity switch.
b. On meters that do not have a polarity switch, DC
polarity must be reversed by reversing the test leads.
2. Before reading a DC voltage, always set the meter to a
higher voltage scale than the anticipated reading. If in
doubt, start at the highest scale and adjust the scale
downward until correct readings are obtained.
Figure 2. Digital VOM
3. The design of some meters is based on the “current flow”
theory while others are based on the “electron flow”
theory.
a. The “current flow” theory assumes that direct current
flows from the positive (+) to the negative (-).
b. The “electron flow” theory assumes that current flows
from negative (-) to positive (+).
Note: When testing generators, the “current flow” theory is
applied. That is, current is assumed to flow from positive
(+) to negative (-).
MEASURING AC FREQUENCY
The generator’s AC output frequency is proportional to Rotor
speed. Generators equipped with a 2-pole Rotor must operate
at 3600 rpm to supply a frequency of 60 Hertz. Units with
4-pole Rotors must run at 1800 rpm to deliver a 60 Hertz
output.
Page 11
Section 1.2
Measuring Electricity
PART 1
GENERAL INFORMATION
MEASURING CURRENT
Clamp-On
To read the current flow, in AMPERES, a clamp-on ammeter
may be used. This type of meter indicates current flow
through a conductor by measuring the strength of the magnetic
field around that conductor. The meter consists essentially
of a current transformer with a split core and a rectifier type
instrument connected to the secondary. The primary of the
current transformer is the conductor through which the current
to be measured flows. The split core allows the Instrument
to be clamped around the conductor without disconnecting it.
Current flowing through a conductor may be measured safely
and easily. A line-splitter can be used to measure current in a
cord without separating the conductors.
In-Line
Alternatively, to read the current flow in AMPERES, an in-line
ammeter may be used. Most Digital Volt Ohm Meters (VOM)
will have the capability to measure amperes.
This usually requires the positive meter test lead to be connected
to the correct amperes plug, and the meter to be set to the
amperes position. Once the meter is properly set up to measure
amperes the circuit being measured must be physically broken.
The meter will be in-line or in series with the component being
measured.
In Figure 5 the control wire to a relay has been removed. The
meter is used to connect and supply voltage to the relay to
energize it and measure the amperes going to it.
1.00 A
BATTERY
+-
RELAY
Figure 3. Clamp-On Ammeter
Figure 4. A Line-Splitter
Note: If the physical size of the conductor or ammeter
capacity does not permit all lines to be measured simultaneously, measure current flow in each individual line.
Then, add the individual readings.
Figure 5. A VOM as an In-line Amp Meter
MEASURING RESISTANCE
The Volt-Ohm-Milliammeter may be used to measure the
resistance in a circuit. Resistance values can be very valuable
when testing coils or windings, such as the Stator and Rotor
windings, or checking a wire for an open or grounded condition.
When testing Stator windings, keep in mind that the resistance
of these windings is very low. Some meters are not capable of
reading such a low resistance and will simply read CONTINUITY.
If proper procedures are used, the following conditions can be
detected using a VOM:
•A “shor t-to-ground” condition in any Stator or Rotor
winding, or a short to ground on a specific control wire.
•Shorting together of any two parallel Stator windings.
•Shorting together of any two isolated Stator windings.
•An open condition in any Stator or Rotor winding, or an open
in a control wire.
Page 12
GENERAL INFORMATION
PART 1
Section 1.2
Measuring Electricity
Component testing may require a specific resistance value
or a test for INFINITY or CONTINUITY. Infinity is an OPEN
condition between two electrical points, which would read as
no resistance, or OL (Open Line) on a VOM. Continuity is a
closed condition between two electrical points, which would
be indicated as very low resistance (000.000) or “ZERO” on
a VOM.
ELECTRICAL UNITS
Ampere
The rate of electron flow in a circuit is represented by the
AMPERE. The ampere is the number of electrons flowing past
a given point at a given time. One AMPERE is equal to just
slightly more than 6.241x10
With alternating current (AC), the electrons flow first in one
direction, then reverse and move in the opposite direction.
They will repeat this cycle at regular intervals. A wave diagram,
called a “sine wave” shows that current goes from zero to
maximum positive value, then reverses and goes from zero
to maximum negative value. Two reversals of current flow
is called a cycle. The number of cycles per second is called
frequency and is usually stated in “Hertz”.
Volt
The VOLT is the unit used to measure electrical PRESSURE,
or the difference in electrical potential that causes electrons to
flow. Very few electrons will flow when voltage is weak. More
electrons will flow as voltage becomes stronger. VOLTAGE
may be considered to be a state of unbalance and current flow
as an attempt to regain balance. One volt is the amount of
Electromotive Force (EMF) that will cause a current of 1 ampere
to flow through 1 ohm of resistance.
18
electrons per second.
Ohm
The OHM is the unit of RESISTANCE. In every circuit there
is a natural resistance or opposition to the flow of electrons.
When an EMF is applied to a complete circuit, the electrons
are forced to flow in a single direction rather than their free or
orbiting pattern. The resistance of a conductor depends on
(a) its physical makeup, (b) its cross-sectional area, (c) its
length, and (d) its temperature. As the conductor’s temperature
increases, its resistance increases in direct proportion. One (1)
ohm of resistance will permit one (1) ampere of current to flow
when one (1) volt of EMF is applied.
OHM’S LAW
A definite and exact relationship exists between VOLTS, OHMS
and AMPERES. The value of one can be calculated when the
value of the other two are known. Ohm’s Law states that in
any circuit the current will increase when voltage increases but
resistance remains the same, and current will decrease when
resistance increases and voltage remains the same.
VOLTS
(E)
AMPS
(I)
OHMS
(R)
-
Conductor of a
Circuit
OHM - Unit measuring resistance
or opposition to flow
AMPERE - Unit measuring rate of
current flow (number of electrons
past a given point)
VOLT - Unit measuring force or
difference in potential
causing current flow
Figure 6. Electrical Units
+
Figure 7. Ohm’s Law
If AMPERES is unknown while VOLTS and OHMS are known,
use the following formula:
OHMS
If VOLTS is unknown while AMPERES and OHMS are known,
use the following formula:
If OHMS is unknown but VOLTS and AMPERES are known, use
the following:
AMPERES
AMPERES =
VOLTS = AMPERES x OHMS
OHMS
VOLTS
VOLTS
=
Page 13
Section 1.3
Preparation Before Use
PART 1
GENERAL INFORMATION
INTRODUCTION
It is the responsibility of the installer to ensure that the Generator
installation was performed properly. A careful inspection
must be performed when the installation is complete. All
applicable codes, standards, and regulations pertaining to
such installations must be strictly complied with. In addition,
regulations established by the Occupational Safety and Health
Administration (OSHA) must be complied with as well.
Prior to initial startup of the unit, the installer must ensure that
the Generator has been properly prepared for use. This includes
the following:
•An adequate supply of the correct fuel must be available for
Generator operation.
•The engine must be properly serviced with the
recommended oil.
•With liquid propane (LP), use only the “vapor withdrawal”
system. This type of system uses the vapors formed above
the liquid fuel in the storage tank.
The engine has been fitted with a fuel carburetion system that
meets the specification of the 1997 California Air Resources
Board for tamper-proof dual fuel systems. The unit will run
on natural gas or LP, but it has been factory set and tested to
run on natural gas. When the change from natural gas to LP is
needed, the fuel system needs to be re-configured.
Recommended fuels should have a British Thermal Unit (BTU)
content of at least 1,000 BTU’s per cubic feet for natural gas; or
at least 2,520 BTU’s per cubic feet for LP. Ask the fuel supplier
for the BTU content of the fuel.
Recommended fuel pressures for natural gas and liquid
propane vapor (LPV) are as follows:
Note: All pipe sizing, construction and layout must comply
with NFPA 54 for natural gas applications and NFPA 58 for
liquid propane applications. After installation, verify that the
fuel pressure NEVER drops below five (5) inches water column for natural gas or ten (10) inches water column for LPV.
Prior to installation of the Generator, the installer should consult
local fuel suppliers or the fire marshal to check codes and
regulations for proper installation. Local codes will mandate
correct routing of gaseous fuel line piping around gardens,
shrubs and other landscaping to prevent any damage.
Special considerations should be given when installing the unit
where local conditions include flooding, tornados, hurricanes,
earthquakes and unstable ground for the flexibility and strength
of piping and their connections.
Use an approved pipe sealant or joint compound on all threaded
fittings.
Verify that gas meter is capable of providing enough fuel flow
to include household appliances.
Btu Flow Requirements - Natural Gas
BTU flow required for each unit based on 1000 BTU per cubic
foot.
•6kW — 119,000 BTU/Hour (Natural Gas)
RECONFIGURE THE FUEL SYSTEM
Procedure
1. Remove the generator enclosure roof by turning the four
quarter turn latches on the roof top. Push down slightly
on the latch then turn 90 degrees to release. The latch
should pop up as shown.
Figure 8.
2. Remove the two side panels of the enclosure by lifting the
panels straight up until they are clear.
FUEL CONSUMPTION
Unit
6/7 kW 66 119 0.82/30 1.47/53
* Natural gas is in cubic f eet per hour .
**LP is in gallons per hour/cubic feet per hour.
Values given are approximate.
Page 14
Natural Gas* LP Vapor**
1/2 Load Full Load 1/2 Load Full Load
Figure 9.
3. Carefully place the roof and side panels to one side.
4. Locate the fuel throttle assembly mounted to the engine
intake.
GENERAL INFORMATION
PART 1
Figure 10.
5. To change the fuel selection, remove the hose clamp and
hose from the throttle assembly.
6. Remove the Natural Gas (Larger ID) fuel jet from the fuel
inlet.
Section 1.3
Preparation Before Use
9. Insert the Propane fuel jet into the end of the fuel inlet.
10. Reinstall the hose and clamp onto the fuel inlet and
secure.
11. Verify the hose has not been kinked in any way.
Fuel Inlet
O-Ring (installed)
Throttle
Assembly
Fuel Jet
Regulator
Hose
Hose Clamp
7. Obtain the fuel jet for Propane (Smaller ID that has been
supplied loose with the owners manual).
8. Verify that the O-ring, supplied loose with the owners
manual is installed, into the groove of the fuel jet.
Figure 11.
12. The generator is now ready to run on LP Vapor fuel.
Page 15
Section 1.4
Operating Instructions
PART 1
GENERAL INFORMATION
CONTROL PANEL
WARNING! With the switch set to AUTO, the engine
may crank and start at any time without warning. Such
automatic starting occurs when Utility power source
voltage drops below a preset level or during the normal
exercise cycle. To prevent possible injury that might be
caused by such sudden starts, always set the switch to
the OFF position and remove the fuse before working on
or around the Generator or transfer switch. Then, place
a “DO NOT OPERATE” tag on the Generator panel and
on the transfer switch.
AUTO-OFF-MANUAL
AUTO – Selecting this switch activates fully automatic system
operation. It also allows the unit to automatically start and
exercise the engine every seven days at the time chosen by
the user.
OFF – This switch position shuts down the engine. This
position also prevents automatic operation.
MANUAL – Setting the switch to the MANUAL position will
crank and start the engine. Transfer to standby power will not
occur unless there is a failure of Utility.
7.5 Amp Fuse
This fuse protects the controller as wells as the DC components
against overload. If the fuse element has melted open due to an
overload, engine cranking and or running will not be possible.
Should a fuse replacement become necessary, use only an
identical 7.5 amp replacement fuse.
USER INTERFACE
The generator is equipped with an internal exercise timer. Once
set, the Generator will start and exercise every seven days, on
the day of the week and the time of day specified. During this
exercise period, the unit runs for approximately 12 minutes and
then shuts down. Transfer of loads to the Generator output
does not occur during the exercise cycle unless Utility is lost.
Refer to “Setting the exercise time” in Section 1.4.
Note: The exercise will only work with the AUTO-OFFMANUAL switch in the AUTO position.
To select automatic operation
The following procedure applies only to those installations
which utilize an air-cooled generator in conjunction with a
transfer switch. Residential transfer switches do not have
intelligent circuits of their own. Printed circuit board logic in
the controller controls the automatic operation of the transfer
switch and the generator.
To select automatic operation when a transfer switch is installed
along with a home standby generator, the procedure is as
follows.
1. Ensure that the transfer mechanism in the transfer switch
is in the “Utility” position. If needed, turn OFF or OPEN
the Utility source Main Line Circuit Breaker and manually
transfer the breaker to the “Utility” position.
2. CLOSE or turn ON the Utility source Main Line Circuit
Breaker and ensure Utility voltage is available to the
UTILITY terminals N1 and N2.
3. Actuate the Generator main line circuit breaker (MLCB) to
its “Closed” position.
4. Set the Generators AUTO-OFF-MANUAL switch to the
AUTO position.
Following the procedure of Steps 1 through 4, a dropout of
Utility voltage below a preset level will result in automatic
Generator cranking and start-up. Following startup, the transfer
switch will actuate to the “Standby” position.
MANUAL OPERATION
Transfer to “Standby” and Manual Startup
To transfer electrical loads to the Generator and to start the
generator manually, the procedure is as follows:
1. On the generator, set the AUTO-OFF-MANUAL switch to
the OFF position.
2. On the generator, set the main line circuit breaker (MLCB)
to the “Open” position.
3. Locate a means of Utility disconnect and set it to the OFF
position.
4. Manually actuate the breaker to the “Standby” position in
the transfer switch.
AUTOMATIC OPERATION
CAUTION! The Generators Voltage and Frequency must
be verified with the Generator Main Line Circuit Breaker
(MLCB) OFF or OPEN Prior to selecting Automatic or
Manual operation!
Page 16
5. On the generator, set the AUTO-OFF-MANUAL switch to
the MANUAL position.
WARNING! Engine will crank and start!
6. Let the engine warm up and stabilize for a minute or two
at no-load. Set the generators MLCB to the “Closed”
position. Generator voltage should now be available to
the transferred electrical loads.
GENERAL INFORMATION
Retransfer Back to “Utility” and Manual Shutdown
To shutdown the generator and retransfer electrical loads back
to the “Utility” position, the procedure is as follows:
1. Set the generators MLCB to its OPEN position.
2. Allow the generator to run at no-load for several minutes
to cool down.
3. Set the generators AUTO-OFF-MANUAL switch to the OFF
position.
4. Locate a means of Utility disconnect and set it to the OFF
position.
5. Manually actuate the breaker in the transfer switch to the
“Utility” position.
6. Restore Utility voltage to the transfer switch, by the means
that was utilized in Step 4.
7. Set the generator’s AUTO-OFF-MANUAL switch to the
AUTO position.
With the generator in AUTO, a dropout in Utility voltage below
a preset level will result in automatic generator cranking and
start-up. Following startup, the transfer switch will actuate to
the “Standby” position.
PART 1
Section 1.4
Operating Instructions
Page 17
Section 1.5
Automatic Operating Parameters
PART 1
GENERAL INFORMATION
INTRODUCTION
When the generator is installed in conjunction with a transfer
switch, either manual or automatic operation is possible.
UTILITY FAILURE
Initial Conditions
The generator is in AUTO, ready to run, and the transfer switch
is running on Utility. When Utility fails (below 65% of nominal),
a 10 second line interrupt delay time is star ted. If the Utility is
still not present when the timer expires, the engine will crank
and start. Once started a five (5) second engine warm-up timer
will start.
When the warm-up timer expires the controller will transfer load
to the generator. If Utility voltage is restored (above 75% of
nominal) at any time between the initiation of the engine start
and when the generator is ready to accept load, (five second
warm-up time has not elapsed), the controller will complete the
start cycle and run the generator through its normal cool down
cycle; however the switch will remain in the “Utility” position.
CRANKING
The controller will cyclic crank the engine 5 times as follows:
16 second crank, 7 second rest, 16 second crank, 7 second
rest, followed by 3 additional cycles of 7 second crank followed
by 7 second rests.
Failure To Start
Failure to start is defined as any of the following occurrences
during cranking.
1. Not reaching starter dropout within the specified crank
cycle.
Note: Starter dropout is defined as 4 cycles at 1,000 RPM
2. Reaching starter dropout, but not reaching 2200 rpm
within 15 seconds. After which the controller will go into
a rest cycle of 7 seconds, the continue the rest of the
crank cycle.
Note: During a rest cycle the start and fuel outputs are deenergized and the magneto output is shorted to ground.
5. Once the controller sees an RPM signal it will energize the
fuel solenoid and continue the crank sequence. The fuel
solenoid does not activate earlier because if the engine
does not crank, this would potentially fill the engine/
exhaust up with unspent fuel. It takes at least 3 seconds
to detect cranking on the engine with a magneto RPM
measurement. This would result in 3 seconds of fuel
being delivered, increasing the chances of a backfire.
6. The starter motor will disengage when speed reaches
starter dropout.
7. If the generator does not reach 2200 rpm within 15
seconds, re-crank cycle will occur.
8. If the engine stops turning between starter dropout and
2200 RPM the controller will go into a rest cycle of 7
seconds and re-crank ( if additional crank cycles exist.)
9. Once started the generator will wait for a hold off
period before starting to monitor oil pressure and oil
temperature. Refer to Section 4.2 “Engine Protective
Devices”
10. During a MANUAL crank attempt, if the AUTO-OFFMANUAL switch is set from MANUAL to OFF, the crank
attempt will abort.
11. During automatic crank attempt, if the Utility returns, the
crank cycle does NOT abort, but continues until complete.
Once the engine starts, it will run for one minute then
shutdown.
LOAD TRANSFER PARAMETERS
The transfer of load when the generator is running is dependent
upon the operating mode as follows:
Manual
•No transfer to Standby when Utility is present
•Transfer to Standby will occur if Utility fails (below 65% of
nominal) for 10 consecutive seconds.
•Transfer back to Utility when Utility returns for 15 consecu-
tive seconds. The engine will continue to run until removed
from the Manual mode.
CRANKING CONDITIONS
The following notes apply during the crank cycle
1. Starter motor will not engage within 5 seconds of the
engine shutting down.
2. The fuel output will not be energized with the starter
3. The starter and magneto outputs will be energized
together.
4. Once the star ter energizes, the controller will begin
looking for engine rotation. If it does not see an RPM
signal within 3 seconds it will shut down and latch out on
“RPM Sensor loss”
Page 18
Auto
•Transfer to standby will occur if Utility fails below (65% of
nominal) for 10 consecutive seconds.
•A five second engine warm-up timer will initialize
•Transfer back to the “Utility” position if Utility subsequently
returns
•Transfer to the “Standby” position if Utility is still not present.
•Transfer back to Utility once Utility returns (above 75% of
nominal) for 15 seconds.
•Transfer back to Utility, if present, if the generator is shutdown for any reason ( such as the switch turned to the OFF
position or a shutdown alarm.
GENERAL INFORMATION
Exercise
•Exercise will not function if the generator is already running
in either AUTO or MANUAL mode.
•During exercise, the controller will only transfer if Utility fails
during exercise for 10 seconds, and will follow the steps
outline above for AUTO operation.
Utility Restored
The generator is running, switch is in the “Standby” position,
running in Utility failure. When the Utility returns (above 75%
of nominal), a 15 second return to Utility timer will start. At
the completion of this timer, if the Utility supply is still present
and acceptable, the controller will transfer the load back to
the Utility and run the engine through a one minute cool down
period and then shutdown. If Utility fails for three seconds
during this cool down period, the controller will transfer load
back to the generator and continue to run while monitoring for
Utility to return.
PART 1
Section 1.5
Automatic Operating Parameters
Page 19
Section 1.6
General Maintenance
PART 1
GENERAL INFORMATION
INTRODUCTION
Performing proper maintenance on a Generator will ensure
proper function during a Utility failure. Once a Generator has
failed, it is already too late. Ensuring the proper oil changes and
inspections have been completed at the specified times will
help keep the Generator reliable.
ENGINE OIL
Modern oils play vital functions in protecting the engine.
Lubricating oil acts to reduce friction and wear, cool engine
parts, seal combustion chambers, clean engine components,
and inhibit corrosion. See Table 1 “Service Schedule” for
specific inspection items and interval
ENGINE OIL RECOMMENDATIONS
All oil should meet minimum American Petroleum Institute (API)
Service Class SJ, SL or better. Do not use special additives.
Select the oil’s viscosity grade according to the expected
operating temperature.
SAE 30 Above 32º F
10W-30 Between 40ºF and -10ºF
Synthetic 5W-30 10ºF and below
VISUAL INSPECTION
During all service intervals, a proper visual inspection must be
conducted to ensure proper function, airflow, and to prevent
fire hazards.
Air inlet and outlet openings in the Generator compartment
must be open and unobstructed for continued proper operation.
This includes such obstructions as high grass, weeds, brush,
leaves, and snow.
AIR INTAKE
AIR OUTLET
AIR OUTLET
AIR FILTER
Air is necessary for successful combustion in the engine. Clean
air (almost 100% pure) is critical to engine survival and vital to
its performance. There are operational signs when an air filter
has become completely plugged. The engine begins to lose
power, and fuel consumption increases. Black smoke may blow
from the exhaust. Continued operation with a plugged air filter
may cause severe damage to the engine.
SPARK PLUGS
Good spark is essential to properly maintaining the engine.
Although replacement may not be required, inspection of the
plugs during routine maintenance is critical. Always verify
that spark plugs are gapped according to the specifications.
Improperly gaped spark plugs will effect the operation of the
engine.
See Test 65 for diagnosing spark plug related problems.
See “Specifications” for specific spark plug gaps.
AIR INTAKE
Figure 12. Cooling Vent Locations
CORROSION PROTECTION
Spray engine linkages with a light oil such as WD-40.
CAUTION! Do not spray flammable oils on a hot or
running engine.
VALVE CLEARANCE
Proper valve clearance is vital to ensuring longevity of the
engine. After the first 6 months of operation, check the engine
valve clearance and adjust as necessary. Checking of the
engine valve clearance thereafter periodically will increase
reliability of the Generator. Refer to Test 70 for Specification and
adjustment procedure.
Some symptoms of an engine with valves in need of adjustment
are:
•Hard star ting
•Smoke out of the exhaust
•Rough running
•Lack of horse power
Page 20
GENERAL INFORMATION
PART 1
General Maintenance
Section 1.6
BATTERY
Performing proper battery maintenance at the required intervals
will allow for proper starting of the Generator during a power
outage. Some common things to look for and check during
maintenance are:
•Inspect the battery posts and cables for tightness and
corrosion. Tighten and clean as necessary.
•Check the battery fluid level of unsealed batteries and, if necessary, fill with Distilled Water only. Do not use tap water in
batteries.
•Have the state of charge and conditions checked. This should
be done with an automotive-type battery hydrometer.
Note: See Test 56 for further testing the state of a battery.
Table 1. Service Schedule
SYSTEM/COMPONENT PROCEDURE FREQUENCY
X = Action
R = Replace as Necessary
Inspect Change Clean
* = Notify Dealer if Repair is
Needed.
FUEL
Fuel lines and connections*
X M
LUBRICATION
Oil level
Oil
Oil filter
X M or 24 hours of
X 1Y or 100 hours
X 1Y or 100 hours
COOLING
Enclosure louvers
X X W
BATTERY
Remove corrosion, ensure
dryness
Clean and tighten battery
terminals
Check charge state
Electrolyte level
X X M
X X M
X R EVERY 6 M
X R EVERY 6 M
ENGINE AND MOUNTING
Air cleaner
Spark plug
X R 1Y or 200 hours
X R 1Y or 200 hours
GENERAL CONDITION
Vibration, Noise, Leakage, Temperature*
X M
COMPLETE TUNE-UP* TO BE COMPLETED BY A DEALER 1Y or 200 hours
* Contact the nearest dealer for assistance if necessary.
** Change oil and filter after first eight (8) hours of operation and then every 100 hours thereafter, or 1 year, whichever occurs first.
Change sooner when operating under a heavy load or in a dusty or dirty environment or in high ambient temperatures.
W = Weekly
M = Monthly
Y = Yearly
continuous operation.
of operation.**
of operation.**
Page 21
Section 1.7
General Troubleshooting
PART 1
GENERAL INFORMATION
INTRODUCTION
This section familiarizes the service technician with the
manufacturer recommended procedures for the testing and
evaluation of various problems that can occur on the standby
generators. It is highly recommended that you read these
introductory tips before you attempt to troubleshoot any of the
three main generator components: AC Generator, Engine, or
the Transfer Switch. The Troubleshooting Flow Charts provide
the simplest, quickest, systematic means to troubleshoot the
typical problems that might occur during the lifetime of the unit.
If you use the flow charts and perform the indicated tests, you
will be able to identify the faulty component, which can then be
repaired or replaced as necessary.
The test procedures in each section do require a basic
knowledge of electricity and electrical safety, hand tool skills,
and use of Volt-Ohm-Meters.
RECOMMENDED TOOLS
In addition to the normal hand tools required, some test
procedures may require the use of specialized test equipment.
At a minimum you must have a meter that measures AC
voltage and frequency, and DC voltage and current (digital
multi meters (DMM) are recommended); standard meter test
leads, a set of piercing probe leads , and a set of pin probe
leads for the connector pins. The manufacturer carries a set
of acceptable piercing probes (PN 0G7172), or other suppliers
piercing probes may be used. Fluke provides a high quality
piercing probe, PN AC89, which is highly recommended. The
manufacturer also carries a set of flexible pin leads for use with
the connector plugs (PN 0J09460SRV).
Recommended Tools Check List
p General Mechanics Tool Box
p A Meter Capable of Measuring Frequency (Hz), AC & DC
volts, DC amps, and Ohms
p A Clamp-on Ammeter
A 1/4” & 3/8” Metric & SAE Socket Set
p
p Allen Wrenches (Metric & SAE)
p Manometer
p Spark Tester
p Compression Gauge
p Oil Pressure Gauge
p Leak Down Tester
TROUBLESHOOTING REMINDERS AND TIPS
The most important step in troubleshooting is identifying the
actual problem.
The next step is to determine the applicable flow chart to use
to help diagnose the problem. Use the flow chart index for the
part of the generator you are working with. If it is problem with
voltage, use Part 2 – AC Generators; for engine problems use
Part 4 – Engine/DC Control; for a problem with the transfer
switch, use Part 3 – Transfer Switch. The index for each will
help you clarify the problem and the flow chart to use. In each
flow chart start at the top and use the test indicated to verify
whether a component or control item is working properly or not.
At the end of each test follow the “good” or “bad” arrows and
perform the next test.
It is always good practice to continue to ask questions during
the troubleshooting process. When evaluating a problem, these
questions may help identify the problem quicker.
•What is it doing? (low voltage; not cranking; not transferring;
etc)
•What should it do? (run and start; transfer; shutdown; etc)
•Does the same thing happen each time?
•When is it happening?
•What could or would cause this?
•What type of test will either prove or disprove the cause of
the fault?
Figure 13. Test Probes
For engine troubleshooting you will need a good manometer
which measures low pressure in Inches of Water Column (IN
WC or IN H20). An ignition spark tester is also a handy tool to
have when working with air-cooled engines.
Testing and troubleshooting methods covered in each section
are not exhaustive. No attempt has been made to discuss,
evaluate and advise the home standby service trade of all
conceivable ways in which service and trouble diagnosis must
be performed. Accordingly, anyone who uses a test method
not recommended herein must first satisfy himself that the
procedure or method he has selected will jeopardize neither
his nor the products safety, and will not cause damage to any
connectors or components.
Page 22
CONNECTORS
A number of the tests require the use of a volt-meter and a set
of wire piercing probes. When using the piercing probes make
sure you use some liquid tape or silicon to coat the insulation
where you pierced it; this will keep moisture out and prevent
long term corrosion.
It is very easy to damage the female pins in the connectors
on the control panel and the C1 connector (Molex connector)
which goes to the alternator can.
DO NOT ATTEMPT TO PUSH PROBE TIPS INTO THE FEMALE
PINS OF THE MOLEX CONNECTORS; doing so will damage the
female pin which will create another problem. Use the piercing
probes on the correct wire to check for the appropriate voltages
; or use the flexible pin leads, available from the manufacturer
(PN 0J09460SRV) to work with the connector plugs.
PART 2
AC GENERATORS
PART 2 – AC Generators ....................................................23
Section 2.1 – Description and Components
Introduction
Engine-Generator Drive System ............................. 24
Alternator Assembly ............................................. 24
Brush Holder and Brushes
Other AC Generator Components
Section 2.2 – Operational Analysis .................................... 26
Startup ................................................................. 26
On-Speed Operation .............................................. 26
Field Excitation ...................................................... 26
AC Power Winding Output ..................................... 26
Section 2.3 – Troubleshooting Flowcharts ......................... 27
Introduction .......................................................... 27
Problem 1 – Generator Produces Zero Voltage
or Residual Voltage ............................................... 27
Problem 2 – Generator Produces
Low Voltage at No-Load ........................................28
Problem 3 – Generator Produces
High Voltage at No-Load .......................................29
Problem 4 - Voltage and Frequency
Drop Excessively When Loads Are Applied ............ 29
.......................................................... 24
.................................... 24
....................... 24
.......................... 25
Section 2.4 – Diagnostic Tests .......................................... 30
Introduction
Safety ................................................................... 30
AC Troubleshooting............................................... 30
Test 1 – Check Main Circuit Breaker ...................... 30
Test 4 – Fixed Excitation /Rotor Amp Draw Test ..... 30
Test 6 – Resistance Check of Rotor Circuit ............ 32
Test 7 – Check Brushes and Slip Rings
Test 9 – Test the Stator ......................................... 33
Test 10 – Test Rotor Assembly .............................. 34
Test 11 – Check AC Output Voltage ....................... 34
Test 12 – Check AC Output Frequency ................... 34
Test 13 – Adjust Engine Governor ......................... 35
Test 14 – Adjust Voltage Regulator ....................... 35
Test 15 – Check for Overload Condition ................. 36
Test 16 – Check Voltage and
Frequency Under Load ........................... 36
.......................................................... 30
................. 32
Page 23
Section 2.1
SLIP RINGS
BEARING
Description and Components
INTRODUCTION
The alternator contained within the generator is a revolving field
(rotor) type with a stationary armature (stator), and excitation
to the field provided through brushes and slip rings (direct
excitation). The generator may be used to supply electrical
power for the operation of the 120 and/or 240 VAC, 1-phase,
60 Hz, AC loads.
ENGINE-GENERATOR DRIVE SYSTEM
The air-cooled engine is directly coupled to the rotor internally.
Both the engine and the rotor operate at 3600 rpm to provide a
60 HZ AC output.
ALTERNATOR ASSEMBLY
The standard alternator consists of three basic components;
a rotor, stator, and brush assembly. The rotor assembly
provides the magnetic field which will induce a voltage into the
stator assembly. The brush assembly provides the electrical
connection to the rotor, which allows for excitation voltage and
current to create the needed magnetic field.
PART 2
STATOR
BA
RED
+
C1
RED(+)
WHT
BLK
IC
IC
AC GENERATORS
WHT
WHT
BLK
BLU
AVR
Rotor
Operating the 2-pole rotor at 3600 rpm will supply 60 HZ AC.
The term “2-pole” means the rotor has a single north and a
single south magnetic pole. Held in place with a single through
bolt, the tapered rotor shaft mounts to the tapered crankshaft
of the engine. As the rotor rotates its lines of magnetic flux cut
across the stator windings and induce a voltage into the stator
windings. The rotor shaft has a positive and negative slip ring,
with the positive slip ring nearest the lower bearing carrier. The
bearing is pressed onto the end of the rotor shaft.
Figure 14. Rotor
Stator
The stator houses a dual power winding and an excitation
winding. Coming from the stator there are eight stator leads as
shown in Figure 15.
An adapter molded into the engine block and a rear-bearing
carrier support the stator can. Four stator bolts connect the
rear bearing carrier and the stator can to the engine.
Figure 15. Stator Leads
BRUSH HOLDER AND BRUSHES
Attached to the lower bearing carrier, the brush holder and
brushes allow for electrical connection to the rotor. Positive
and negative brushes are retained in the brush holder, with the
positive brush riding on the slip ring nearest the rotor bearing.
The Red wire connects to the positive brush and the Black
Wire to the negative brush. The rotor windings receive rectified
and regulated field excitation voltage (DC) through the Red and
Black Wires. The current flow creates a magnetic field around
the rotor having a flux concentration that is proportional to the
amount of current flow on the Red and Black Wires.
RED
+
-
Figure 16. Brush Holder and Brushes
BLACK
Page 24
AC GENERATORS
PART 2
OTHER AC GENERATOR COMPONENTS
Located within the generator control panel enclosure are the
voltage regulator and the main line circuit breaker.
Voltage Regulator
Unregulated AC output from the stator excitation winding is
delivered to the regulator’s DPE circuit through the two Blue
wires and C1-1 and C1-2. The voltage regulator rectifies
that voltage and, based on stator AC power winding sensing,
regulates it. The rectified and regulated field excitation current is
then delivered to the rotor windings from the positive (+) Red
Wire and negative (-) Black Wire (originates as White Wire from
regulator and changes to Black at the C1 connector). Stator AC
power winding “sensing” is delivered to the regulator through
the Green and White Wires.
Main Line Circuit Breaker
The main line circuit breaker protects the generator against
electrical overload. Refer to “Specifications” section for the
specific amperage ratings.
Section 2.1
Description and Components
BLUE BLACK
E1 E2
LOAD SIDE
Figure 17. Main Line Circuit Breaker
LINE
Page 25
Section 2.2
Operational Analysis
PART 2
AC GENERATORS
STARTUP
When the engine is started, permanent magnets embedded in
the rotor induce a voltage into (a) the stator AC power windings,
(b) the stator excitation or DPE windings. In an “on-speed”
(engine cranking) condition, this magnetism is capable of
creating approximately one to three volts AC.
ON-SPEED OPERATION
As the engine accelerates, the voltage that is induced into the
stator windings increases rapidly, due to the increasing speed
at which the rotor operates.
FIELD EXCITATION
An AC voltage is induced into the stator excitation (DPE)
windings. The DPE winding circuit is delivered to the voltage
regulator through the two Blue Wires and C1-1 and C1-2.
Unregulated alternating current flows from the winding to the
regulator. The voltage regulator “senses” AC power winding
output voltage and frequency through the Green and White
Wires.
The regulator changes the AC from the excitation winding to DC
Field Excitation. In addition, based on the AC sensing wires,
it regulates the flow of direct current to the rotor. The rectified
and regulated current flow from the regulator is delivered to the
rotor windings through the (+) Red Wire and the positive brush
and slip ring. This excitation voltage flows through the rotor
windings and through the negative (-) slip ring and brush on
the negative (-) Black Wire.
The greater the current flow through the rotor windings, the
more concentrated the lines of flux around the rotor become.
The more concentrated the lines of flux around the rotor that cut
across the stationary stator windings, the greater the voltage
that is induced into the stator windings.
Initially, the AC power winding voltage sensed by the regulator
is low. The regulator reacts by increasing the flow of field
excitation voltage to the rotor until voltage increases to a
desired level. The regulator then maintains the desired voltage.
For example, if voltage exceeds the desired level, the regulator
will decrease the flow of field excitation voltage. Conversely, if
voltage drops below the desired level, the regulator responds by
increasing the flow of excitation current.
AC POWER WINDING OUTPUT
A regulated voltage is induced into the stator AC power windings.
When electrical loads are connected across the AC power
windings to complete the circuit, current can flow in the circuit.
ENGINE DIRECT
DRIVE
STATOR
POWER
WINDING
TO LOAD
MLB
WINDING
MAGNETIC
FIELD
ROTOR
MAGNETIC
FIELD
MLB = MAIN LINE CIRCUIT BREAKER
SENSING
STATOR
POWER
VOLTAGE
REGULATOR
STATOR
EXCITATION
WINDING
Page 26
Figure 18. Operating Diagram
AC GENERATORS
PART 2
Troubleshooting Flow Charts
Section 2.2
INTRODUCTION
Use the “Flow Charts” in conjunction with the detailed instructions in Section 2.4. Test numbers used in the flow charts correspond
to the numbered tests in Section 2.4. The first step in using the flow charts is to identify the correct problem on the following pages.
For best results, perform all tests in the exact sequence shown in the flow charts.
Problem 1 – Generator Produces Zero Voltage or Residual Voltage
RE-TEST
TEST 1 –
CHECK MAIN
CIRCUIT BREAKER
RESET TO
“ON” OR
REPLACE IF
BAD
REPLACE
VOLTAGE
REGULATOR
ON
GOOD
TEST 4 – PERFORM
FIXED EXCITATION /
ROTOR AMP DRAW
A
B
TEST 9 – TEST
STATOR
C
D
G
TEST 6 –
RESISTANCE
CHECK OF
ROTOR CIRCUIT
BAD
REPAIR
OR REPLACE
FUSES
CHECK
VOM
FUSES
GOOD
PERFORM
INSULATION
RESIST ANCE TEST
REPLACE
STATOR
ONLY
GOOD
BAD
TEST 10 –
TEST ROTOR
ASSEMBLY
BAD
REPLACE
ROTOR AND
STATOR
TEST 7 –
RESIST ANCE TEST
CHECK
BRUSHES &
SLIP RINGS
GOOD
TEST 10 –
TEST ROTOR
ASSEMBLY
GOOD
PERFORM
INSULATION
BAD
REPLACE
ROTOR ONLY
GOOD
TEST 9 – TEST
STATOR
BAD
REPLACE
ROTOR AND
STATOR
Page 27
Section 2.3
Troubleshooting Flow Charts
PART 2
AC GENERATORS
Problem 1 – Generator Produces Zero Voltage or Residual Voltage (Continued)
TEST 4 – PERFORM
FIXED EXCITATION /
ROTOR AMP DRAW
TEST 10 –
TEST ROTOR
ASSEMBLY
BAD
E
H
TEST 9 – TEST
STATOR
GOOD
REPLACE
ROTOR ONLY
F
BAD
REPLACE
ROTOR AND
STATOR
TEST 9 – TEST
STATOR
GOOD
PERFORM ROTOR
INSULATION
RESIST ANCE TEST
BAD
BAD
TEST 10 –
TEST ROTOR
ASSEMBLY
Problem 2 – Generator Produces Low Voltage at No-Load
TEST 11 – CHECK
AC OUTPUT
VOLTAGE
TEST 14 – ADJUST
VOLTAGE
REGULATOR
VOLTAGE O.K.,
BUT VOLTAGE IS
STLL LOW
TEST 12 – CHECK
LOW LOW
AC OUTPUT
FREQUENCY
FREQUENCY O.K.,
BUT VOLTAGE LOW
VOLTAGE AND FREQUENCY O.K.
GO TO “PROBLEM 1”
FLOW CHART - START
AT “TEST 4”
REPLACE
ROTOR ONLY
TEST 13 - ADJUST
ENGINE
GOVERNOR
GOOD
FREQUENCY
AND
VOLTAGE O.K.
STOP TESTS
Page 28
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