Yamaha EF4500iSE - Inverter Generator Setup guide

YAMAHA GENERATOR
THEORY & DIAGNOSTICS
GUIDE

2009
Yamaha Generator Theory and Diagnostics Guide
©2008 by Yamaha Motor Corporation, U.S.A.
December 2008
All rights reserved. Any reprinting
or unauthorized use
without written permission of
Yamaha Motor Corporation, U.S.A.
is expressly prohibited.
Printed in U.S.A.
Specifications, features and options are subject to
change without notice.
08-1169

TABLE OF CONTENTS
GENERATOR INFORMATION AND THEORY . . . . . . . . . . . . . . . . . . . . . . . . . . Section 1
Importance of Warranty Registrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Gasoline, Ethanol, Propane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Yamaha Inverter and Conventional Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
AC Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
12 Volt DC Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Voltage and Frequency Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Control Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Yamaha Generator Inverter System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Model Name Clarification YG/EF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
Model Introduction Year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-25
Extension Cord Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
High Altitude Jetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Special Diagnostic Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-28
GENERATOR DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Section 2
CONVENTIONAL GENERATOR DIAGNOSTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Determining if a Problem is Generator or Engine Related . . . . . . . . . . . . . . . . . . . . . 2-1
THEORY FOR NON-AVR TYPE GENERATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
THEORY FOR AVR TYPE GENERATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
AVR TROUBLESHOOTING CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16
NON-AVR TROUBLESHOOTING CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-17
TROUBLESHOOTING YAMAHA INVERTER GENERATORS . . . . . . . . . . . . . . . . . . . . 2-18
Ignition System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
Generator System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23
Engine Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28
Throttle Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
Charging System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35
Electric Starting System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38
Choke Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40
CURRENT MODEL SPECIFICATIONS AND WIRING DIAGRAMS. . . . . . . . . . . . . . . . Section 3
CONSUMER SERIES GENERATORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Inverter EF1000iS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Inverter EF2400iS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Inverter EF2800i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-18
Conventional EF2600. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25
Inverter EF3000iSE / B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33
Conventional EF4000DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-40
Inverter EF4500iSE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-50
Conventional EF5200DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-61
Inverter EF6300iSDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-71
Conventional EF6600DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-78
Conventional EF12000DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-87
INDUSTRIAL SERIES GENERATORS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-96
Inverter YG2800i . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-96
Conventional YG4000D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-104
Conventional YG5200D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-115
Conventional YG6600D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-125
Conventional YG6600DE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-135

1-1
Generator Information and Theory
Inverter generators differ from conventional genera-
tors in many ways. Inverter generators (Yamaha
models with Smart Throttle) do not rely on rpm to
control frequency (Hz). A highly specialized control
unit manages functions such as AC power modifica-
tion, rpm, circuit breaker protection, overload warn-
ing, and electrical output. Inverters do not need to
run at 3,600 rpm as most use a 3-phase multi-pole
stator. The inverter can produce more electricity with
fewer revolutions versus a single-phase conven-
tional generator. Typically, multi-pole coils work in
conjunction with numerous permanent magnets to
produce higher output at a lower rpm. Less revolu-
tions means higher fuel economy at lower outputs
and quieter operation.
Inverter generators also provide very stable and
clean power. The AC power produced by the multi-
pole coil is rectified into DC power – the control unit
then inverts the DC power back into AC power. This
final inversion creates clean, high-quality electricity.
In most cases, the electricity produced by a Yamaha
Inverter Generator is cleaner than most commercial/
residential power.
*PWM: Pulse Width Modulation is very clean and
stable output with a waveform distortion ratio of
2.5% or less. This low distortion ratio means the
output is cleaner than most commercial / residential
power, making it safe to run sensitive computer
equipment, televisions, and microchip-controlled
power tools.
GENERATOR INFORMATION AND THEORY
Introduction
The purpose of this manual is to provide training
and information for Yamaha dealers who may not be
familiar with Yamaha Generators. It will help build a
better understanding of how Yamaha Generators
work, basic troubleshooting techniques, and tips for
dealership personnel.
The Importance of Warranty Registration
It is important to warranty register every applicable
Yamaha product sold by your dealership. It is essen-
tial for customer satisfaction and insures your cus-
tomer can receive warranty service from an
authorized Yamaha dealer should the need arise.
Furthermore, warranty repairs performed on a
unit not warranty registered, will not be consid-
ered for reimbursement. Warranty registrations
also assist Yamaha with contact information in the
event of a recall or safety related issue.
Gasoline, Ethanol, Propane
All models of Yamaha generators run on regular
gasoline. Up to 10% ethanol is acceptable for run-
ning conditions. However, ethanol tends to attract
moisture which will lead to poor performance, so it
should not be used when storing a generator for
more than a few days.
Currently, there are no propane conversion kits
available that Yamaha Motor Corporation, U.S.A.
supports. Further, Yamaha recommends against the
use of any aftermarket generator propane conver-
sion kits.
Yamaha Inverter and Conventional Generators
The AC power created by conventional generators is
known as “raw” power. The electricity produced by
the stator (coils) and rotor (magnets) is delivered to
the outlet without modification of the AC sine wave.
In addition, conventional generators must run at
3,600 rpm in order to maintain the required 60 Hz
cycle. The power generated by a conventional gen-
erator depends on a constant engine speed. Any
fluctuation of rpm will create peaks (spikes) and val-
leys in the AC sine wave. Conventional generators
rely on large, heavy stators and rotors, which means
a heavier generator. Conventional generators are
typically less fuel efficient at low output levels
because they must run at 3,600 rpm at all times.
*
HIGH QUALITY
AC

1-2
Yamaha Generator Theory & Diagnostics Guide
Air intake Fuel tank cap Fuel gauge
Recoil starter Control panel Service hatch Exhaust MF Battery Service hatch
Main switch Economy control switch DC output AC receptacles
Fuel pet cock Choke knob Oil warning lamp
Output indicator
Over load indicator
USA specification
⎧ ⎪ ⎨ ⎪ ⎩
Yamaha inverter generators use a microcomputer-controlled sine wave inverter. Most inverter generators are
in a soundproof case, and designed in response to the diverse needs of the market today.
The Yamaha inverter generator supplies high quality electricity equivalent to household power supply.
NOTE: The EF3000iSE is used in this introduction section for explanation purposes.
Fuel petcock

1-3
■Throttle motor (stepping motor)
The throttle motor receives pulses from the con-
trol unit and opens or closes the throttle valve
approximately 0.7° per pulse.
Functions of the Electronic Governor
The inverter control unit is preprogrammed with the
ideal engine speed settings in relation to electrical
current output. It uses these settings as a cross-ref-
erence with the detected current output to control
the throttle motor (and consequently the throttle
valve) to adjust engine speed to an optimum level.
Therefore, the engine speed will always be at the
appropriate level according to the load on the sys-
tem.
With an inverter generator, even if the engine
speed changes it has no effect on the output
frequency.
The electronic governor system is maintenance-free
as it cannot be adjusted externally.
Power Generation
Stage 1 The rectifier circuit converts three- phase
AC into DC and it maintains stable DC
voltage using a constant voltage circuit.
Stage 2 The constant voltage DC current is
stored in a condenser.
Stage 3 The PWM, Pulse Width Modulator,
inverter circuit generates a stable sine
wave AC current.
Stage 4 The filter circuit further smoothens the
sine wave of the AC current and reduces
electrical noise.
Protective functions:
■Overload (over current) protection device
The control unit has similar function to conven-
tional NFB (no fuse breaker). When the output
current exceeds a specified amperage, AC out-
put is interrupted.
■Overheat protection
When the internal temperature of the control
unit becomes abnormally high, AC output is
interrupted.
■Over-voltage protection device
AC output is interrupted when excessive current
flows into the generator from an outside power
source causing voltage to rise in the control
unit.
Other Functions of the Control Unit:
Throttle Control – Control unit commands the throttle
motor to adjust engine speed automatically in accor-
dance with the amount of the electrical consump-
tion.
Electronic Governor
An electronic governor takes the place of a conven-
tional mechanical governor, and opens and closes
the carburetor throttle valve electrically.
Components and functions:
■Inverter control unit
The control unit constantly monitors AC output
and adjusts the throttle motor to produce the
necessary engine speed.
Generator Information and Theory
Stepping motor
EF3000iSE new model guide 3/14/03 4:20 PM Page 3
Resistance 250ΩTerminal:F3-1, 3-5, 3-2, 3-4
500ΩTerminal: 1-5, 2-4
Throttle valve position:
During assembly:Close
During engine starting:Open
Economy Control Characteristics
EF3000iSE new model guide 3/14/03 4:20 PM Page 4
STEPPING MOTOR
ENGINE rpm
DETECTOR
THROTTLE
CONTROL

1-4
Yamaha Generator Theory & Diagnostics Guide
AC OUTPUTS
There are two levels of output available from Yamaha
generators:
1. Peak Output (short period of time).
2. Rated Output (continuous duty).
In normal operation of course, these levels would
merge. The built-in Thermal or Nonfuse Breakers
(NFB) are designed to protect against harmful over-
loads, while allowing for these different levels. The
length of time the breaker allows the generator to
produce a particular level without interrupting the
current flow varies. This flexibility permits the gen-
erator to be used for a wide variety of applications:
1. The stated peak output is the amount of cur-
rent that can be utilized for short time periods
before the NFB disconnects the output. This
output level allows for jobs of short duration,
requiring maximum output (tool startup).
2. The rated output is the amount of current the
generator can supply for continuous operation.
12 Volt DC Output
The DC output is intended only to charge a 12-volt
battery. If any 12-volt devices should be connected
to a 12V battery and never to the 12V plug on the
generator. It is possible that a device could be dam-
aged if it is connected directly to a generator.
The DC output is controlled only by the capability,
condition, and state of charge of the battery.
Voltage and Frequency Standards
In the U.S., standard commercial electricity is deliv-
ered at 110~120 V AC, and 220~240 V AC. The
electrical frequency standard is 60 cycles per sec-
ond (60 Hz).
Multi-pole Alternator Features
Used in Inverter Generators
The combination of ferrite magnets in the rotor and
multi-pole stator provides a compact and high per-
formance alternator.
High-frequency multi-pole alternator features:
16-pole rotor
24-pole stator coil
3-phase AC power generation
Exhaust pipe
Engine
Alternator
Muffler
Fuel tank
Control unit
Recoil starter
Battery
EF3000iSE/EF3000iSEB
Control unit
*
EF3000iSE new model guide 3/14/03 4:20 PM Page 2
EF3000iSE/EF3000iSEB
CONTROL UNIT
Reference information:
Ferrite magnets are magnetically stable and have a
strong coercive force and so do not become demag-
netized. While they have excellent corrosion resis-
tance, they are also brittle due to the way they are
produced. Great care must be taken when assem-
bling them as jarring or shocks of force can
adversely affect their efficiency and/or cause
breakage.
Control Unit
The control unit is a sealed unit.
Functions:
AC power generation
Electronic governor (throttle control)
Economy control program
Self-protective function
Over current
Over voltage
High temperature

1-5
Section
Yamaha Generator Inverter System
The control unit and multi-pole alternator cooperate to generate AC output. The inverter, controlled by a 16-bit
microcomputer, is a Pulse Width Modulation (PWM) sine wave inverter.
1. The generator’s output frequency remains unchanged even when the engine speed varies.
2. The output voltage is stable.
3. The output waveform is a sine wave with a distortion ratio of less than 2.5%, equivalent to household
electricity.
Control unit
*
EF3000iSE new model guide 3/14/03 4:20 PM Page 2
PRINCIPLES OF POWER GENERATION WITH AN INVERTER PORTABLE GENERATOR
*An alternator that uses highly efficient ferrite magnets generates three-phase AC.
 •120VModel:AC135to225V,300to550Hz
 •230VModel:AC260to488V,300to550Hz
Synchronous Generator — Theory & Troubleshooting
4–11
THEORY FOR DAMPER WINDINGS
For generators with a condensor control
(non AVR), the electricity output is not
a very high quality sine-wave, but does
meet most requirements for "rough use"
power demand.
When the generator begins to get a load
applied, the sine wave is altered by the
load voltage running through the stator and
inducing its own magnetic field, which alters
the path of the rotor coil’s magnetic flux.
The altered flux line distorts the output sine.
This altered sine wave can cause some
problems for appliances with microcomputer
or are sensitive to waveform "ripples".
Sometimes, the ripples are seen as freque-
-ncy problems and disturb the appliance.
Condenser Winding Sine Wave
Inverter Sine Wave
Damper Winding Sine Wave
Synchronous Generator — Theory & Troubleshooting
4–11
THEORY FOR DAMPER WINDINGS
For generators with a condensor control
(non AVR), the electricity output is not
a very high quality sine-wave, but does
meet most requirements for "rough use"
power demand.
When the generator begins to get a load
applied, the sine wave is altered by the
load voltage running through the stator and
inducing its own magnetic field, which alters
the path of the rotor coil’s magnetic flux.
The altered flux line distorts the output sine.
This altered sine wave can cause some
problems for appliances with microcomputer
or are sensitive to waveform "ripples".
Sometimes, the ripples are seen as freque-
-ncy problems and disturb the appliance.
Condenser Winding Sine Wave
Inverter Sine Wave
Damper Winding Sine Wave
CONVENTIONAL SINE WAVE INVERTER SINE WAVE

1-6
Yamaha Generator Theory & Diagnostics Guide
2. When changes in voltage cannot be accepted.
3. When charging batteries.
Economy switch ON: 2800 rpm (with no load)
Economy switch OFF: 3550 rpm
The engine will run at 2800 rpm with economy
switch turned on, if the electrical consumption is
below 1/4 of its rated output.
When a light and electric motor are connected to the
generator at the same time, turning one of the
devices on and off causes a change in voltage and
could have an adverse effect on the other device.
In these kinds of cases, first turn the economy
switch off before use.
Throttle valve operation:
■The throttle valve is fully opened when the
engine is not running.
■When the engine is started with no load, the
throttle valve will be set in an almost completely
closed position as soon as the engine is started.
(When the economy switch is “ON,” it will be in
a position to maintain 2800 rpm.)
■The engine speed will be adjusted according to
the requirements of the load on the system.
■The throttle stops at the fully opened position
when the engine is turned off in order to prepare
for the next attempt to start the engine.
In temperatures of 0° or below, the engine will auto-
matically run at 3550 rpm for three minutes for
warming up purposes, even when the economy
control switch is turned ON.
Throttle Motor
Caution during resistance measurement:
Do not allow the lead wire of the tester to touch the
next terminal when measuring the resistance
between terminals.
Caution during assembly:
To prevent damage to the throttle valve when reas-
sembling the carburetor, re-install the carburetor
with the throttle valve fully opened.
If the engine is difficult to start after the carbure-
tor is installed, fully open the throttle valve by
hand and then start the engine.
Economy Control Operation and Features
Because output frequency of an inverter generator
is unrelated to the engine speed, it is possible to use
a wide range of engine speed.
It also becomes possible to use low engine speed to
meet a low electrical consumption.
The control unit commands the throttle motor built
into the carburetor to control the throttle valve, which
gives it the ability to continuously control the engine
speed, which in turn makes the economy control
system possible.
However, the economy control switch should be
turned off in case of the following occasions:
1. When operating an electric motor, such as
water pump, which requires a large starting cur-
rent.
Resistance 250ΩTerminal:F3-1, 3-5, 3-2, 3-4
500ΩTerminal: 1-5, 2-4
Throttle valve position:
During assembly:Close
During engine starting:Open
Economy Control Characteristics
EF3000iSE new model guide 3/14/03 4:20 PM Page 4
Resistance 250ΩTerminal:F3-1, 3-5, 3-2, 3-4
500ΩTerminal: 1-5, 2-4
Throttle valve position:
During assembly:Close
During engine starting:Open
Economy Control Characteristics
EF3000iSE new model guide 3/14/03 4:20 PM Page 4
Economy Control Characteristics
of an EF3000iSE/B

1-7
The frequency variation of Yamaha inverter gen-
erators is less than 0.1%.
Voltage Variation
The output voltage with no load is approximately
10% higher than rated voltage for a case of conven-
tional synchronous type generators to achieve the
rated voltage when full rated load is connected. Thus
the voltage variation occurs due to the change in
engine speed and the influence of the internal resis-
tance.
However, adapting an inverter system, the voltage
variation can be minimized, because the output volt-
age cannot be influenced directly from engine
speed.
The voltage variation of Yamaha inverter genera-
tors is smaller than 3%.
The waveform distortion rate of Yamaha inverter
generators is smaller than 2.5%.
Continuous Running Time
EF3000iSE is able to run for 20.5 hours with 1/4
load with fuel tank full, when economy control switch
is on.
With rated load: 8.0 hours
With 1/4 load: 20.5 Hours
Refer to Section 3 for model specific run times and
rated load information.
Frequency Variation
Conventional synchronous generators have an
engine speed with no load set at approximately 6%
higher than rated engine speed (3600rpm for 60 Hz)
to maintain rated frequency when full rated load is
applied. This is the reason why no-load frequency is
slightly higher than rated frequency.
However, adapting an inverter system, which gener-
ates genuine sine wave electricity, the frequency
variation of an inverter generator is not influenced by
the engine speed. Therefore, an inverter generator
provides constant AC output frequency even if the
load changes which is equivalent quality to the com-
mercial power supplies.
Generator Information and Theory
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1-8
Yamaha Generator Theory & Diagnostics Guide
Electronic Breaker
As opposed to the non-fuse breaker (NFB) used in
synchronous type generators, Yamaha inverter gen-
erators use an electronic breaker circuit housed in
the control unit. When output from the control unit
exceeds a specific limit, output is automatically inter-
rupted to protect the generator from damage.
The control unit is designed to continuously monitor
the output current for overloads, and if the current
overload continues longer than a specified time,
output is interrupted.
When using induction motors or similar devices
(such as underwater pumps) which require a large
starting current with the generator, the current will
not be interrupted even if the starting current
exceeds several times the generator’s rated output.
Only when the large over current continues longer
than a specified time, the control unit will interrupt
the circuit, and in this way it resembles a mechani-
cal NFB.
The engine must be stopped and power interrupted
to the control unit in order for the system to reset
after the electronic breaker has activated.
NOTE: If a device’s power switch is ON when it is
connected the generator and the generator is sub-
sequently started, the device may unexpectedly
activate or start up as a result, creating a potentially
dangerous situation.
Instantaneous Frequency Fluctuation &
Instantaneous Voltage Drop
■Momentary frequency fluctuation:
The frequency and voltage fluctuates momen-
tarily when the load is altered if the engine can-
not keep up with the load changes in the case
of conventional synchronous generators.
In contrast the momentary frequency fluctuation
of Yamaha inverter generators is as stable as
the commercial power source with this new
inverter system.
The frequency fluctuation rate ofYamaha inverter
generators is less than 0.1%.
■Momentary voltage drop:
However, the momentary voltage drop occurs,
when large electric load is turned on. This is
caused by the fact that the electric energy
stored in the condenser runs short momentarily
until the engine speed picks up to sufficient
engine speed to compensate the energy short-
age in the condenser. The ratio of such momen-
tary voltage drop and the rated voltage is
defined as momentary voltage drop rate. The
momentary voltage drop rate of Yamaha inverter
generators is usually less than 20%. Naturally,
the smaller the load capacity is applied, the
smaller the momentary voltage drop becomes.
In case of incandescent lamps, large amounts
of current flow the moment it is switched on. The
rush current may be as large as 10 times the
rated current of the lamp. Therefore, when a
large wattage incandescent lamp(s) are switched
on, the momentary voltage drop is greater.
Characteristics of Electronic Breaker
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1-9
Generator Information and Theory
Output Indicator
When the generator is running normally and gener-
ating power, this indicator is lit green.
When using a device which requires a large starting
current, the overload warning light (red) and output
indicator (green) will temporarily light simultane-
ously. This operation is normal.
After the connected device has started up, the over-
load warning light (red) will turn off, while the output
indicator (green) will continue to be lit.
Oil Warning Lamp
As with all Yamaha generators, the engine will shut
off automatically when the oil level decreases to a
specified level.
When this happens and the recoil starter is pulled,
the engine will not start and the oil warning light will
turn on.
Control Panel
Refer to Section 3 for model specific control panel
diagrams.
Indicators
Overload Warning Lamp
During power generation, if a problem occurs with a
connected device, there is an overload, or the
inverter control unit overheats, the electronic breaker
will be activated and interrupt power output to pro-
tect the generator and/or connected devices.
■ When the electronic breaker operates:
The engine continues to run, but the control unit
stops output
The output indicator (green) turns off
The overload indicator (red) turns on
■When the overload warning light turns on:
Stop the engine.
Verify the required load of the connected device,
and reduce to the rated load of the generator if
necessary. Verify whether or not there is a prob-
lem with a connected device. (A possible cause
of excessive current drain.)
Check for foreign matter in the cooling air inlet
and areas around the control unit which could
block incoming air.
■To return the generator to normal output
operation:
Temporarily stopping the engine and re-starting
automatically resets the system to its original
state. (The system cannot be reset unless power
to the control unit is interrupted by stopping the
engine.)

1-10
Yamaha Generator Theory & Diagnostics Guide
Ventilation
Be aware of the surroundings where generators are being used. Three (3) feet of clear space is necessary for
safe operation. Adequate ventilation is also necessary, as the generator’s engine needs fresh air for the intake,
and the exhaust must be safely vented. Refer to the Owner’s Manual for complete information.
Lubrication System
The engine units of all Yamaha conventional and inverter generators use a splash type oiling system.
Cooling System
The centrifugal fan equipped on the rotor performs forced air cooling of the system over the path listed below.
Each part of the system is therefore continuously kept at a stable operating temperature with only a single
fan.
Cooling systems will vary from one model to another. The EF3000iSE is shown here as an example. Refer to
the Owner’s or Service Manual for model specific information.
• Coolingairpath
• Controlunitcover
• Controlunit
• Alternator
• Engine(cylinder)
• Muffler
Generator Storage
To prepare a Yamaha generator for storage follow these basic
procedures:
• The carburetor float bowl should be emptied using the
float bowl drain screw located on the float bowl.
• Thefueltankshouldbefullandcontaintheproperamount
of a fuel stabilizer.
• The unit should be covered and stored in a cool dry
place.
• RefertotheOwner’sorServiceManualforcompletestor-
age information.
– 10 –
Rotor Ass’y
Muffler
Cooling fan
Generator
cooling
air inlet
Flow of cooling air over generator and muffler
Controller
Cooling air inlets
Battery
Cooling air inlets
Recoil starter
Muffler
Generator fan
Generator cooling air inlet
Overall flow of cooling air
Control unit
Intake box
Cooling
air inlets
Fan case
Cooling fan
Flow of cooling air over generator and muffler
EF3000iSE new model guide 3/14/03 4:20 PM Page 10
– 10 –
Rotor Ass’y
Muffler
Cooling fan
Generator
cooling
air inlet
Flow of cooling air over generator and muffler
Controller
Cooling air inlets
Battery
Cooling air inlets
Recoil starter
Muffler
Generator fan
Generator cooling air inlet
Overall flow of cooling air
Control unit
Intake box
Cooling
air inlets
Fan case
Cooling fan
Flow of cooling air over generator and muffler
EF3000iSE new model guide 3/14/03 4:20 PM Page 10
– 10 –
Rotor Ass’y
Muffler
Cooling fan
Generator
cooling
air inlet
Flow of cooling air over generator and muffler
Controller
Cooling air inlets
Battery
Cooling air inlets
Recoil starter
Muffler
Generator fan
Generator cooling air inlet
Overall flow of cooling air
Control unit
Intake box
Cooling
air inlets
Fan case
Cooling fan
Flow of cooling air over generator and muffler
EF3000iSE new model guide 3/14/03 4:20 PM Page 10

1-11
Generator Information and Theory
DC 12V Output
DC output is provided on Yamaha inverter generators exclusively for battery charging.
Rated output: DC 12V ~ 12A (12V ~ 8.3A for Canada)
DC 12V circuit is entirely separated from AC circuit.
Economy control switch must be turned off while charging a battery, as the engine speed 3550 rpm is required
to generate rated DC-output.
The total electric consumption of both the AC and the DC output should not exceed the total rated output of
the generator, which is 2800 Va, when both output are used together.
Rectifier (for DC output)
– 11 –
(+)
(–)
(~)
(~)
Polarity of rectifier 7VU-87105-00
Rectifier
G/Y R/W
B/W
B
B
R
R
R
RR
R
RR
R
M
R
R
R
B
B
L
L
L
L
B
R
RR
R R
R
R
G
GGG
G
G
O
O
O
O
O
O O
O
O
OO O
O
O
O
B/W
O
O
O
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
YY
Y
YY
Y
YY
L
L
R
G
L
LL
L
L
L
O
O
O
L
L
L
W
W
W
W
B
B
W
W
R/W
G/Y
G/Y
G/Y
Gy
G/Y
G/Y
G/Y
G/Y
B/W
B/W
B/W
B/W
B/W
R/W
R/W
B/W
B
B/W
B/W
B/W
R
R
R
R
R
O
Y
R
R
B
B
B
B
BB
R
Br
Br
Br Br
Br
Br
Br
Br
OFF
ON
START
RR
R
q
r
w
e
@1
@2
@3
@4
t
@0
!9
!6
!7
!5
i
!3
!2
!8
!4
!1
!0
o
uu
y
@5
1Main coil
2Sub coil
3DC coil
4DC rectifier
5Control unit
6AC pilot light
7AC receptacle
8Ground (Earth) terminal
9Economy control switch
0Overload indicator light
qDC receptacle
wDC protector (breaker)
eEngine switch
rOil warning light
tSpeed limiter assenbly
yOil level gauge
uT.C.I. unit
iSpark plug
oT.C.I. magneto
pStepping motor
aDC-DC converter
sRectifier
dBattery
fStarter relay
gStarter motor
EF3000iSE new model guide 3/14/03 4:20 PM Page 11
– 11 –
(+)
(–)
(~)
(~)
Polarity of rectifier 7VU-87105-00
Rectifier
G/Y R/W
B/W
B
B
R
R
R
RR
R
RR
R
M
R
R
R
B
B
L
L
L
L
B
R
RR
R R
R
R
G
GGG
G
G
O
O
O
O
O
O O
O
O
OO O
O
O
O
B/W
O
O
O
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
YY
Y
YY
Y
YY
L
L
R
G
L
LL
L
L
L
O
O
O
L
L
L
W
W
W
W
B
B
W
W
R/W
G/Y
G/Y
G/Y
Gy
G/Y
G/Y
G/Y
G/Y
B/W
B/W
B/W
B/W
B/W
R/W
R/W
B/W
B
B/W
B/W
B/W
R
R
R
R
R
O
Y
R
R
B
B
B
B
BB
R
Br
Br
Br Br
Br
Br
Br
Br
OFF
ON
START
RR
R
q
r
w
e
@1
@2
@3
@4
t
@0
!9
!6
!7
!5
i
!3
!2
!8
!4
!1
!0
o
uu
y
@5
1Main coil
2Sub coil
3DC coil
4DC rectifier
5Control unit
6AC pilot light
7AC receptacle
8Ground (Earth) terminal
9Economy control switch
0Overload indicator light
qDC receptacle
wDC protector (breaker)
eEngine switch
rOil warning light
tSpeed limiter assenbly
yOil level gauge
uT.C.I. unit
iSpark plug
oT.C.I. magneto
pStepping motor
aDC-DC converter
sRectifier
dBattery
fStarter relay
gStarter motor
EF3000iSE new model guide 3/14/03 4:20 PM Page 11

1-12
Yamaha Generator Theory & Diagnostics Guide
FIRST-AID PROCEDURES: If your skin or clothes
come in contact with the electrolyte, wash them
with a large amount of water immediately. If it
enters your eyes, wash with a large amount of
water and consult the doctor immediately.
• Whenhandlingabattery,keepgoodventila-
tion and keep electric sparks, like from
short-circuit, away. Also, keep fire away.
Explosion might happen because a flamma-
ble gas occurs from the battery.
• The battery electrolyte is diluted sulfuric
acid. If it comes in contact with your eyes or
skin, the affected part will be burnt. If it
should happen, wash the part with a large
amount of water for at least 15 minutes and
consult the doctor immediately.
Battery Charging
■Conditions of use of the DC power supply
■Charging a 12V battery
Do not use for other than charging a 12V
battery.
The time taken to charge a battery depends on how
the battery is discharged. Charging is complete
when the specific gravity of the battery is 1.26~1.28.
Check the specific gravity in every hour or so.
A 40AH battery of a compact car which is half dis-
charged will be almost fully charged in about 3
hours. Be sure to check the level of the electrolyte.
Do not take energy from the battery nor run the
starter when the battery is being charged. This could
cause a large current to flow through the generator
coil, burning it.
■Precautions for charging the battery
The battery will produce a flammable gas. The
wrong handling might result in explosion or
serious injuries. Be sure to observe the follow-
ing when charging a battery.
1. Keep fire and electric sparks away. Explosion
might happen.
2. Secure a good ventilation where the battery
is charged. Otherwise, explosion might hap-
pen.
3. Be very careful to handle the electrolyte
(diluted sulfuric acid). It will burn anything,
so keep it away from your eyes, skin and
clothes.
4. Before charging a battery, remove all cords
connected to the battery, doing it first from
the negative side. When reconnecting, do
the positive side first. If you do it incorrectly,
a short-circuit could result.
WARNING
WARNING

1-13
Generator Information and Theory
EF2800i AC-CDI
The Yamaha EF2800i Inverter generator is the only
generator in the Yamaha line-up to use an AC-CDI.
A CDI unit which uses AC power to charge the con-
denser is referred to as an AC-CDI.
Taking the low voltage power generated by the
charge coil (which is wound around a single stator
core in the multi-polar alternator), a voltage booster
circuit boosts the voltage in the CDI in order to
charge the condenser. In a typical CDI system, volt-
age of approximately 200~400 volts is generated by
the charge coil.
The advantages are the charge coil can be made
both lighter and smaller. Also a heavier wire can be
used for the charge coil to increase its reliability.
An overrun limiter is incorporated into the EF2800i’s
AC-CDI unit.
The ignition spark is regulated to prevent engine
speed overrun when the engine speed exceeds
4500 rpm.
A new oil warning system was designed to match
the new CDI system, while maintaining the same
function of the conventional oil warning system.

1-14
Yamaha Generator Theory & Diagnostics Guide
The EF1000iS
Exclusive to the EF1000iS, the double-coil system is
a unique design that adds to the main coil a second
coil specifically for running at lower rpm. Increasing
the number of coils in this second low-speed coil
enables it to generate optimum electricity when the
engine is running at lower rpm. When the engine
rpm increases, however, these extra coils become
unwanted resistance that reduced generating effi-
ciency. Thus, a system has been adopted that auto-
matically selects the right coil in relation to the
engine rpm; the low speed coil becomes the main
generating coil at low rpm and the main coil from
middle to high rpm. This is a Yamaha-exclusive tech-
nology that might be called a dual-stage system to
accommodate low and middle range rpm. The result
is a generating system that can provide optimum
electricity supply that is stable even at low rpm and
thus run with less noise and better fuel economy.
EF1000iS

1-15
Generator Information and Theory
Power Boost Technology
EF3000iSEB is equipped with a DC-DC converter, which supplies supplemental electric current to the inverter
control unit to boost up the generator output by an additional 500 watts for maximum 10 seconds. This feature
is exclusive on the EF3000iSEB.
– 14 –
Control Unit
DC-DC converter
EF3000iSE new model guide 3/14/03 4:20 PM Page 14
DC-DC Converter (Power Boost Technology)
The DC-DC converter is an electrical device to step
up DC voltage. The EF3000iSEB DC-DC converter
steps up the battery voltage from 12 volts to 190
volts.
DC-DC converter is automatically activated to
increase generator output when the AC output cur-
rent exceeds 20 amps and the voltage at the con-
denser inside the control unit drops down to below
190 volts.
The power source is a 12-V battery installed in the
generator to operate the starter motor. DC-DC con-
verter works for maximum 10 seconds, only when a
large amount of starting current is needed and
increases maximum output of generator from 3000
VA to 3200 VA temporarily.
Specifications of DC-DC converter
1. DC input 12V Battery
2. DC output DC190V
3. Rated DC current 2.53 A
– 14 –
Control Unit
DC-DC converter
EF3000iSE new model guide 3/14/03 4:20 PM Page 14

1-16
Yamaha Generator Theory & Diagnostics Guide
Overload Indicator Lamp:
The DC-DC converter is turned on automatically,
when the generator output exceeds over 180% of its
rated load to boost generator output to assist the
starting current of the load, such as an air condi-
tioner.
When the DC-DC converter is turned on automati-
cally, the generator is obviously overloaded, thus the
overload indicator lamp blinks quickly with 0.5-sec-
ond interval for 10 seconds. And the lamp blinks
slowly with 1-second interval for 3 minutes and 50
seconds. During this period, the DC-DC converter is
prevented from rebooting to prevent the battery from
over-discharged.
– 15 –
Green LEDRed LEDDesignation
ON OFF Standby mode
Blink OFF Output (for 10 seconds maximum)
OFF Blink For 10 seconds after shutdown
OFF ON Alarm mode
⎫ ⎪ ⎪ ⎪ ⎪ ⎬ ⎪ ⎪ ⎪ ⎪ ⎭
EF3000iSE new model guide 3/14/03 4:20 PM Page 15
Designation of LED Indicators:
DC-DC converter unit is equipped with two indicator lamps (LED) on the unit. When the DC-DC converter is
activated automatically, indicator lamps are lit or blink to designate the state of the system. The designations
of indicator lamps are listed in the table below.
– 15 –
Green LEDRed LEDDesignation
ON OFF Standby mode
Blink OFF Output (for 10 seconds maximum)
OFF Blink For 10 seconds after shutdown
OFF ON Alarm mode
⎫ ⎪ ⎪ ⎪ ⎪ ⎬ ⎪ ⎪ ⎪ ⎪ ⎭
EF3000iSE new model guide 3/14/03 4:20 PM Page 15
NOTE: The red LED turns ON and interrupts DC-DC converter output automatically to protect the component,
when any of the abnormal operating conditions is detected, and returns to normal operation automatically as
soon as the abnormality is recovered.
Abnormal conditions are:
1. Too high temperature in the component
2. Too low battery voltage, below 9.5V
3. Too high battery voltage, over 18V