Normal Operating Range-20°F (-28.8°C) to 104°F (40°C)
005243 & 005283
005244 & 005284
Group 26
12 Volts and
525 Cold-cranking
Amperes Minimum
* Maximum wattage and current are subject to and limited by such factors as fuel Btu content, ambient temperature, altitude, engine power and condition, etc.Maximum 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.
** Load current values shown for 120 volts are maximum TOTAL values for two separate circuits.The maximum current in each circuit must not exceed the value stated for 240 volts.
*** Circuits to be moved from main panel to transfer switch load center must be protected by same size breaker. For example, a 15 amp circuit in main panel must be a 15 amp circuit in
This Diagnostic Repair Manual has been prepared
especially for the purpose of familiarizing service personnel with the testing, troubleshooting and repair of
air-cooled, prepackaged automatic standby generators. Every effort has been expended to ensure that
information and instructions in the manual are both
accurate and current. However, Generac reserves the
right to change, alter or otherwise improve the product
at any time without prior notification.
The manual has been divided into seven PARTS.
Each PART has been divided into SECTIONS. Each
SECTION consists of two or more SUBSECTIONS.
It is not our intent to provide detailed disassembly and
reassemble instructions in this manual. It is our intent
to (a) provide the service technician with an under
standing 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.
ITEM NUMBER:
Many home standby generators are manufactured
to the unique specifications of the buyer. The Model
Number identifies the specific generator set and its
unique design specifications.
PART 1
Item #
Serial
Volts
Amps
Watts
-
1 PH, 60 HZ, RPM 3600
MAX OPERATING AMBIENT
FOR STANDBY SERVICE
0055555
1234567
120/240 AC
108.3/108.3
13000
CLASS F INSULATION
TEMP - 120F/49C
GENERAL INFORMATION
NEUTRAL FLOATING
MAX LOAD UNBALANCED - 50%
GENERAC POWER SYSTEMS
WAUKESHA, WI
MADE IN U.S.A.
SERIAL NUMBER:
Used for warranty tracking purposes.
Figure 1. A Typical Data Plate
Page 10
GENERAL INFORMATION
PART 1
SECTION 1.2
PREPACKAGED INSTALLATION BASICS
INTRODUCTION
Information in this section is provided so that the service technician will have a basic knowledge of installation requirements for prepackaged home standby
systems. Problems that arise are often related to poor
or unauthorized installation practices.
A typical prepackaged home standby electric system
is shown in Figure 1 (next page). Installation of such a
system includes the following:
• Selecting a Location
• Grounding the generator.
• Providing a fuel supply.
• Mounting the load center.
• Connecting power source and load lines.
• Connecting system control wiring.
• Post installation tests and adjustments.
SELECTING A LOCATION
Install the generator set as close as possible to the
electrical load distribution panel(s) that will be powered by the unit, ensuring that there is proper ventilation for cooling air and exhaust gases. This will reduce
wiring and conduit lengths. Wiring and conduit not
only add to the cost of the installation, but excessively
long wiring runs can result in a voltage drop.
Control system interconnections non-prepackaged
generator consist of N1 and N2, and leads 23 and
194. Control system interconnection leads must be
run in a conduit that is separate from the AC power
leads. Recommended wire gauge size depends on
the length of the wire:
Max. Cable LengthRecommended Wire Size
460 feet (140m)No. 18 AWG.
461 to 730 feet (223m)No. 16 AWG.
731 to 1,160 feet (354m)No. 14 AWG.
1,161 to 1850 feet (565m)No. 12 AWG.
GROUNDING THE GENERATOR
The National Electric Code requires that the frame
and external electrically conductive parts of the generator be property connected to an approved earth
ground. Local electrical codes may also require proper grounding of the unit. For that purpose, a grounding lug is attached to the unit. Grounding may be
accomplished by attaching a stranded copper wire of
the proper size to the generator grounding lug and to
an earth-driven copper or brass grounding-rod (electrode). Consult with a local electrician for grounding
requirements in your area.
THE FUEL SUPPLY
Prepackaged units with air-cooled engines were operated, tested and adjusted at the factory using natural
gas as a fuel. These air-cooled engine units can be
converted to use LP (propane) gas by making a few
adjustments for best operation and power.
LP (propane) gas is usually supplied as a liquid in
pressure tanks. Both the air-cooled and the liquid
cooled units require a “vapor withdrawal” type of fuel
supply system when LP (propane) gas is used. The
vapor withdrawal system utilizes the gaseous fuel
vapors that form at the top of the supply tank.
The pressure at which LP gas is delivered to the
generator fuel solenoid valve may vary considerably,
depending on ambient temperatures. In cold weather,
supply pressures may drop to “zero”. In warm weath
er, extremely high gas pressures may be encountered.
A primary regulator is required to maintain correct gas
supply pressures.
Current recommended gaseous fuel pressure at the inlet
side of the generator fuel solenoid valve is as follows:
LPNG
Minimum water column10 inches5 inches
Maximum water column12 inches7 inches
A primary regulator is required to ensure that proper
fuel supply pressures are maintained.
DANGER: LP AND NATURAL GAS ARE BOTH
Use of a flexible length of hose between the generator fuel line connection and rigid fuel lines is required.
This will help prevent line breakage that might be
caused by vibration or if the generator shifts or settles.
The flexible fuel line must be approved for use with
gaseous fuels.
Flexible fuel line should be kept as straight as possi
ble between connections. The bend radius for flexible
fuel line is nine (9) inches. Exceeding the bend radius
can cause the fittings to crack.
HIGHLY EXPLOSIVE. GASEOUS FUEL LINES
MUST BE PROPERLY PURGED AND TESTED
FOR LEAKS BEFORE THIS EQUIPMENT IS
PLACED INTO SERVICE AND PERIODICALLY
THEREAFTER. PROCEDURES USED IN
GASEOUS FUEL LEAKAGETESTS MUST
COMPLY STRICTLY WITH APPLICABLE FUEL
GAS CODES. DO NOT USE FLAME OR ANY
SOURCE OF HEAT TO TEST FOR GAS LEAKS.
NO GAS LEAKAGE IS PERMITTED. LP GAS IS
HEAVIER THAN AIR AND TENDS TO SETTLE IN
LOW AREAS. NATURAL GAS IS LIGHTER THAN
AIR AND TENDS TO SETTLE IN HIGH PLACES.
EVEN THE SLIGHTEST SPARK CAN IGNITE
THESE FUELS AND CAUSE AN EXPLOSION.
THE TRANSFER SWITCH / LOAD CENTER
A transfer switch is required by electrical code, to prevent electrical feedback between the utility and standby power sources, and to transfer electrical loads from
one power supply to another safely.
PREPACKAGED TRANSFER SWITCHES:
Instructions and information on prepackaged transfer
switches may be found in Part 3 of this manual.
Page 11
-
-
SECTION 1.2
PREPACKAGED INSTALLATION BASICS
BAR
NEUTRAL
100A OR 200A
HOUSE MAIN
SERVICE
GROUND
PANEL BOARD
TRANSFER SWITCH)
GENERAC UL LISTED
(8, 10, 12 OR 16 CIRCUIT
PART 1
CONNECTION OF GENERATOR
TO EXTERNAL CONNECTION PANEL
GENERAL INFORMATION
TO HOUSE BRANCH
CIRCUITS SPLICED
USING WIRE NUTS
GROUND
CIRCUITS
EMERGENCY
STUD
NEUTRAL
40A OR 70A 2-POLE
CIRCUIT BREAKER
194N1 N2 23
2 POLE
EARTH
GENERATOR OUTPUT CIRCUIT BREAKER
SPIKE
CONNECTION BOX
4 PIN
EXTERNAL CUSTOMER
CONNECTOR
Page 12
Figure 1. Typical Prepackaged Installation
GENERATOR GROUND
(LOCATED ON THE REAR OF UNIT)
GENERAL INFORMATION
PART 1
SECTION 1.2
PREPACKAGED INSTALLATION BASICS
POWER SOURCE AND LOAD LINES
The utility power supply lines, the standby (generator) supply lines, and electrical load lines must all be
connected to the proper terminal lugs in the transfer
switch. The following rules apply: In 1-phase systems
with a 2-pole transfer switch, connect the two utility
source hot lines to Transfer Switch Terminal Lugs N1
and N2. Connect the standby source hot lines (E1,
E2) to Transfer Switch Terminal Lugs E1 and E2.
Connect the load lines from Transfer Switch Terminal
Lugs T1 and T2 to the electrical load circuit. Connect
UTILITY, STANDBY and LOAD neutral lines to the
neutral block in the transfer switch.
SYSTEM CONTROL INTERCONNECTIONS
Prepackaged home standby generators are equipped
with a terminal board identified with the following terminals: (a) UTILITY 1, (b) UTILITY 2, (c) 23, and (d)
194. Prepackaged load centers house an identically
marked terminal board. When these four terminals
are properly interconnected, dropout of utility source
voltage below a preset value will result in automatic
generator startup and transfer of electrical loads to
the “Standby” source. On restoration of utility source
voltage above a preset value will result in retransfer
back to that source and generator shutdown.
The installer must ensure that the home standby generator has been properly installed. The system must
be inspected carefully following installation. 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.
Prior to initial startup of the unit, the installer must
ensure that the engine-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 rec
ommended oil.
FUEL REQUIREMENTS
With LP gas, 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 specifications of the 1997
California Air Resources Board for tamper-proof dual
fuel systems. The unit will run on natural gas or LP
gas, but it has been factory set to run on natural gas.
Should the primary fuel need to be changed to LP
gas, the fuel system needs to be reconfigured. See
the Reconfiguring the Fuel System section for instruc
tions on reconfiguration of the fuel system.
Recommended fuels should have a Btu content of
at least 1,000 Btus per cubic foot for natural gas; or
at least 2,520 Btus per cubic foot for LP gas. Ask the
fuel supplier for the Btu content of the fuel.
Required fuel pressure for natural gas is 5 inches to
7 inches water column (0.18 to 0.25 psi); and for liq
uid propane, 10 inches to 12 inches of water column
(0.36 to 0.43 psi).
NOTE: All pipe sizing, construction and layout
must comply with NFPA 54 for natural gas applica
tions and NFPA 58 for liquid propane applications.
Once the generator is installed, verify that the
fuel pressure NEVER drops below four (4) inches
water column for natural gas or 10 inches water
column for liquid propane.
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 install
ing 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 fitting.
All installed gaseous fuel piping must be purged and
leak tested prior to initial start-up in accordance with
local codes, standards and regulations.
FUEL CONSUMPTION
The fuel consumption rates are listed in the
SPECIFICATIONS section at the front of this manual.
BTU FLOW REQUIREMENTS - NATURAL GAS:
BTU flow required for each unit based on 1000 BTU
the slightest spark can ignite such fuels and
cause an explosion. No leakage of fuel is permitted. Natural gas, which is lighter than air,
tends to collect in high areas. LP gas is heavi-
-
-
-
-
er than air and tends to settle in low areas.
NOTE: A minimum of one approved manual shutoff valve must be installed in the gaseous fuel
supply line. The valve must be easily accessible.
Local codes determine the proper location.
RECONFIGURING THE FUEL SYSTEM
7 KW, 410CC ENGINE:
To reconfigure the fuel system from NG to LP, follow
these steps (Figure 1):
NOTE: The primary regulator for the propane sup
ply is NOT INCLUDED with the generator. A fuel
pressure of 10 to 12 inches of water column (0.36
to 0.43 psi) to the fuel inlet of the generator must
be supplied.
1. Turn off the main gas supply (if connected).
2. Open the roof and remove the door.
3. Remove the battery (if installed).
4. Disconnect Wire 0 and Wire 14 from the gas solenoid on
top of the demand regulator.
5. Remove the carburetor fuel hose from the outlet port of
the demand regulator.
6. Remove the demand regulator by removing the fastener
that retains the regulator mounting bracket.
-
Page 14
GENERAL INFORMATION
FUEL SELECTION
LEVER -
“IN” POSITION FOR
NATURAL GAS
FUEL SELECTION
LEVER -
“OUT” POSITION FOR
LIQUID PROPANE
(VAPOR) FUEL
PART 1
SECTION 1.3
PREPARATION BEFORE USE
7. Remove the square headed steel pipe plug from outlet port #1 and the brass hose barb fitting from outlet
port #2.
8. Refit the brass hose barb fitting to outlet port #1 and the
square headed steel pipe plug to outlet port #2.
PIPE
HOSE & PLUG
SWITCHED SIDES
LP FUEL SYSTEM
PRESSURE
TAP
FUEL HOSE
BRASS HOSE
FITTING
OUTLET
PORT
FUEL JET
FUEL HOSE
BRASS HOSE
FITTING
ADJUSTMENT
SCREW
PLUG
NG FUEL SYSTEM
12.Check for gas leakage at the pipe plug, hose connection
and fittings.
10, 13 AND 16 KW, V-TWIN ENGINES:
To reconfigure the fuel system from NG to LP, follow
these steps:
NOTE: The primary regulator for the propane sup
ply is NOT INCLUDED with the generator. A fuel
pressure of 10 to 12 inches of water column (0.36
to 0.43 psi) to the fuel inlet of the generator must
be supplied.
-
3/4” HOLE
NOTE: Use an approved pipe sealant or joint com
pound on all threaded fittings to reduce the possibility of leakage.
9. Reverse procedure Steps 1-6 to reinstall demand
regulator.
10.Take the plastic plug supplied in the poly-bag with the
generator and press it into the 3/4” hole on the bottom
of the air cleaner base (Figure 2).
11.Reverse the procedure to convert back to natural gas.
Figure 1. Demand Regulator
Figure 2. Demand Regulator
AIR
CLEANER
Figure 3. 10 kW, GT-530 (Inlet Hose Slid Back)
-
Figure 4. 10 kW, GT-530 (Inlet Hose Slid Back)
1. Open the roof.
2. For 10 kW units: Loosen clamp and slide back the
air inlet hose.
• Slide fuel selector on carburetor out towards the
back of the enclosure (Figures 3 and 4).
• Return the inlet hose and tighten clamp securely.
For 13 and 16 kW units: remove the air cleaner
cover.
Page 15
SECTION 1.3
PREPARATION BEFORE USE
PART 1
GENERAL INFORMATION
• Slide the selector lever out towards the back of the
enclosure (Figures 5 and 6).
• Return the air cleaner cover and tighten the two
thumb screws.
3. Close the roof.
4. Reverse the procedure to convert back to natural gas.
FUEL SELECTION
LEVER -
“IN” POSITION FOR
NATURAL GAS
Figure 5. 13/16 kW, GT-990 (Airbox Cover Removed)
ENGINE OIL RECOMMENDATIONS
The primary recommended oil for units with aircooled, single cylinder or V-Twin engines is synthetic
oil. Synthetic oil provides easier starts in cold weather
and maximum engine protection in hot weather. Use
high quality detergent oil that meets or exceeds API
(American Petroleum Institute) Service class SG, SH,
or SJ requirements for gasoline engines. The following chart lists recommended viscosity ranges for the
lowest anticipated ambient temperatures.
Engine crankcase oil capacities for the engines cov
ered in this manual can be found in the specifications
section at the beginning of the book.
Lowest Anticipated
Ambient Temperature
Above 60° F (16° C)Use SAE 30 oil
20° to 59° F (-7° to 15° C)Use SAE 10W-30 oil
Below 20° F (-7° C)SAE 5W-20/5W-30
For all seasonsUse SAE 5W-30 Synthetic oil
Oil Grade (Recommended)
-
FUEL SELECTION
LEVER -
“OUT” POSITION FOR
LIQUID PROPANE
(VAPOR) FUEL
Figure 6. 13/16 kW, GT-990 (Airbox Cover Removed)
Page 16
GENERAL INFORMATION
PART 1
SECTION 1.4
TESTING, CLEANING AND DRYING
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
“Hertz” 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 1) 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 VOLTAGE
An accurate AC voltmeter or a VOM may be used to
read the generator's AC output voltage. The following
apply:
1. Always read the generator's AC output voltage only at
the unit's rated operating speed and AC frequency.
2. The generator's Voltage Regulator can be adjusted for
correct output voltage only while the unit is operating at
its correct rated speed and frequency.
3. Only an AC voltmeter may be used to measure AC
voltage. DO NOT USE A DC VOLTMETER FOR THIS
PURPOSE.
DANGER!: GENERATORS PRODUCE HIGH
AND DANGEROUS VOLTAGES. CONTACT
WITH HIGH VOLTAGE TERMINALS WILL
RESULT IN DANGEROUS AND POSSIBLY
LETHAL ELECTRICAL SHOCK.
MEASURING DC VOLTAGE
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 polar-
ity 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 1. 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 cur-
rent 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 Rotor must run at 1800
rpm to deliver 60 Hertz.
Page 17
SECTION 1.4
TESTING, CLEANING AND DRYING
PART 1
GENERAL INFORMATION
Correct engine and Rotor speed is maintained by an
engine speed governor. For models rated 60 Hertz,
the governor is generally set to maintain a no-load frequency of about 62 Hertz with a corresponding output
voltage of about 124 volts AC line-to-neutral. Engine
speed and frequency at no-load are set slightly high
to prevent excessive rpm and frequency droop under
heavy electrical loading.
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 mea
sured safely and easily. A line-splitter can be used
to measure current in a cord without separating the
conductors.
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.
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 mea
sured.
In Figure 4 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
-
Figure 2. Clamp-On Ammeter
BATTERY
+-
Figure 4. A VOM as an In-line meter
RELAY
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.
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 condi
tions can be detected using a VOM:
• A “short-to-ground” condition in any Stator or Rotor
winding.
• Shorting together of any two parallel Stator wind
ings.
• Shorting together of any two isolated Stator wind
ings.
• An open condition in any Stator or Rotor winding.
-
-
-
Figure 3. A Line-Splitter
Page 18
GENERAL INFORMATION
PART 1
SECTION 1.4
TESTING, CLEANING AND DRYING
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 on a VOM.
Continuity is a closed condition between two electrical
points, which would be indicated as very low resistance 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 six thousand million billion electrons per second.
With alternating current (AC), the electrons flow first
in one direction, then reverse and move in the oppo
site 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 EMF that will cause a current of 1 ampere to flow
through 1 ohm of resistance.
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 electromotive force (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
-
AMPERE - Unit measuring rate of
Figure 5. Electrical Units
current flow (number of electrons
past a given point)
VOLT - Unit measuring force or
difference in potential
causing current flow
or opposition to flow
+
Figure 6. Ohm's Law
If AMPERES is unknown while VOLTS and OHMS are
known, use the following formula:
=
AMPERES
VOLTS
OHMS
VOLTS
Page 19
AMPERES =
If VOLTS is unknown while AMPERES and OHMS are
known, use the following formula:
VOLTS = AMPERES x OHMS
If OHMS is unknown but VOLTS and AMPERES are
known, use the following:
OHMS
SECTION 1.4
TESTING, CLEANING AND DRYING
PART 1
GENERAL INFORMATION
VISUAL INSPECTION
When it becomes necessary to test or troubleshoot a
generator, it is a good practice to complete a thorough
visual inspection. Remove the access covers and look
closely for any obvious problems. Look for the following:
• Burned or broken wires, broken wire connectors,
MINIMUM INSULATION
RESISTANCE=
(in “Megohms”)
damaged mounting brackets, etc.
• Loose or frayed wiring insulation, loose or dirty con
nections.
• Check that all wiring is well clear of rotating parts.
• Verify that the Generator properly connected for the
correct rated voltage. This is especially important on
new installations. See Section 1.2, “AC Connection
Systems”.
• Look for foreign objects, loose nuts, bolts and other
fasteners.
• Clean the area around the Generator. Clear away
paper, leaves, snow, and other objects that might
blow against the generator and obstruct its air
openings.
GENERATOR RATED VOLTS
__________________________
1000
+1
INSULATION RESISTANCE
Use a megger power setting of 500 volts. Connect
one megger test lead to the junction of all stator
leads, the other test lead to frame ground on the stator can. Read the number of megohms on the meter.
The MINIMUM acceptable megger reading for stators
may be calculated using the following formula:
EXAMPLE: Generator is rated at 120 volts AC.
Divide “120” by “1000” to obtain “0.12”. Then add
“1” to obtain “1.12” megohms. Minimum Insulation
resistance for a 120 VAC stator is 1.12 megohms.
If the stator insulation resistance is less than the cal
culated minimum resistance, clean and dry the stator.
Then, repeat the test. If resistance is still low, replace
the stator.
Use the Megger to test for shorts between isolated
windings as outlined “Stator Insulation Tests”.
Also test between parallel windings. See “Test
Between Windings” on next page.
TESTING ROTOR INSULATION:
Apply a voltage of 500 volts across the rotor posi-
tive (+) slip ring (nearest the rotor bearing), and
a clean frame ground (i.e. the rotor shaft). DO
NOT EXCEED 500 VOLTS AND DO NOT APPLY
VOLTAGE LONGER THAN 1 SECOND. FOLLOW
THE MEGGER MANUFACTURER’S INSTRUCTIONS
CAREFULLY.
ROTOR MINIMUM INSULATION RESISTANCE:
1.5 megohms
-
The insulation resistance of stator and rotor windings
is a measurement of the integrity of the insulating
materials that separate the electrical windings from
the generator steel core. This resistance can degrade
over time or due to such contaminants as dust, dirt,
oil, grease and especially moisture. In most cases,
failures of stator and rotor windings is due to a breakdown in the insulation. And, in many cases, a low insulation resistance is caused by moisture that collects
while the generator is shut down. When problems are
caused by moisture buildup on the windings, they can
usually be corrected by drying the windings. Cleaning
and drying the windings can usually eliminate dirt and
moisture built up in the generator windings.
THE MEGOHMMETER
GENERAL:
A megohmmeter, often called a “megger”, consists of
a meter calibrated in megohms and a power supply.
Use a power supply of 500 volts when testing stators
or rotors. DO NOT APPLY VOLTAGE LONGER THAN
ONE (1) SECOND.
TESTING STATOR INSULATION:
All parts that might be damaged by the high meg-
ger voltages must be disconnected before testing.
Isolate all stator leads (Figure 8) and connect all of
the stator leads together. FOLLOW THE MEGGER
MANUFACTURER’S INSTRUCTIONS CAREFULLY.
Page 20
CAUTION: Before attempting to measure
HI-POT TESTER:
A “Hi-Pot” tester is shown in Figure 7. The model
shown is only one of many that are commercially
available. The tester shown is equipped with a voltage
Insulation resistance, first disconnect and
Isolate all leads of the winding to be tested.
Electronic components, diodes, surge protectors, relays, voltage regulators, etc., can be
destroyed if subjected to high megger voltages.
Figure 7. One Type of Hi-Pot Tester
GENERAL INFORMATION
PART 1
SECTION 1.4
TESTING, CLEANING AND DRYING
selector switch that permits the power supply voltage
to be selected. It also mounts a breakdown lamp that
will illuminate to indicate an insulation breakdown during the test.
STATOR INSULATION RESISTANCE TEST
GENERAL:
Units with air-cooled engines are equipped with (a)
dual stator AC power windings, (b) an excitation
or DPE winding, and (c) a battery charge winding.
Insulation tests of the stator consist of (a) testing all
windings to ground, (b) testing between isolated windings, and (c) testing between parallel windings. Figure
8 is a pictorial representation of the various stator
leads on units with air-cooled engine.
TESTING ALL STATOR WINDINGS TO GROUND:
1. Disconnect stator output leads 11 and 44 from the generator main line circuit breaker.
2. Remove stator output leads 22 and 33 from the neutral
connection and separate the two leads.
3. Disconnect C2 Connector from the side of the control
panel. The C2 Connector is the closest to the back
panel (see Figure 9, Section 6.1).
c.Turn the tester switch ON and observe the
breakdown lamp on tester. DO NOT APPLY
VOLTAGE LONGER THAN 1 SECOND. After
one (1) second, turn the tester switch OFF.
If the breakdown lamp comes on during the one-sec
ond test, the stator should be cleaned and dried. After
cleaning and drying, repeat the insulation test. If, after
cleaning and drying, the stator fails the second test,
the stator assembly should be replaced.
6. Now proceed to the C2 Connector. Each winding will be
individually tested for a short to ground. Insert a large
paper clip (or similar item) into the C2 Connector at the
following pin locations:
Pin
Location
177Battery Charge
266Battery Charge
322Sense Lead Power
411Sense Lead Power
56Excitation
62Excitation
70Ground
84Positive to Brush
Wire
Number
Winding
-
2
6
11P
11S
22P
22S
33
44
66
77
Figure 8. Stator Winding Leads
4. Connect the terminal ends of Wires 11, 22, 33 and 44
together. Make sure the wire ends are not touching any
part of the generator frame or any terminal.
5. Connect the red test probe of the Hi-Pot tester to the
joined terminal ends of stator leads 11, 22, 33 and 44.
Connect the black tester lead to a clean frame ground
on the stator can. With tester leads connected in this
manner, proceed as follows:
a.Turn the Hi-Pot tester switch OFF.
b.Plug the tester cord into a 120 volt AC wall
socket and set its voltage selector switch to
“1500 volts”.
Next refer to Steps 5a through 5c of the Hi-Pot procedure.
Example: Insert paper clip into Pin 1, Hi-Pot from
Pin 1 (Wire 77) to ground. Proceed to Pin 2, Pin 3,
etc. through Pin 8.
5
6
7
8
Figure 9. C2 Connector Pin Location Numbers
(Female Side)
TEST BETWEEN WINDINGS:
1
2
3
4
1. Insert a large paper clip into Pin Location 1 (Wire 77).
Connect the red tester probe to the paper clip. Connect
the black tester probe to Stator Lead 11. Refer to Steps
5a through 5c of “TESTING ALL STATOR WINDINGS
TO GROUND” on previous page.
2. Repeat Step 1 at Pin Location 5 (Wire 6) and Stator
Lead 11.
3. Connect the red test probe to Stator Lead 33. Connect
the black test probe to Stator Lead 11. Refer to Steps 5a
through 5c of “TESTING ALL STATOR WINDINGS TO
GROUND” on previous page.
Page 21
SECTION 1.4
TESTING, CLEANING AND DRYING
4. Insert a large paper clip into Pin Location No. 1 (Wire
77). Connect the red tester probe to the paper clip.
Connect the black tester probe to Stator Lead 33. Refer
to Steps 5a through 5c of “TESTING ALL STATOR
WINDINGS TO GROUND” on the previous page.
5. Repeat Step 4 at Pin Location 3 (Wire 6) and Stator
Lead 33.
For the following Step (7) an additional large paper
clip (or similar item) will be needed:
7. Insert a large paper clip into Pin Location 1 (Wire 77).
Connect the red tester probe to the paper clip. Insert the
additional large paper clip into Pin Location 5 (Wire 6).
Connect the black tester probe to this paper clip. Refer
to Steps 5a through 5c of “TESTING ALL STATOR
WINDINGS TO GROUND” on the previous page.
PART 1
POSITIVE (+)
TEST LEAD
Figure 10. Testing Rotor Insulation
GENERAL INFORMATION
ROTOR INSULATION RESISTANCE TEST
Before attempting to test rotor insulation, the brush
holder must be completely removed. The rotor must
be completely isolated from other components before
starting the test. Attach all leads of all stator windings
to ground.
1. Connect the red tester lead to the positive (+) slip ring
(nearest the rotor bearing).
2. Connect the black tester probe to a clean frame ground,
such as a clean metal part of the rotor shaft.
3. Turn the tester switch OFF.
4. Plug the tester into a 120 volts AC wall socket and set
the voltage switch to “1500 volts”.
5. Turn the tester switch “On” and make sure the pilot light
has turned on.
6. Observe the breakdown lamp, then turn the tester switch
OFF. DO NOT APPLY VOLTAGE LONGER THAN ONE
(1) SECOND.
If the breakdown lamp came on during the one (1)
second test, cleaning and drying of the rotor may be
necessary. After cleaning and drying, repeat the insulation breakdown test. If breakdown lamp comes on
during the second test, replace the rotor assembly.
CLEANING THE GENERATOR
Caked or greasy dirt may be loosened with a soft
brush or a damp cloth. A vacuum system may be
used to clean up loosened dirt. Dust and dirt may
also be removed using dry, low-pressure air (25 psi
maximum).
CAUTION: Do not use sprayed water to clean
the generator. Some of the water will be
retained on generator windings and terminals,
and may cause very serious problems.
DRYING THE GENERATOR
To dry a generator, proceed as follows:
1. Open the generator main circuit breaker. NO
ELECTRICAL LOADS MUST BE APPLIED TO THE
GENERATOR WHILE DRYING.
2. Disconnect all Wires 4 from the voltage regulator.
3. Provide an external source to blow warm, dry air through
the generator interior (around the rotor and stator windings. DO NOT EXCEED 185° F. (85° C.).
4. Start the generator and let it run for 2 or 3 hours.
5. Shut the generator down and repeat the stator and rotor
insulation resistance tests.
Page 22
GENERAL INFORMATION
LOW OIL SWITCHHIGH TEMP SWITCH
PART 1
SECTION 1.5
ENGINE-GENERATOR PROTECTIVE DEVICES
GENERAL
Standby electric power generators will often run
unattended for long periods of time. Such operating
parameters as (a) battery voltage, (b) engine oil pressure, (c) engine temperature, (d) engine operating
speed, and (e) engine cranking and startup are not
monitored by an operator during automatic operation.
Because engine operation will not be monitored, the
use of engine protective safety devices is required to
prevent engine damage in the event of a problem.
Prepackaged generator engines mount several engine
protective devices. These devices work in conjunction
with a circuit board, to protect the engine against
such operating faults as (a) low battery, (b) low engine
oil pressure, (c) high temperature, (d) overspeed, and
(e) overcrank. On occurrence of any one or more of
those operating faults, circuit board action will effect
an engine shutdown.
LOW BATTERY
The microprocessor will continually monitor the battery voltage and turn on the Low Battery LED if the
battery voltage falls below 11.0 volts for one (1) minute. No other action is taken on a low battery condition. Low battery voltage is a non-latching alarm
which will automatically clear if the battery voltage
rises above 11.0 volts. Battery voltage is NOT monitored during the crank cycle.
OVERSPEED SHUTDOWN
During engine cranking and operation, the circuit
board receives AC voltage and frequency signals from
the ignition magneto, via Wire 18. Should the speed
exceed approximately 72 Hz (4320 rpm), circuit board
action will de-energize a “run relay” (mounted on the
circuit board). The relay’s contacts will open, to terminate engine ignition and close a fuel shutoff solenoid.
The engine will then shut down. This feature protects
the engine-generator against damaging overspeeds.
NOTE: The circuit board also uses rpm sensing to
terminate engine cranking.
RPM SENSOR FAILURE
During cranking, if the board does not see a valid
RPM signal within three (3) seconds, it will shut down
and latch out on RPM sensor loss.
During running, if the RPM signal is lost for one full
second the board will shut down the engine, wait 15
seconds, then re-crank the engine.
• If an RPM signal is not detected within the first three
(3) seconds of cranking, the control board will shut
the engine down and latch out on RPM sensor loss.
• If the RPM signal is detected the engine will start
and run normally. If the RPM signal is subsequently
lost again, the control board will try one more recrank attempt before latching out and flashing the
overspeed LED.
LOW OIL PRESSURE SHUTDOWN
See Figure 1. An oil pressure switch is mounted on
the engine oil filter adapter. This switch has normally
closed contacts that are held open by engine oil pressure during cranking and startup. Should oil pressure
drop below approximately 8 psi, the switch contacts
will close. On closure of the switch contacts, a Wire
86 circuit from the circuit board will be connected to
ground. Circuit board action will then de-energize a
“run relay” (on the circuit board). The run relay’s normally open contacts will then open and a 12 volts DC
power supply to a Wire 14 circuit will then be terminated. This will result in closure of a fuel shutoff solenoid
and loss of engine ignition.
HIGH TEMPERATURE SWITCH
This switch’s contacts (Figure 1) close if the temperature should exceed approximately 140° C (284° F),
initiating an engine shutdown. The generator will automatically restart and the LED on the generator control
panel will reset once the temperature has returned to
a safe operating level.
Figure 1. Engine Protective Switches on an
Air-Cooled Engine
Page 23
SECTION 1.5
ENGINE-GENERATOR PROTECTIVE DEVICES
OVERCRANK SHUTDOWN
This feature prevents the generator from damaging
itself when it continually attempts to start and another
problem, such as no fuel supply, prevents it from starting. The unit will crank and rest for a preset time limit.
Then, it will stop cranking, and the LED on the generator control panel will light indicating an overcrank
failure. The AUTO/OFF/MANUAL switch will need to
be set to OFF and then back to AUTO to reset the
generator control board.
NOTE: If the fault is not repaired, the overcrank
feature will continue to activate.
APPROXIMATE CRANK CYCLE TIMES:
7 KW UNITS:
15 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
If the unit fails to start, the overcrank alarm LED will
be illuminated.
PART 1
GENERAL INFORMATION
10 KW, 13 KW AND 16 KW UNITS:
16 seconds ON
7 seconds OFF
16 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
7 seconds ON
7 seconds OFF
If the unit fails to start, the overcrank alarm LED will
be illuminated.
Page 24
GENERAL INFORMATION
PART 1
SECTION 1.6
OPERATING INSTRUCTIONS
CONTROL PANEL
GENERAL:
See Figure 1 for control panel configurations.
CONTROL AND INFORMATION CENTER
SYSTEM SET
LOW BATTERY
OFF
AUTO.MAN.
SYSTEM FUSE
15A
ASSY: 0F8418/0F8419
SET
EXERCISE
TIME
Figure 1. Control Panel
AUTO-OFF-MANUAL SWITCH:
Use this switch to (a) select fully automatic operation,
(b) to crank and start the engine manually, and (c) to
shut the unit down or to prevent automatic startup.
1. AUTO position:
a.Select AUTO for fully automatic operation.
b.When AUTO is selected, circuit board will moni-
tor utility power source voltage.
c. Should utility voltage drop below a preset level
and remain at such a low level for a preset time,
circuit board action will initiate engine cranking
and startup.
d.Following engine startup, circuit board action
will initiate transfer of electrical loads to the
“Standby” source side.
e.On restoration of utility source voltage above
a preset level, circuit board action will initiate
retransfer back to the “Utility Source” side.
f. Following retransfer, circuit board will shut the
engine down and will then continue to monitor
utility source voltage.
2. OFF Position:
a.Set the switch to OFF to stop an operating
engine.
b.To prevent an automatic startup from occurring,
set the switch to OFF.
3. MANUAL Position:
a.Set switch to MANUAL to crank and start unit
manually.
b.Engine will crank cyclically and start (same as
automatic startup, but without transfer). The unit
will transfer if utility voltage is not available.
DANGER: WHEN THE GENERATOR IS
INSTALLED IN CONJUNCTION WITH AN
AUTOMATIC TRANSFER SWITCH, ENGINE
CRANKING AND STARTUP CAN OCCUR AT
LOW OIL
HIGH TEMP
OVER SPEED
NO RPM SENSE IF FLASHING
OVER CRANK
FLASHING GREEN LED=
NO UTILITY SENSE
5 FLASHING RED LEDS=
EXERCISER NOT SET
ANY TIME WITHOUT WARNING (PROVIDING
THE AUTO-OFF-MANUAL SWITCH IS SET TO
AUTO). TO PREVENT AUTOMATIC STARTUP
AND POSSIBLE INJURY THAT MIGHT BE
CAUSED BY SUCH STARTUP, ALWAYS SET
THE AUTO-OFF-MANUAL SWITCH TO ITS
OFF POSITION BEFORE WORKING ON OR
AROUND THIS EQUIPMENT.
15 AMP FUSE:
This fuse protects the DC control circuit (including the
circuit board) against overload. If the fuse element
has melted open due to an overload, engine cranking
or running will not be possible. Should fuse replacement become necessary, use only an identical 15
amp replacement fuse.
THE SET EXERCISE SWITCH:
This generator is equipped with an exercise timer.
Once it is set, the generator will start and exercise
once every seven days, on the day of the week and at
the time of day the following sequence is completed.
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 power is lost.
A switch on the control panel (see Figure 1) per
mits selection of the day and time for the system to
exercise. At the chosen time, perform the following
sequence to select the desired day and time of day
the system will exercise. Remember seasonal time
changes affect the exercise time settings.
1. Verify that the AUTO/OFF/MANUAL switch is set to
AUTO.
2. Press and hold the "Set Exercise Time" switch for sev-
eral seconds, then release. All the red LED's will flash
for approximately 10 seconds and then stop.
3. Once the red LED's stop flashing, the generator will start
and run for approximately 12 minutes and then shut
down. The exerciser is now set to run at this time of day
each week.
Example: If the "Set Exercise Time" switch is pressed
on Saturday afternoon at 2:00 p.m., the generator will
start and exercise for approximately 12 minutes every
Saturday at 2:00 p.m..
NOTE: The exerciser will only work in the AUTO
mode and will not work unless this procedure
is performed. The exerciser will need to be reset
every time the 12 volt battery is disconnected
and then reconnected, and when the 15A fuse is
removed.
The 16 kW unit has a low speed exercise option. Dip
switch 1 on the control board is factory set to OFF.
This allows the engine to run at a slower speed during
weekly exercise periods for quieter operation. If this
Dip switch is set to ON, the generator will exercise at
it's normal speed.
-
Page 25
SECTION 1.6
OPERATING INSTRUCTIONS
PART 1
GENERAL INFORMATION
This DIP switch position is only read at board power
up. If the DIP switch position is changed, power to the
board must be cycled for the micro controller to recognize the new DIP switch position.
Low speed exercise will be handled as follows:
1. The standard start sequence will be initiated.
2. The unit will run at 2,400 RPM.
3. If utility is lost during exercise, the controller will do the
following:
• Wait 10 seconds for utility to return.
• If utility returns within 10 seconds, continue to exer
cise at 2,400 RPM.
• If utility is still lost after 10 seconds, run the engine
up to 3600 RPM and transfer the load. At this time
the controller will exit the exercise routine and
assume full automatic operation.
PROTECTION SYSTEMS:
Unlike an automobile engine, the generator may have
to run for long periods of time with no operator present to monitor engine conditions. For that reason, the
engine is equipped with the following systems that
protect it against potentially damaging conditions:
• Low Battery
• Low Oil Pressure Sensor
• High Temperature Sensor
• Overcrank
• Overspeed
• No RPM Sense
There are LED readouts on the control panel to notify
you that one of these faults has occurred. There is
also a “System Set” LED that is lit when all of the fol
lowing conditions are true:
1. The AUTO-OFF-MANUAL switch is set to the AUTO position.
2. The NOT IN AUTO dip switch is set to the OFF position
on the control board.
3. No alarms are present.
To select automatic operation when a prepackaged
transfer switch is installed along with a prepackaged
home standby generator, proceed as follows:
1. Check that the prepackaged transfer switch main contacts are at their UTILITY position, i.e., the load is
connected to the power supply. If necessary, manually actuate the switch main contacts to their UTILITY
source side. See Part 5 of this manual, as appropriate,
for instructions.
2. Check that utility source voltage is available to transfer
-
switch terminal lugs N1 and N2 (2-pole, 1-phase transfer switches).
3. Set the generator AUTO-OFF-MANUAL switch to its
AUTO position.
4. Actuate the generator main line circuit breaker to its “On”
or “Closed” position. With the preceding Steps 1 through
4 completed, a dropout in utility supply voltage below a
preset level will result in automatic generator cranking
and start-up. Following startup, the prepackaged transfer
switch will be actuated to its “Standby” source side, i.e.,
loads powered by the standby generator.
MANUAL TRANSFER TO “STANDBY” AND
MANUAL STARTUP
To transfer electrical loads to the “Standby” (generator) source and start the generator manually, proceed
as follows:
1. On the generator panel, set the AUTO-OFF-MANUAL
-
switch to OFF.
2. On the generator, set the main line circuit breaker to it’s
OFF or “Open” position.
3. Turn OFF the power supply to the transfer switch, using
whatever means provided (such as a utility source line
circuit breaker).
TO SELECT AUTOMATIC OPERATION
The following procedure applies only to those installations in which the air-cooled, prepackaged automatic
standby generator is installed in conjunction with a
prepackaged transfer switch. Prepackaged transfer
switches do not have an intelligence circuit of their
own. Automatic operation on prepackaged transfer
switch and generator combinations is controlled by
circuit board action.
Page 26
4. Manually actuate the transfer switch main contacts to
their “Standby” position, i.e., loads connected to the
“Standby” power source side.
NOTE: For instructions on manual operation of
prepackaged transfer switches, see Part 5.
5. On the generator panel, set the AUTO-OFF-MANUAL
switch to MANUAL. The engine should crank and start.
6. Let the engine warm up and stabilize for a minute or two
at no-load.
7. Set the generator main line circuit breaker to its “On” or
“Closed” position. The generator now powers the electrical loads.
GENERAL INFORMATION
PART 1
MANUAL SHUTDOWN AND RETRANSFER
BACK TO “UTILITY”
To shut the generator down and retransfer electrical
loads back to the UTILITY position, proceed as follows:
1. Set the generator main line circuit breaker to its OFF or
“Open” position.
2. Let the generator run at no-load for a few minutes, to cool.
3. Set the generator AUTO-OFF-MANUAL switch to OFF.
Wait for the engine to come to a complete stop.
4. Turn off the utility power supply to the transfer switch
using whatever means provided (such as a utility source
main line circuit breaker)
5. Manually actuate the prepackaged transfer switch to its
UTILITY source side, i.e., load connected to the utility
source.
6. Turn on the utility power supply to the transfer switch,
using whatever means provided.
SECTION 1.6
OPERATING INSTRUCTIONS
7. Set the generator AUTO-OFF-MANUAL switch to AUTO.
Page 27
SECTION 1.7
AUTOMATIC OPERATING PARAMETERS
PART 1
GENERAL INFORMATION
INTRODUCTION
When the prepackaged generator is installed in
conjunction with a prepackaged transfer switch,
either manual or automatic operation is possible.
Manual transfer and engine startup, as well as
manual shutdown and retransfer are covered in
Section 1.6. Selection of fully automatic operation
is also discussed in that section. This section will
provide a step-by-step description of the sequence
of events that will occur during automatic operation
of the system.
AUTOMATIC OPERATING SEQUENCES
The generator’s control panel houses a control logic
circuit board. This board constantly monitors utility power source voltage. Should that voltage drop
below a preset level, circuit board action will signal
the engine to crank and start. After the engine starts,
the circuit board signals the transfer switch to activate
and connect load circuits to the standby power supply
(load terminal lugs T1/T2 connect to terminal lugs E1/
E2). Refer to the Electrical Data section.
The generator must run at 50 Hz or greater for the
transfer output to be activated. Once activated, it will
remain active even if the frequency dips below 50 Hz.
Upon restoration of utility source voltage above a
preset level, generator circuit board action signals the
transfer switch to transfer loads back to that power
supply. After retransfer, the engine is signalled to shut
down.
The actual sequence of operation is controlled by
sensors and timers on a control logic circuit board, as
follows:
A. Utility Voltage Dropout Sensor
• This sensor monitors utility source voltage.
• If utility source voltage drops below about 65 percent
of the nominal supply voltage, the sensor energizes a
10 second timer.
• Once the timer has expired, the engine will crank and
start if utility is still low.
B. Engine Warm-up Time Delay
• This mechanism lets the engine warm up for about
five (5) seconds before the load is transferred to the
standby source.
C. Standby Voltage Sensor
• This sensor monitors generator AC output voltage.
When the voltage has reached 50 percent of the
nominal rated voltage, transfer to standby can occur.
D. Utility Voltage Pickup Sensor
• This sensor monitors utility power supply voltage.
When that voltage is restored above 75 percent of the
nominal source voltage, a retransfer time delay starts
timing.
E. Retransfer Time Delay
• This timer runs for about 15 seconds.
• At end of a 15-second delay, circuit board action deenergizes transfer relay in the transfer switch if utility
is still present.
• Retransfer to utility power source then occurs.
F. Engine Cool-down Timer
Page 28
• When the load is transferred back to utility power
source, the engine cool-down timer starts timing.
• The timer will run for about one minute, and the gen
erator will then shut down.
-
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