Kohler Decision-Maker MPAC 750 Instruction Manual

Automatic Transfer Switches
Controls:
Decision-MakerrMPAC 750
Transfer Switch Model:
KSS
TP-6865 4/14a
Operation

Table of Contents
TP-6865 4/14 Table of Contents 3
Safety Precautions and Instructions 5.........................................................
Introduction 7...............................................................................
List of Related Materials 7......................................................
Service Assistance 8.........................................................................
Section 1 Operation 9........................................................................
1.1 Introduction 9...........................................................
1.2 Source Names 9........................................................
1.3 User Interface Panel 9...................................................
1.3.1 Pushbuttons 9..................................................
1.3.2 LED Indicators 10................................................
1.4 Test 10..................................................................
1.4.1 Unloaded System Test 10.........................................
1.4.2 Loaded System Test 10...........................................
1.5 Automatic Operation Test 11...............................................
1.6 Exercise 12..............................................................
1.6.1 Exercise Schedule 12.............................................
1.6.2 Unloaded Exercise 12.............................................
1.6.3 Loaded Exercise 12...............................................
1.6.4 Stopping an Exercise 12...........................................
1.6.5 Optional Programmable Exerciser 12...............................
1.7 Warnings and Faults 13...................................................
1.7.1 Fault Reset 14...................................................
1.8 Controller Reset 14.......................................................
1.8.1 Reboot 14.......................................................
1.8.2 Reset to Default Settings 14.......................................
Section 2 Sequence of Operation 15...........................................................
2.1 Controller Power--up/Reset 15.............................................
2.2 Sequence of Operation 15.................................................
2.2.1 Source N Loss and Return 15......................................
2.2.2 Exerciser Operation 15............................................
2.2.3 Test Sequence 16................................................
Section 3 Settings 17.........................................................................
3.1 Introduction 17...........................................................
3.2 System Setup 17.........................................................
3.3 System Parameters 17....................................................
3.3.1 Transition Type, Standard 17.......................................
3.3.2 Commit to Transfer: No 17.........................................
3.3.3 In-Phase Monitor 17..............................................
3.4 Voltage Pickup and Dropout Settings 18.....................................
3.5 Time Delays 18..........................................................
3.6 Programmable Inputs and Outputs 18.......................................
3.6.1 Input Functions 19................................................
3.6.2 Output Functions 19..............................................
3.7 Common Alarms 20.......................................................
3.8 Communications 20.......................................................
Section 4 Communications 21.................................................................
4.1 Introduction 21...........................................................
4.2 Connections 21..........................................................
4.2.1 USB Port SiteTech Connection 21..................................
4.2.2 Modbus Connection 22............................................
4.2.3 Ethernet Connection (Optional) 24..................................

Table of Contents, continued
TP-6865 4/14Table of Contents4
4.3 Communications Setup 26.................................................
4.3.1 Modbus Serial Communication Setup 26............................
4.3.2 Network Communication Setup 26..................................
4.3.3 Setup Using SiteTech 26..........................................
4.4 Parameter Files 29.......................................................
4.5 Controller Firmware Updates 29............................................
Section 5 Scheduled Maintenance 31..........................................................
5.1 Introduction 31...........................................................
5.2 Testing 32...............................................................
5.2.1 Weekly Generator Set Exercise 32..................................
5.2.2 Monthly Automatic Control System Test 32...........................
5.3 Inspection and Service 33.................................................
5.3.1 General Inspection 33.............................................
5.3.2 SPD Inspection 33................................................
5.3.3 Other Inspections and Service 33...................................
5.4 Service Schedule 34......................................................
Section 6 Accessories 35.....................................................................
6.1 Introduction 35...........................................................
6.2 Controller Disconnect Switch 35............................................
6.3 Ethernet Board 36........................................................
6.4 Programmable Exerciser 36...............................................
6.5 Heater 37...............................................................
6.6 Surge Protection (SPD) 38.................................................
6.6.1 SPD Status Indicators 40..........................................
6.6.2 SPD Remote Status Indicator 40...................................
6.6.3 SPD Replacement 40.............................................
6.7 User Interface Cover 41...................................................
Appendix A Abbreviations 43................................................................

TP-6865 4/14 5Safety Precautions and Instructions
Safety Precautions and Instructions
IMPORTANT SAFETY INSTRUCTIONS.
Electromechanical equipment,
including generator sets, transfer
switches, switchgear, and accessories,
can cause bodily harm and pose
life-threatening danger when
improperly installed, operated, or
maintained. To prevent accidents be
aware of potential dangers and act
safely. Read and follow all safety
precautions and instructions. SAVE
THESE INSTRUCTIONS.
This manual has several types of safety
precautions and instructions: Danger,
Warning, Caution, and Notice.
DANGER
Danger indicates the presence of a
hazard that will cause severe
personal injury, death,orsubstantial
property damage.
WARNING
Warning indicates the presence of a
hazard that can cause severe
personal injury, death, or substantial
property damage.
CAUTION
Caution indicates the presence of a
hazard that will or can cause minor
personal injury or property damage.
NOTICE
Notice communicates installation,
operation, or maintenance information
that is safety related but not hazard
related.
Safety decals affixed to the equipment
in prominent places alert the operator
or service technician to potential
hazards and explain how to act safely.
The decals are shown throughout this
publication to improve operator
recognition. Replace missing or
damaged decals.
Accidental Starting
Accidental starting.
Can cause severe injury or death.
Disconnect the battery cables before
working on the generator set.
Remove the negative (--) lead first
when disconnecting the battery.
Reconnect the negative (--) lead last
when reconnecting the battery.
WARNING
Disabling the generator set.
Accidental starting can cause
severe injury or death. Before
working on the generator set or
connected equipment, disable the
generator set as follows: (1) Move the
generator set master switch to the OFF
position. (2) Disconnect the power to
the battery charger. (3) Remove the
battery cables, negative (--) lead first.
Reconnect the negative (--) lead last
when reconnecting the battery. Follow
these precautions to prevent starting of
the generator set by an automatic
transfer switch, remote start/stop
switch, or engine start command from a
remote computer.
(Decision-Makerr3+ and 550
Generator Set Controllers)
Disabling the generator set.
Accidental starting can cause
severe injury or death. Before
working on the generator set or
equipment connected to the set,
disable the generator set as follows:
(1) Press the generator set off/reset
button to shut down the generator set.
(2) Disconnect the power to the battery
charger, if equipped. (3) Remove the
battery cables, negative (--) lead first.
Reconnect the negative (--) lead last
when reconnecting the battery. Follow
these precautions to prevent the
starting of the generator set by the
remote start/stop switch.
(Decision-Makerr3000 and 6000
Generator Set Controllers)
Hazardous Voltage/
Moving Parts
Hazardous voltage.
Will cause severe injury or death.
Disconnect all power sources before
opening the enclosure.
DANGER
Hazardous voltage.
Will cause severe injury or death.
Only authorized personnel should
open the enclosure.
DANGER
Hazardous voltage.
Will cause severe injury or death.
Disconnect all power sources before
servicing. Install the barrier after
adjustments, maintenance, or
servicing.
DANGER
Hazardous voltage.
Can cause severe injury or death.
Operate the generator set only when
all guards and electrical enclosures
areinplace.
Moving parts.
WARNING

TP-6865 4/146 Safety Precautions and Instructions
WARNING
Hazardous voltage.
Can cause severe injury or death.
Close and secure the enclosure door
before energizing the transfer switch.
Grounding electrical equipment.
Hazardous voltage can cause
severe injury or death. Electrocution
is possible whenever electricity is
present. Ensure you comply with all
applicable codes and standards.
Electrically ground the generator set,
transfer switch, and related equipment
and electrical circuits. Turn off the main
circuit breakers of all power sources
before servicing the equipment. Never
contact electrical leads or appliances
when standing in water or on wet
ground because these conditions
increase the risk of electrocution.
Short circuits. Hazardous
voltage/current can cause severe
injury or death. Short circuits can
cause bodily injury and/or equipment
damage.Do not contact electrical
connections with tools or jewelry while
making adjustments or repairs.
Remove all jewelry before servicing the
equipment.
Servicing the transfer switch.
Hazardous voltage can cause
severe injury or death. Deenergize all
power sources before servicing. Turn
off the main circuit breakers of all
transfer switch power sources and
disable all generator sets as follows:
(1) Move all generator set master
controller switches to the OFF position.
(2) Disconnect power to all battery
chargers. (3) Disconnect all battery
cables, negative (--) leads first.
Reconnect negative (--) leads last when
reconnecting the battery cables after
servicing. Follow these precautions to
prevent the starting of generator sets
by an automatic transfer switch, remote
start/stop switch, or engine start
command from a remote computer.
Before servicing any components
inside the enclosure: (1) Remove all
jewelry. (2) Stand on a dry, approved
electrically insulated mat. (3) Test
circuits with a voltmeter to verify that
they are deenergized.
Making line or auxiliary
connections. Hazardous voltage
can cause severe injury or death. To
prevent electrical shock deenergize the
normal power source before making
any line or auxiliary connections.
Servicing the transfer switch
controls and accessories within the
enclosure. Hazardous voltage can
cause severe injury or death.
Disconnect the transfer switch controls
at the inline connector to deenergize
the circuit boards and logic circuitry but
allow the transfer switch to continue to
supply power to the load. Disconnect
all power sources to accessories that
are mounted within the enclosure but
are not wired through the controls and
deenergized by inline connector
separation. Test circuits with a
voltmeter to verify that they are
deenergized before servicing.
Testing live electrical circuits.
Hazardous voltage or current can
cause severe injury or death. Have
trained and qualified personnel take
diagnostic measurements of live
circuits. Use adequately rated test
equipment with electrically insulated
probes and follow the instructions of the
test equipment manufacturer when
performing voltage tests. Observe the
following precautions when performing
voltage tests: (1) Remove all jewelry.
(2) Stand on a dry, approved electrically
insulated mat. (3) Do not touch the
enclosure or components inside the
enclosure. (4) Be prepared for the
system to operate automatically.
(600 volts and under)
Heavy Equipment
Unbalanced weight.
Improper lifting can cause severe
injury or death and equipment
damage.
Use adequate lifting capacity.
Never leave the transfer switch
standing upright unless it is securely
bolted in place or stabilized.
WARNING
Notice
NOTICE
Improper operator handle usage.
Use the manual operator handle on the
transfer switch for maintenance
purposes only. Return the transfer
switch to the normal position. Remove
the manual operator handle, if used,
and store it in the place provided on the
transfer switch when service is
completed.
NOTICE
Electrostatic discharge damage.
Electrostatic discharge (ESD)
damages electronic circuit boards.
Prevent electrostatic discharge
damage by wearing an approved
grounding wrist strap when handling
electronic circuit boards or integrated
circuits. An approved grounding wrist
strap provides a high resistance (about
1 megohm), not a direct short,to
ground.

TP-6865 4/14 7Introduction
Introduction
This manual provides operation instructions for Kohlerr
Decision-MakerrMPAC 750 automatic transfer switch
controls and related accessories.
Information in this publication represents data available
at the time of print. Kohler Co. reserves the right to
change this literature and the products represented
without notice and without any obligation or liability
whatsoever.
The equipment service requirements are very important
to safe and efficient operation. Inspect parts often and
perform required service at the prescribed intervals.
Obtain service from an authorized service distributor/
dealer to keep equipment in top condition.
Read this manual and carefully follow all procedures
and safety precautions to ensure proper equipment
operation and to avoid bodily injury. Read and follow the
Safety Precautions and Instructions section at the
beginning of this manual. Keep this manual with the
equipment for future reference.
List of Related Materials
A separate transfer switch installation manual provided
with the unit contains instructions for transfer switch
installation and manual operation procedures.
Literature Item Part Number
Specification Sheet, MPAC 750 Controller G11-126
Specification Sheet, Model KSS/KSP G11-130
Installation Manual, Model KSS/KSP TP-6834
Operation Manual, Modbus Protocol TP-6113

TP-6865 4/148 Service Assistance
Service Assistance
For professional advice on generator power
requirements and conscientious service, please contact
your nearest Kohler distributor or dealer.
DConsult the Yellow Pages under the heading
Generators—Electric.
DVisit the Kohler Power Systems website at
KOHLERPower.com.
DLook at the labels and stickers on your Kohler product
or review the appropriate literature or documents
included with the product.
DCall toll free in the US and Canada 1-800-544-2444.
DOutside the US and Canada, call the nearest regional
office.
Headquarters Europe, Middle East,Africa
(EMEA)
Kohler Power Systems Netherlands B.V.
Kristallaan 1
4761 ZC Zevenbergen
The Netherlands
Phone: [phone]
Fax: [phone]
Asia Pacific
Power Systems Asia Pacific Regional Office
Singapore, Republic of Singapore
Phone: [phone]
Fax: [phone]
China
North China Regional Office, Beijing
Phone: [phone]
(86) 10 6518 7951
(86) 10 6518 7952
Fax: [phone]
East China Regional Office, Shanghai
Phone: [phone]
Fax: [phone]
India, Bangladesh, Sri Lanka
India Regional Office
Bangalore, India
Phone: [phone]
(91) 80 3366231
Fax: [phone]
Japan, Korea
North Asia Regional Office
Tokyo, Japan
Phone: [phone]
Fax: [phone]
Latin America
Latin America Regional Office
Lakeland, Florida, USA
Phone: [phone]
Fax: [phone]

TP-6865 4/14 9Section 1 Operation
Section 1 Operation
1.1 Introduction
This section contains operation instructions, including:
DUser interface panel, with pushbuttons and LED
indicators
DWarnings and faults
DTest
DExercise
DController Reset
1.2 Source Names
Throughout this manual, the sources are referred to
using the following names:
DSource N
DSource E
DPreferred Source
DStandby Source
Source N is connected to the Normal side of the transfer
switch. Source E is connected to the Emergency side of
the transfer switch. In most applications, Source N is the
utility source, and Source E is the standby generator set.
The engine start contacts are associated with Source E.
The Preferred Source is the source that will be used if
both sources are available. With the MPAC 750
controller, the preferred source is Source N. The
standby source is Source E.
1.3 User Interface Panel
The user interface panel is located on the transfer switch
door. Figure 1-1 shows the user interface pushbuttons
and LED indicators.
1.3.1 Pushbuttons
The user interface panel has two pushbuttons:
DTest (see Section 1.4)
DExercise (see Section 1.6)
1. Source N Available LED
2. Source N Position LED
3. Source E Position LED
4. Source E Available LED
5. USB port location
6. System Alert LED
7. Not in Auto LED
8. Exercise button
9. Test button
GM85888
6
123 4
7
9
5
8
Figure 1-1 User Interface Panel

TP-6865 4/1410 Section 1 Operation
1.3.2 LED Indicators
LEDs on the user interface indicate contactor position,
source availability, faults, and other conditions. The
table in Figure 1-2 describes the functions of the LED
indicators. Source N is connected to the normal side of
the ATS and is typically the utility source. Source E is
connected to the emergency side of the ATS and is
typically the generator set.
The Source E Available and Source E Position LEDs
also indicate test and exercise runs as described in
Figure 1-3. See Sections 1.4 and 1.6 for more
information.
See Section 1.7 for more information about warnings
and faults.
Some programmable inputs will trigger the LEDs to light
or flash. See Section 3.6.
LED Indicator Condition
Source N Available,
Green
Source N is available.
Source E Available, Red Source E is available.
Position N, Green Contactor is in Normal position.
Position E, Red Contactor is in Emergency position.
System Alert, Red Fault. Identify and correct the cause
of the fault condition, then reset faults
at the controller. See Section 1.7.
Input active: Low Battery Voltage or
Remote Common Alarm. See
Section 3.6.
Not in Auto, Red ATS is not set for automatic
operation.
Flashes for manual transfer waiting.
Inhibit Transfer input is active. See
Section 3.6.
Figure 1-2 User Interface LED Indicators
Condition
Source E
Available (RED)
Source E
Position (RED)
Unloaded Test Flash 1sec/1sec OFF
Loaded Test Flash 1sec/1sec Flash 1sec/1sec
Unloaded Exercise Flash 0.5 sec/2 sec OFF
Loaded Exercise Flash 0.5 sec/2 sec Flash 0.5 sec/2 sec
Figure 1-3 Test and Exercise Indication
1.4 Test
Use the Test button to:
DStart and run the generator set (unloaded test).
DSimulate a Source N failure, resulting in a transfer to
Source E (loaded test).
If the emergency source is lost during a system test, the
test is terminated. If the contactor is in the standby
position, it transfers immediately to the preferred
position.
For remote test information, also see Section 3.6.1.
1.4.1 Unloaded System Test
Press and hold the Test button for 3--5 seconds to start
an unloaded test. The generator set will start without
waiting for the engine start time delay. The load is not
transferred to the generator set. The generator runs
until the test is ended.
During an unloaded test, the Source E available LED
flashes, 1 second on and 1 second off.
Press and hold the Test pushbutton for about 2 seconds
to end the test. Time delays will execute as programmed
when the test is ended. The Source E available LED
lights during the time delays. The generator set shuts
down.
If the normal source fails during the test, the contactor
transfers to the emergency source. The ATS then
monitors the sources and operates automatically when
the normal source returns.
1.4.2 Loaded System Test
A loaded test simulates a failure of source N. Press and
hold the Test button for 6 seconds or longer to start a
loaded test. The generator set will start without waiting
for the engine start time delay. The ATS then transfers
the load to the generator set.
Since the loaded test transfer will be between two live
sources, the in-phase monitor feature will be activated if
it is enabled.
During a loaded test, the Source E available and Source
E position LEDs flash, 1 second on and 1 second off.

TP-6865 4/14 11Section 1 Operation
Press and hold the Test pushbutton for about 2 seconds
to end the test. The retransfer sequence operates as
though Source N has been restored after a failure. The
load is transferred back to source N. All time delays are
executed and an in-phase transfer will occur if enabled.
The Source E LEDs light during the time delays. The
generator set shuts down.
If Source E is lost during the test and Source N is
available, the transfer switch will immediately transfer to
the Source N position, bypassing all time delays. If
source N is lost during a loaded test with the contactor in
the standby position, the test will continue to run.
1.5 Automatic Operation Test
Check the transfer switch’s automatic control system
immediately after the voltage check. Review the
operation instructions in Section 1 before proceeding.
Note: Close and lock the enclosure door before starting
the test procedure.
Follow the procedure below to start a loaded test. Verify
that the ATS starts the generator set and transfers the
load to the emergency source, executing all time delays
that are set up to operate during a loss of the normal
source. End the test and verify that the transfer switch
transfers the load back to the normal source and
removes the engine start signal, executing all
appropriate programmed time delays. Refer to Section
2.2.3 for a more detailed description of the test
sequence of operation.
Note: If the standby source fails during a loaded test,
the ATS will immediately attempt to transfer to the
preferred source.
Automatic Operation Test Procedure
1. Check the controller LED indicators to verify that
the Source N Position and Source N Available
indicators are lit.
2. Verify that the generator set master switch is in the
AUTO position.
3. Press and hold the Test button for 6 seconds or
longer to start a loaded test.
4. Verify that the generator set starts and the Source
E Available LED lights.
5. Verify that the switch transfers the load to Source E.
Observe the controller LEDs and display as the
time delays execute and the load is transferred.
After the preferred-to-standby transfer time delay,
verify that the Source N Position LED turns off and
the Source E Position LED lights, indicating thatthe
switch has transferred the load to Source E.
6. Press and hold the Test pushbutton for about 2
seconds to end the test.
7. Verify that the switch transfers the load back to
Source N. After the standby-to-preferred time
delay, verify that the Source E Position LED goes
out and the Source N Position LED lights,
indicating that the switch has transferred the load to
Source N.
8. After the engine cooldown time delay expires, the
engine start signal is removed. Verify that the
generator set stops.
Note: The generator set may have an engine cooldown
time delay that causes the generator set engine
to run after the transfer switch engine start signal
is removed.

TP-6865 4/1412 Section 1 Operation
1.6 Exercise
Set the exerciser after the ATS is installed. The exercise
automatically runs the generator set for 20 minutes each
week.
If a system test is active when the exercise is scheduled
to occur, the exercise is skipped. A preferred-source
failure during an exerciser period causes the exercise to
be terminated and normal ATS operation to resume.
1.6.1 Exercise Schedule
Pressing the exercise button to start a loaded or
unloaded exercise as described in the following
sections sets the exercise time and day. The system will
exercise at the same time and day each week.
To change the schedule, simply start a new exercise on
the desired day and time.
To start and stop the generator set without changing the
exercise schedule, use the Test button. See Section 1.4
for instructions.
1.6.2 Unloaded Exercise
An unloaded exercise starts and runs the generator set
for 20 minutes without transferring the load. Press and
hold the exercise button for 3--5 seconds to start an
unloaded exercise. During an unloaded exercise, the
Source E available LED flashes, 0.5 seconds on and 2
seconds off.
1.6.3 Loaded Exercise
A loaded exercise starts the generator set and transfers
the load from the normal source to Source E. Press and
hold the Exercise button for 6 seconds or longer to start
a loaded exercise. During a loaded exercise, the
Source E available and Source E position LEDs flash,
0.5 seconds on and 2 seconds off. After 20 minutes, the
load transfers back to the normal source and the
generator set shuts down.
1.6.4 Stopping an Exercise
If it is necessary to stop an exercise while it is running,
press and hold the exercise button for 2 seconds.
Stopping an exercise does not affect the weekly
exercise schedule.
1.6.5 Optional Programmable Exerciser
A programmable exercise timer is available. The
optional exerciser allows scheduling of additional
loaded or unloaded exercises. See Section 6.4 for more
information.

TP-6865 4/14 13Section 1 Operation
1.7 Warnings and Faults
When a fault exists, the System Alert indicator LED turns
on and the related output is activated. If the output is
assigned to the common fault, the common fault output
is also activated. See Figure 1-4 for the location of the
System Alert indicator.
GM46892
1. System Alert LED
1
Figure 1-4 Fault Indication
ATS warnings and faults are shown in Figure 1-5.
There are three types of warning/fault conditions:
Warning. Warnings automatically reset with a source
availability change or a transfer request.
Fault Requiring Manual Reset. Under these
conditions, normal ATS operation is halted. Active
modes are turned off. If the contactor is in the Source N
position, the engine cooldown time delay executes and
the engine start contacts open, allowing the generator
set to shut down. See Section 1.7.1 for instructions to
reset faults.
Self Resetting Faults. Under these conditions, active
modes are turned off. If the contactor is in the Source N
position, the engine cooldown time delay executes and
the engine start contacts open, allowing the generator
set to shut down. When the fault condition is corrected,
the fault is automatically cleared from the controller and
normal ATS operation continues.
Condition Type Description
Failure to Acquire Standby Source Warning The source voltage did not reach the acceptable range within a set
time (see Time Delays). For example, the Source E generator set
did not start.
IPM Synching
(In-Phase Monitor Synching)
Warning (status) The two sources did not come into phase within the Fail to
Synchronize time delay.
Note: If the sources do come into phase after the time delay
expires, the warning is automatically cleared and normal ATS
operation continues.
Failure to Transfer Warning The signal to transfer is sent to the contactor and the main shaft
auxiliary switch fails to indicate a complete ATS position change.
The controller will attempt to transfer the unit three times before the
fault is indicated.
Src N (or Src E) Rotation Err Self-Resetting Fault The detected phase rotation of one or both sources does not match
the preselected setting.
Auxiliary Switch Fault Manual Reset Fault The main shaft auxiliary switches indicate that the ATS is in more
than one position, or the position changed when no signal was sent
to initiate the change.
Auxiliary Switch Open Manual Reset Fault The main shaft auxiliary switches indicate that the ATS is in neither
position (all inputs are open).
External Fault Self-Resetting Fault The external input dedicated to this condition is closed.
Figure 1-5 Warnings and Faults

TP-6865 4/1414 Section 1 Operation
1.7.1 Fault Reset
To clear a fault or warning condition and reset the
System Alert LED, press the Test and Exercise buttons
at the same time and hold for 2 seconds. See
Figure 1-6.
1
GM85888
1. Test button
2. Exercise button
Press and hold the Test and Exercise buttons for 2 seconds to clear a
fault condition.
2
Figure 1-6 Fault Reset
1.8 Controller Reset
1.8.1 Reboot
To reboot the controller processor while retaining all
parameter settings, press the Test and Exercise buttons
at the same time and hold for 15 seconds.
1.8.2 Reset to Default Settings
A personal computer with KohlerrSiteTechtsoftware
can be used to reset the controller to factory defaults, if
necessary. SiteTech software is only available to Kohler
authorized distributors or dealers.
Note: Resetting to the default parameters will reset all
parameters, including the system voltage and
frequency, to a factory default setting. The
default system voltage and frequency settings
may not match the settings for your application.
The transfer switch will not operate correctly if the
system voltage and frequency do not match the
sources. Use SiteTech software to set the system
voltage and frequency after resetting to the default
parameters.
Check the system operation to verify the settings after
resetting.

TP-6865 4/14 15Section 2 Sequence of Operation
Section 2 Sequence of Operation
2.1 Controller Power--up/Reset
Following is an explanation of the sequence of operation
when power is initially applied to the controller or a
controller reset occurs.
1. Controller self test is executed.
2. System parameters are downloaded from
nonvolatile memory.
3. Contactor position and source availability are
determined.
4. If neither source is acceptable, the contactor does
not change position.
5. If both sources are available, the controller
immediately transfers the contactor to the
preferred source.
6. If only one source is available, the controller
immediately transfers the contactor to that source,
executing only the off-position and load control
time delays.
If the available source is the preferred source, and
the contactor is in the standby position, the
contactor transfers to preferred, the engine
cooldown time delay runs, and then the engine
start contacts open.
If the available source is the preferred source and
the contactor is already in the preferred position,
the engine start contacts open immediately,
bypassing the engine cooldown time delay.
2.2 Sequence of Operation
The Sequence of Operation describes the transfer
switch normal operation. The MPAC 750 controller
operates using standard transition only (no
programmed- or closed-transition operation).
Operation can be affected by faults such as the normal
or emergency contacts failing to open or close when
signaled to do so.
2.2.1 Source N Loss and Return
Following is an explanation of the transfer switch
sequence of operation when Source N failure is
detected.
Source N Fails
1. Engine start time delay expires.
2. The generator is signaled to start.
3. The generator starts and Source E becomes
available.
4. Preferred-to-standby time delay expires.
5. Contactor transfers to Source E.
Source N Returns
1. Standby-to-preferred time delay expires.
2. Contactor transfers to Source N.
3. Engine cooldown time delay expires.
4. The engine start contacts open, signaling the
generator to stop.
2.2.2 Exerciser Operation
Unloaded Exercise Sequence Starts
1. Exerciser timer begins.
2. The generator is signaled to start.
3. The generator starts and Source E becomes
available.

TP-6865 4/1416 Section 2 Sequence of Operation
Unloaded Exercise Sequence Ends
1. Engine cooldown time delay expires.
2. The engine start contacts open, signaling the
generator to stop.
Loaded Exercise Sequence Starts
1. Exerciser timer begins.
2. The generator is signaled to start.
3. The generator starts and Source E becomes
available.
4. Preferred-to-standby time delay and pre-transfer
load control sequences run.
5. Contactor transfers to Source E.
Source E Fails (Source N is available)
1. Exerciser is deactivated.
2. Contactor immediately transfers to Source N.
3. Immediate failure to acquire standby alarm.
4. Engine cooldown time delay expires.
5. Engine start contacts open.
Loaded Exercise Sequence Ends
1. Contactor transfers to preferred.
2. Engine cooldown time delay expires.
3. The engine start contacts open, signaling the
generator to stop.
2.2.3 Test Sequence
Unloaded Test Function is Initiated
1. The generator set is signaled to start.
2. The generator starts and Source E becomes
available.
Unloaded Test Function is Ended
1. Engine cooldown time delay expires.
2. The generator is signaled to stop.
Loaded Test Function is Initiated
1. The generator is signaled to start (engine start
contacts close).
2. The generator starts and Source E becomes
available.
3. Preferred-to-standby time delay expires.
4. Contactor transfers to Source E.
Source E Fails (Source N is available)
1. Test function is deactivated.
2. Contactor immediately transfers to Source N.
3. Immediate failure to acquire standby alarm.
4. Engine cooldown time delay expires.
5. Engine start contacts open.
Loaded Test Function is Ended
1. Standby-to-preferred time delay sequence runs.
2. Contactor transfers to Source N.
3. Engine cooldown time delay expires.
4. The engine start contacts open, signaling the
generator to stop.

TP-6865 4/14 17Section 3 Settings
Section 3 Settings
3.1 Introduction
The Decision-MakerrMPAC 750 controller is factory set
for your transfer switch. This section lists factory
settings and adjustment ranges.
If necessary, some settings can be changed using a
personal computer and KohlerrSiteTechrsoftware or
over Modbusr. SiteTech software is only available to
Kohler authorized distributors and dealers.
Use a USB cable with a male mini-B connector to
connect the controller to a laptop computer. The USB
connector is located on the front of the controller. See
Figure 1-1.
Using Modbus
Commercially available programs can be used to read
and change some settings over Modbus. For other
Modbus applications, the Modbus master must be
programmed to read the Modbus registers. Modbus
registers are published in TP-6113, Modbus Protocol
Operation Manual. A system designer trained in the
application of Modbus protocol must write and
thoroughly test the program before implementation.
3.2 System Setup
The transfer switch is factory-set with default settings for
time delays and other parameters. See Section 1 for the
default settings. Settings can be adjusted, if necessary
using a personal computer and KohlerrSiteTecht
software or over Modbus. SiteTech software is available
to Kohler authorized distributors and dealers.
Note: Use caution when changing transfer switch
settings. The source voltage and frequency
settings must match the values shown on the
transfer switch nameplate.
3.3 System Parameters
The transfer switch is factory-set for the transfer switch
model and rating. System parameters should not
require adjustment.
The system parameter factory settings are shown in
Figure 3-1. Note that some settings are not adjustable.
System Parameter Factory Setting
Transition type, standard
See the ATS
nameplate
Single/three phase
Operating voltage
Operating frequency (50 or 60 Hz)
Rated current
Transfer mode
(automatic or non-automatic)*
Phase rotation* ABC
Commit to transfer* No
Operating mode* Utility-to-Generator
In-phase monitor Disabled
In-phase monitor transfer angle 5_
* Not adjustable.
Figure 3-1 System Parameters
3.3.1 Transition Type, Standard
The MPAC 750 controller is only available for
standard-transition model transfer switches.
Standard-transition models (also referred to as open
transition) use a break-before-make transfer that does
not require source synchronization for transfer between
available sources.
Note: The transition type is determined by the ATS
model. Do not change the transition type.
3.3.2 Commit to Transfer: No
This setting is factory set to No and is not adjustable. If
the preferred source returns returns during the
transfer-to-standby time delay, the transfer sequence is
cancelled and the load is not transferred to the standby
source.
3.3.3 In-Phase Monitor
The in-phase monitor can be enabled or disabled for
standard-transition models. The in-phase monitor
operates prior to transfer when both sources are
available. Transfer is inhibited while both sources are
greater than 2 cycles apart. If the connected source falls
below the undervoltage dropout setting, the in-phase
monitor terminates and allows transfer.

TP-6865 4/1418 Section 3 Settings
The synchronism window has a default value of 5_and
is adjustable from 15_to 5_before synchronism only.
Settings can be changed using a personal computer
and Kohler SiteTech software or over Modbus. Contact
your distributor or dealer for service.
The In-Phase Monitor Sync Output is activated if the
sources do not synchronize within 60 seconds.
3.4 Voltage Pickup and Dropout
Settings
The controller senses the voltage on both sources with
an accuracy of ±0.5%. A source is considered
available when its voltage is within the range of dropout
settings. If the voltage of the active source is outside the
acceptable range for a length of time longer than the
debounce time, the system attempts to transfer the load
to the alternate source. The debounce time prevents
nuisance transfers caused by brief voltage spikes and
dips.
See Figure 3-2 for default settings and adjustment
ranges.
Settings
Default
Setting Adjustment Range [
Under voltage
dropout
90% of pickup 75% to 98% of Pickup
Under voltage
pickup
90% of nominal 85% to 100% of Nominal
Over voltage
dropout
115% 106% to 135% of
Nominal
Over voltage
pickup
95% of dropout 95 to 100% of Dropout
Debounce time 0.5 seconds 0.1 to 9.9 seconds
[Settings can be changed using a PC with SiteTech software
or over Modbus.
Figure 3-2 Normal Source Pickup and Dropout
Settings
3.5 Time Delays
The factory settings and adjustment ranges for the time
delays are shown in Figure 3-3.
The engine start time delay and transfer time delays can
prevent nuisance transfers caused by brief voltage dips
or surges.
The engine cooldown time delay holds the engine start
contacts closed for a designated time after transfer to
allow the generator set to run without load before
shutting down.
If the standby source does not reach acceptable voltage
and stabilize within the allowed time, the Fail to Acquire
Standby Source fault is activated.
Time Delay Description
Factory
Setting
Adjustment
Range [
Engine Start 3sec 0--6 sec
Engine Cooldown 5min.
0--60 min
Transfer, preferred to standby 3sec
Transfer, standby to preferred 15 min
Fail to Acquire Stby 1min
Fail to Synch 1min NA
[PC with SiteTech software required.
Figure 3-3 Time Delay Settings
3.6 Programmable Inputs and
Outputs
The controller includes connections for two
programmable inputs and two programmable outputs.
Inputs and outputs are unassigned until the installer
assigns a function to the I/O.
The programmable inputs and outputs can be assigned
to the functions shown in Figure 3-4 and Figure 3-5.
Programmable inputs and outputs can be assigned in
two ways:
DUsing a PC with KohlerrSiteTechtsoftware.
SiteTech software is available only to Kohler
authorized distributors and dealers.
DOver Modbus; see TP-6113, Modbus Protocol
Manual, for Modbus registers.
Programmable input functions correspond to the
connections to the transfer switch controller. Do not
change the programmable input assignments without
verifying the input connections to the transfer switch.
See the transfer switch installation manual for
connection information for controller inputs and outputs.

TP-6865 4/14 19Section 3 Settings
3.6.1 Input Functions
Available inputfunctions are shown in Figure 3-4. Some
inputs will trigger an indicator LED on the user interface
and/or display a message on the LCD screen when they
are activated.
All of the inputs may be assigned to either one or both of
thecommonalarms.
Remote Test Input. Activating the input starts a test,
and deactivating the input stops the test. Tests follow
the sequence described in Sections 1.4 and 2.2.3.
If a local test is already running, activating the remote
test input will stop the local test. A remote test can be
stopped locally, if necessary, by pressing and holding
the TEST button on the controller for about 2 seconds.
The default type for a remote test is “unloaded.” To
change the remote test type, use a computer and
KohlerrSiteTechtSoftware to set the Remote Test
Loaded parameter. Alternatively, set the remote test
type over Modbus.
The optional programmable exerciser uses the remote
test input. See the instructions provided with the
exerciser for more information.
Programmable
Inputs LED
«
LED
Inhibit Transfer
(maintenance mode)
None Flashing
Remote Common Alarm Steady None
Remote Test None None
Figure 3-4 Available Programmable Inputs
3.6.2 Output Functions
Output functions are shown in Figure 3-5. Information
about selected output functions is shown below. Refer
to the section number shown in Figure 3-5 for more
information about the output function.
Programmable Output Type
See
Section
Aux Switch Fault Fault 1.7
Aux Switch Open Fault 1.7
Common Alarm Active (1 and 2) Fault 3.7
Contactor in Preferred Position Monitor —
Contactor in Source E Position Monitor —
Contactor in Source N Position Monitor —
Contactor in Standby Position Monitor —
Exerciser Active Monitor 2.2.2
Fail to Acquire Standby Fault 1.7
Fail to Transfer Fault 1.7
In-Phase Monitor Sync Control 3.3.3
Not in Auto Monitor 1.3.2
Source E (Phase) Rotation Error Fault —
Source N (Phase) Rotation Error Fault —
Test Mode Active Monitor 1.4
Figure 3-5 Available Programmable Outputs

TP-6865 4/1420 Section 3 Settings
3.7 Common Alarms
Functions can be assigned to two alarm groups. The
groups can then be assigned to programmable outputs,
if desired. Any function assigned to the Common Alarm
triggers the Common Alarm programmable output. See
Section 3.6, Programmable Inputs and Outputs, for
more information about programmable outputs.
Use KohlerrSiteTechtsoftware or Modbus to assign
events to the controller’s common alarm groups. See
Figure 3-6 for a list of functions that can be assigned to
thecommonalarm.
Alarm Descriptions
Auxiliary Switch Fault
Auxiliary Switch Open
Contactor in Preferred
Contactor in Source E Position
Contactor in Source N Position
Contactor in Standby Position
Exerciser Active
Fail to Acquire Standby Source
Fail to Transfer
In Phase Monitor Synching
Not in Auto
Remote Common Alarm
Source E Available
Source N Available
Source N Rotation Error
Source E Rotation Error
System Ready
Test Mode Active
Figure 3-6 Alarm Descriptions
3.8 Communications
Use a personal computer with Kohler SiteTech software
or Modbus to set the communication parameters for
serial or Ethernet connections. See Section 4,
Communications, for instructions.