Page 1
OT III
Redistribution or publication of this document
by any means, is strictly prohibited.
Transfer Switch
1200 to 3000 Amperes
Utility-to-Utility
:GEFHDC ?%=%-%
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Page 2
8; <C> E? .EDI>DIH
Redistribution or publication of this document
by any means, is strictly prohibited.
SECTION TITLE PAGE
1INTRODUCTION 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operator’s Manual1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Switch Application 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Transfer Switches 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model Identification 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
How to Obtain Service1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2DESCRIPTION 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cabinet2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Switch 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronic Control System 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3OPERATION 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Operation 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual Operation 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Preventive Maintenance3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4TROUBLESHOOTING 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Switch Does Not Transfer Automatically4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Transfer Switch Does Not Retransfer Automatically4-1. . . . . . . . . . . . . . . . . . . . . . . . . . .
WARNING
INCORRECT SERVICE OR REPLACEMENT OF PARTS CAN RESULT IN
DEATH, SEVERE PERSONAL INJURY, AND/OR EQUIPMENT DAMAGE.
SERVICE PERSONNEL MUST BE QUALIFIED TO PERFORM ELECTRICAL
AND/OR MECHANICAL SERVICE.
i
Page 3
7;?>IK 5G>=;JIBEDH
Redistribution or publication of this document
by any means, is strictly prohibited.
This manual includes the following symbols to indi-
cate potentially dangerous conditions. Read the
manual carefully and know when these conditions
exist. Then take the necessary steps to protect per-
sonnel and the equipment.
This symbol warns of immediate
hazards that will result in severe personal injury
or death.
:-63130
unsafe practice that can result in severe per-
sonal injury or death.
.-98143
unsafe practice that can result in personal in-
jury or product or property damage.
AC and DC voltages in the transfer switch components present serious shock hazards that can result
in severe personal injury or death. Read and follow
these instructions.
Keep the transfer switch cabinet closed and locked.
Make sure only authorized personnel have the cabi-
net and operational keys.
This symbol refers to a hazard or
This symbol refers to a hazard or
Due to the serious shock hazard from high voltages
within the cabinet, all service and adjustments to
the transfer switch must be performed only by an
electrician or authorized service representative.
If the cabinet must be opened for any reason, re-
move AC power to the automatic transfer switch. If
the instructions require otherwise, use extreme
caution due to the danger of shock hazard.
Place rubber insulative mats on dry wood platforms
over metal or concrete floors when working on any
electrical equipment. Do not wear damp clothing
(particularly wet shoes) or allow skin surfaces to be
damp when handling any electrical equipment.
Jewelry is a good conductor of electricity and
should be removed before working on the electrical
equipment.
Do not work on this equipment when mentally or
physically fatigued, or after consuming alcohol or
any drug that makes the operation of equipment un-
safe.
ii
T12-UU-1
Page 4
&$ 4F>G;IBED
Redistribution or publication of this document
by any means, is strictly prohibited.
OPERATOR’S MANUAL
This operator’s manual provides information necessary for operation of 1200– to 3000–ampere, util-
ity–to–utility transfer switches. The utility–to–utility
control automatically directs transfer of the load
from one utility power source to another, providing
nearly continuous power.
TRANSFER SWITCH APPLICATION
Transfer switches are an essential part of a build-
ing’s standby or emergency power system. The
Normal power source (source 1) is backed up by an
Emergency power source (source 2). A transfer
switch supplies the electrical load with power from
one of these two power sources.
The load is connected to the common of the transfer
switch (Figure 1-1). Under normal conditions, the
load is supplied with power from the Normal source
(as illustrated). If the Normal power source is interrupted, the load is transferred to the Emergency
power source. When Normal power returns, the
load is retransferred to the Normal power source.
The transfer and retransfer of the load are the two
most basic functions of a transfer switch.
=9?</1 (
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FIGURE 1-1. LOAD TRANSFER SWITCH
(TYPICAL FUNCTION)
SC1101
AUTOMATIC TRANSFER SWITCHES
Automatic transfer switches, capable of automatic
operation without operator involvement, perform
the following basic functions:
1. Sense the interruption of the Normal power
source.
2.Transfer the load to the Emergency power
source.
3.Sense the return of the Normal power source.
4. Retransfer the load to the Normal power
source.
1-1
Page 5
MODEL IDENTIFICATION
Redistribution or publication of this document
by any means, is strictly prohibited.
Identify your model by referring to the Model and
Specification number as shown on the nameplate.
Electrical characteristics are shown on the lower
portion of the nameplate, which is located on the
cabinet door.
If it is necessary to contact a dealer or distributor re-
garding the transfer switch, always give the com-
plete Model, Specification, and Serial number. This
information is necessary to properly identify your
unit among the many types manufactured.
HOW TO OBTAIN SERVICE
For the name of your local Cummins /Onan or
Onan-only distributor in the United States or Canada, call 1-800-888-ONAN. (This automated serv-
ice utilizes touch-tone phones only.) By entering
your area code and the first three digits of your local
telephone number, you will receive the name and
telephone number of the distributor nearest you.
For the name of your local Cummins-only distributor, or if you need more assistance, please call
Onan Corporation, 1-612-574-5000, 7:30 AM to
4:00 PM, Central Standard Time, Monday through
Friday.
When the transfer switch requires servicing, con-
tact your nearest dealer or distributor. Factory-
trained Parts and Service representatives are
ready to handle all your service needs.
If unable to locate a dealer or distributor, consult the
Yellow Pages. Typically, our distributors are listed
under:
GENERATORS-ELECTRIC,
ENGINES-GASOLINE OR DIESEL, OR
RECREATIONAL VEHICLES-EQUIPMENT,
PARTS AND SERVICE.
When contacting your distributor, always supply the
complete Model Number and Serial Number as
shown on the nameplate.
Cummins is a registered trademark of Cummins Engine Company.
Onan is a registered trademark of Onan Corporation.
1-2
Page 6
'$ />H=GBFIBED
Redistribution or publication of this document
by any means, is strictly prohibited.
Automatic transfer switches control transfer of the
load to either Normal power source (source 1) or to
Emergency power source (source 2) without opera-
tor involvement.
CABINET
The standard cabinet (Figure 2-1) meets the re-
quirements for a UL Type 1 cabinet. This type is
designated as a general-purpose, indoor cabinet.
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Indicator Lamps
There are four indicator lamps on the cabinet door.
The Source 1 Available and Source 2 Available
lamps are lit whenever their corresponding power
sources are producing power. These two lamps
can be lit simultaneously.
The Source 1 Connected lamp is lit when the auto-
matic transfer switch is in the Source 1 (normal) po-
sition.
The Source 2 Connected lamp is lit when the auto-
matic transfer switch is in the Source 2 (emergency)
position.
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FIGURE 2-1. CABINET WITH OPTIONS
2-1
Page 7
Source Selector Switch
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by any means, is strictly prohibited.
TRANSFER SWITCH
This two–position switch is used to select which
source is preferred and which source is the backup.
In the Source 1 position, the Normal power source
supplies the load power until a power interruption
occurs.
In the Source 2 position, the Emergency power
source supplies the load power until a power interruption occurs.
Optional Auto/Manual Switch
The optional Auto/Manual switch is used to enable
or disable the automatic retransfer function. This
switch has two positions. In the Auto position, normal automatic retransfer is enabled. In the Manual
position, automatic retransfer (from the non-pre-
ferred source back to the preferred source) is dis-
abled; only manual retransfer (using the Preferred
Source Selector switch) is possible. In the event of
power source failure, however, the Power Sentry
control logic will ignore the Auto/Manual switch and
initiate retransfer to the other source.
When the optional Auto/Manual switch is installed,
the standard Source Selector Switch is replaced with
a three-position, spring-return-to-center switch.
Optional Meter Package
The optional meter package includes an AC amme-
ter, an AC voltmeter, a frequency meter, and a
phase selector switch.
AC Voltmeter: The voltmeter measures line-to-line
voltage of the selected power source.
AC Ammeter: The ammeter measures the line cur-
rents of the load.
Frequency Meter: This meter measures the output
frequency of the selected power source in hertz.
Phase Selector Switch: This switch is used to se-
lect the source (1 or 2) and phase to be measured.
The transfer switch (Figure 2–2) opens and closes
the contacts that transfer the load between Normal
and Emergency power. The transfer switch is mechanically interlocked to prevent simultaneous
closing to both power sources. The main parts of
the transfer switch discussed here are the contact
assemblies, linear actuators, Motor Disconnect
switch, and auxiliary contacts.
Contact Assemblies
The automatic transfer switch has either three or
four poles. Three pole transfer switches are provided with a neutral bar. The contact assemblies
make and break the current flow. When closed to
either the source 1 or the source 2 power source,
the contacts are mechanically held. A mechanical
interlock prevents them from closing to both power
sources at the same time.
Linear Actuators
The linear actuators are the devices that move the
contact assemblies between the Normal (source 1)
power source and the Emergency (source 2) power
source. Linear actuator operation is initiated auto-
matically with automatic transfer switches. Refer to
the Operation section.
.-98143
Do not initiate rapid cycling of the
linear actuators. Rapid switching will cause ac-
tuator failure. The maximum allowable cycle
rate for the linear actuators is one cycle in two
minutes.
Motor Disconnect Switch
The Motor Disconnect toggle switch, on the acces-
sory control panel, enables and disables the linear
actuators. Place the switch in the Auto position to
enable the linear actuators. Place the switch in the
Off position to disable the linear actuators.
Auxiliary Contacts
Auxiliary contacts are provided on the Normal
(source 1) and Emergency (source 2) sides of the
transfer switch. They are actuated by operation of
the transfer switch during transfer and retransfer.
The Normal side auxiliary contact switch is actuated
when the transfer switch is in the Normal position.
The Emergency side auxiliary contact switch is actuated when the transfer switch is in the Emergency
position. The auxiliary contacts have current ratings of 10 amperes at 250 VAC. The contacts are
wired to terminal block TB1.
2-2
Page 8
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FIGURE 2-2. INTERIOR/COMPONENTS
2-3
Page 9
ELECTRONIC CONTROL SYSTEM
Redistribution or publication of this document
by any means, is strictly prohibited.
This section describes the standard and optional
components of the electronic control system.
:-63130
of electronic control modules can cause death,
severe personal injury, and equipment or prop-
erty damage. Calibration and adjustment of
these components must be performed by tech-
nically qualified personnel only.
All calibration and adjustment procedures are described in the Installation manual (which was
shipped with the transfer switch) and in the Service
manual (which is available through your distributor).
The most important component of the electronic
control system is the Power Sentry control (Figure
2–2). The Power Sentry includes voltage sensing
circuits, time delay circuits and control relays.
There are also several adjustment potentiometers
and indicator lamps on the Power Sentry. The ad-
justments must be performed only by qualified serv-
ice personnel.
:-63130
actuators could cause severe personal injury.
Disable the actuators before making any adjust-
ments.
Improper calibration or adjustment
Accidental actuation of the linear
To set this time delay, align the slot on the potenti-
ometer with the desired marking on the Power Sen-
try cover.
Undervoltage Sensing
Two voltage sensors, one for the Normal side and
one for the Emergency side, monitor source volt-
ages for an undervoltage condition and generate
signals, which are sent to the time delay module. If,
for example, an undervoltage condition is sensed
on the Normal source, the voltage sensor module
sends a signal to the time delay module that initiates
and controls the transfer of load.
The standard transfer switch has undervoltage
sensing for all phases of the Normal and Emergency power sources.
Overvoltage and Frequency Sensing
Option
Overvoltage and frequency sensing are available
as a single option.
Overvoltage Sensing: With optional overvoltage
sensing, the Normal and Emergency sources are
monitored for an overvoltage condition.
As with the standard undervoltage sensing, the volt-
age sensors signal the time delay module, which
controls the transfer or retransfer sequence.
Place the Motor Disconnect switch (Figure 2–2)
in the Off position when making adjustments.
Return the switch to the Auto position after ad-
justments are completed.
Power Sentry Time Delays
Transfer Time Delay: This delay prevents “nui-
sance” transfers to the backup power source
caused by brief line fluctuations. After the delay, the
transfer switch transfers the load to the backup
power source. It has an adjustable range of 0 to 120
seconds.
To set this time delay, align the slot on the potenti-
ometer with the desired marking on the Power Sen-
try cover.
Retransfer Time Delay: This delay begins the mo-
ment the preferred source voltage and frequency
return. After the delay, the transfer switch can
retransfer the load to the preferred source. The de-
lay allows the preferred source to stabilize before
retransfer. It has an adjustable range of 0 to 30 min-
utes.
An adjustable time delay (0 to 120 seconds) overrides momentary overshoots in voltage.
To set this time delay, align the slot on the potenti-
ometer with the desired marking on the Power Sen-
try cover.
Frequency Sensing: With optional frequency
sensing, the Normal and Emergency sources are
monitored for variations in frequency. The sensors
determine whether the source is within an adjust-
able bandwidth.
As with the standard undervoltage sensing, the fre-
quency sensors signal the time delay module,
which controls the transfer or retransfer sequence.
An adjustable time delay (0 to 15 seconds) allows
the control to ignore momentary dips or rises in fre-
quency.
To set this time delay, align the slot on the potenti-
ometer with the desired marking on the Power Sen-
try cover.
2-4
Page 10
Programmed Transition Option
Redistribution or publication of this document
by any means, is strictly prohibited.
The optional Program Transition module (Figure
2-3) is used to introduce a pause during transition.
Programmed transition allows the transfer switch to
assume a mid-transition position for an adjustable
interval of time. In this position, the load is not con-
nected to either power source. This feature allows
residual voltage from inductive loads to decay to an
acceptable level before transfer is completed.
The length of time that the transfer switch is in the
midposition can be adjusted from 0 to 7.5 seconds
or 0 to 60 seconds, depending on the timer option.
The proper adjustment is a function of the load.
To set the time delay, align the slot on the potenti-
ometer with the desired marking on the faceplate
(Figure 2–3).
If a time delay is desired, make sure that the Delay/
No Delay switch is in the Delay position.
Signal Module Option
The main function of the optional Signal Module is
to delay transfer (or retransfer) for a preset time
while operating a signal contact to give warning that
a transfer (or retransfer) is about to occur. This op-
tion is typically used in elevator applications.
SC1583
FIGURE 2-3. PROGRAM TRANSITION MODULE
This module also provides three other sets of form
C signal contacts.
The Signal Module has one adjustable timer. The
Elevator Signal delay controls the timing of two
events. It delays transfer/retransfer and energizes
the Elevator Transfer Signal relay during the delay
period.
This time delay is adjustable over a range of 0 to 50
seconds.
To set the time delay, align the slot on the potenti-
ometer with the desired marking on the faceplate
(Figure 2–4).
If a time delay is desired, make sure that the Delay/
No Delay switch is in the Delay position.
SC1584
FIGURE 2-4. SIGNAL MODULE
2-5
Page 11
Alarm Module Option
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by any means, is strictly prohibited.
The optional alarm module (Figure 2-5) provides an
audible indication that the transfer switch has trans-
ferred to the source 2 power source.
A push button on the alarm module provides a
means to silence the horn.
The Alarm lamp indicates that the transfer switch is
in the Source 2 Connected position. If the horn is
silenced, the Horn Silenced lamp will also light.
Both lamps will stay lit until the transfer switch
moves from the Source 2 Connected position to the
disconnected (neutral) or Source 1 Connected position.
Auxiliary Relay Option
Optional auxiliary relays provide contacts for ener-
gizing external alarms, remote indicators, and control equipment such as louver motors and water
pumps.
(%%#(,,+
FIGURE 2-5. ALARM MODULE
2-6
Page 12
($ 4F>G;IBED
Redistribution or publication of this document
by any means, is strictly prohibited.
AUTOMATIC OPERATION
The automatic transfer switch is set for automatic
operation by placing control switches in the posi-
tions given below.
Motor Disconnect Switch: Auto position.
Source Selector switch: Source 1 or Source 2.
.-98143
Do not initiate rapid cycling of the
linear actuators. Rapid switching will cause ac-
tuator failure. The maximum allowable cycle
rate for the linear actuators is one cycle in two
minutes.
MANUAL OPERATION
The transfer switch has operator handles that are
intended for maintenance use only. Manual operation must be performed by qualified personnel under NO–LOAD CONDITIONS ONLY .
:-63130
Manual operation of the transfer
switch under load presents a shock hazard that
can cause severe personal injury or death. For
this reason, do not attempt to perform manual
operation of the transfer switch when it is under
load. Follow the “Safety Related Work Practices” listed in NFPA 70E.
Manual Transfer to Source 2 (Emergency)
If you determine that the Emergency (source 2)
power source is available but the transfer switch will
not automatically transfer (refer to the Trouble-
shooting section), perform this procedure to manu-
ally transfer to the Emergency source.
1. Open the source 1 and source 2 disconnect
switches or breakers that feed the transfer
switch.
2.When you are certain that neither source 1 nor
source 2 power is present at the transfer
switch, open the transfer switch cabinet door
and turn the Motor Disconnect switch to Off.
:-63130
Manual operation of the trans-
fer switch under load presents a shock haz-
ard that can cause severe personal injury or
death. For this reason, do not attempt to
perform manual operation of the transfer
switch when it is energized by either source
1 or source 2 power sources.
3.A manual operating handle is provided with the
transfer switch. The handle is a steel rod or
tube, with a knob or hand grip on one end. On
standard transfer switches (Figure 3-1), there
are two manual operator slots—one for the
Normal (source 1) contacts and one for the
Emergency (source 2) contacts.
First, insert the handle in the slot for the Normal
contacts and open the Normal contacts. Then,
insert the handle in the slot for the Emergency
contacts and close the Emergency contacts.
Be certain to push the handle all the way to the
LOCK position. A distinct over-center locking
action can be felt. Return the handle to its stor-
age position.
4-8061
183-310 58
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FIGURE 3-1. MANUAL OPERATION
3-1
Page 13
:-63130
Redistribution or publication of this document
by any means, is strictly prohibited.
Automatic transfer switch op-
eration results in rapid movement of the
manual operator mechanism and presents
a hazard of severe personal injury if the op-
erator handle is engaged in the mechanism.
Remove the handle and place it in its stor-
age position.
3.A manual operating handle is provided with the
transfer switch. The handle is a steel rod or
tube, with a knob or hand grip on one end. On
standard transfer switches (Figure 3-1), there
are two manual operator slots—one for the
Normal (source 1) contacts and one for the
Emergency (source 2) contacts.
4. After the switch has been transferred to source
2 and the operator handle has been removed
from the mechanism, close and lock the cabinet door.
5. Close the Emergency (source 2) disconnect
that feeds the transfer switch.
If the Motor Disconnect switch is placed back in
the Auto position, the transfer switch will trans-
fer load to the active power source. (If both
power sources are available, it will transfer the
load to the priority [selected] source).
6.If the transfer switch is not functioning correctly,
call your dealer or distributor immediately.
Manual Transfer to Source 1 (Normal)
If you determine that the Normal (source 1) power
source is available but the transfer switch will not
automatically retransfer (refer to the Troubleshoot-
ing section), perform this procedure to manually
retransfer to source 1.
1. Open the source 1 and source 2 disconnect
switches or breakers that feed the transfer
switch.
2.When you are certain that neither source 1 nor
source 2 power is present at the transfer
switch, open the transfer switch cabinet door
and turn the Motor Disconnect switch to Off.
:-63130
fer switch under load presents a shock haz-
ard that can cause severe personal injury or
death. For this reason, do not attempt to
perform manual operation of the transfer
switch when it is energized by either source
1 or source 2 power sources.
Manual operation of the trans-
First, insert the handle in the slot for the Emergency contacts and open the Emergency con-
tacts. Then, insert the handle in the slot for the
Normal contacts and close the Normal con-
tacts. Be certain to push the handle all the way
to the LOCK position. A distinct over-center
locking action can be felt. Return the handle to
its storage position.
:-63130
Automatic transfer switch op-
eration results in rapid movement of the
manual operator mechanism and presents
a hazard of severe personal injury if the op-
erator handle is engaged in the mechanism.
Remove the handle and place it in its stor-
age position.
4. After the switch has been transferred to source
1 and the operator handle has been removed
from the mechanism, close and lock the cabinet door.
5. Close the Normal (source 1) disconnect that
feeds the transfer switch.
If the Motor Disconnect switch is placed back in
the Auto position, the transfer switch will trans-
fer load to the active power source. (If both
power sources are available, it will transfer the
load to the priority [selected] source).
6.If the transfer switch is not functioning correctly,
call your dealer or distributor immediately.
3-2
Page 14
PREVENTIVE MAINTENANCE
Redistribution or publication of this document
by any means, is strictly prohibited.
Performing the yearly preventive maintenance procedures in Ta ble 3-1 will result in operational reliability of the
transfer switch.
The following procedures must only be performed by technically qualified personnel, following the procedures
provided in the Service manual (962-0513). If repair or replacement of components is necessary, call
your dealer or distributor.
:-63130
that can cause severe personal injury or death. In addition, incorrect installation, service, or parts re-
placement can result in severe personal injury, death, and/or equipment damage. Therefore, all cor-
rective service procedures must only be performed by technically qualified personnel, following the
procedures provided in the Service manual (962-0513).
:-63130
death unless all AC power is removed. Be sure to disconnect AC line power before servicing.
1. DISCONNECT ALL SOURCES OF AC POWER:
Disconnect both AC power sources from the transfer switch before continuing.
2.CLEAN
3.INSPECT
4. PERFORM ROUTINE MAINTENANCE
5. CONNECT AC POWER AND CHECK OPERATION
AC power within the cabinet and the rear side of the cabinet door presents a shock hazard
The transfer switch presents a shock hazard that can cause severe personal injury or
TABLE 3-1. ANNUAL PREVENTIVE MAINTENANCE
a.Thoroughly dust and vacuum all controls, meters, switching mechanism components, interior
buswork, and connecting lugs.
b.Close the cabinet door and wash exterior surfaces with a damp sponge (mild detergent and
water). Do not allow water to enter the cabinet, especially at meters, lamps, and switches.
a.Check buswork and supporting hardware for carbon tracking, cracks, corrosion, or any other
types of deterioration. If replacement is necessary, call your dealer or distributor.
b.Check stationary and movable contacts. If contact replacement is necessary, the procedures are
described in section 4 of the Service manual (962-0513).
c.Check system hardware for loose connections. Tighten as indicated in step 4.
d. Check all control wiring and power cables (especially wiring between or near hinged door) for
signs of wear or deterioration.
e. Check all control wiring and power cables for loose connections. Tighten as indicated in step 4.
f. Check the cabinet interior for loose hardware. Tighten as indicated in step 4.
Tighten buswork, control wiring, power cables, and system hardware, as necessary. Hardware
torque values are given in section 4 of the Service manual (962-0513). Retorque all cable lug
connections. Lug torque requirements are listed in section 1 of the Service manual.
a.Connect the both AC power sources.
c.Test system operation as described in this section. Close and lock the cabinet door.
3-3
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by any means, is strictly prohibited.
3-4
Page 16
)$ 8GEJ<C>HAEEIBD@
Redistribution or publication of this document
by any means, is strictly prohibited.
The following procedures describe preliminary
troubleshooting checks. If the trouble persists, call
your dealer or distributor.
:-63130
rear side of the cabinet door presents a shock
hazard that can cause severe personal injury or
death. For this reason; do not touch or allow
clothing, tools, or jewelry to contact exposed
electrical terminals whenever the cabinet door
is open. Make sure you are standing on a dry,
insulating surface.
AC power within the cabinet and the
TRANSFER SWITCH DOES NOT
TRANSFER AUTOMATICALLY
1. Check the Motor Disconnect switch. It should
be in the Auto position.
2.Is the Source Selector switch in the correct po-
sition?
3.Has the transfer time delay expired?
4. Has the programmed transition time delay (if
equipped) expired?
5. Is backup source voltage sufficient to trigger
the backup source voltage sensor?
TRANSFER SWITCH DOES NOT
RETRANSFER AUTOMATICALLY
1. Check the Motor Disconnect switch. It should
be in the Auto position.
2.Is the Source Selector switch in the correct po-
sition?
3.Has the retransfer time delay expired?
4. Has the programmed transition time delay (if
equipped) expired?
5. Is preferred source voltage sufficient to trigger
the preferred source voltage sensor?
4-1
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by any means, is strictly prohibited.
4-2
Page 18
Cummins Power Generation
Redistribution or publication of this document
by any means, is strictly prohibited.
1400 73rd Avenue N.E.
Minneapolis, MN 55432
1-800-888-6626
763-574-5000 International Use
Fax: 763-528-7229
Cummins is a registered trademark of Cummins Inc.
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