AUTOMATIC TRANSFER SWITCH
CTS SERIES
AUTOMATIC
TRANSFER SWITCH
The Cat® CTS Series Automatic Transfer Switch
(ATS) is configurable for applications requiring the
dependability and ease of operation found in
a full featured power contactor type transfer switch.
The CTS Series is equipped with the MX250
controller that is designed for the most demanding
transfer or bypass switch applications.
DESIGN AND CONSTRUCTION FEATURES
● Double throw, interlocked operation
● Electrically operated, mechanically held
by a simple, over-center mechanism
● Silver alloy contacts with separate arcing
contacts on 600 amp and above
● Arc quenching grids, enclosed arc chambers,
and wide contact air gap for superior source to source isolation on all units
● Control circuit disconnect plug and drive inhibit
switch for safe maintenance
● Components accessible for inspection and
maintenance without removal of the switch
or the power conductors
● Mechanical indicator and contact chamber
cover designed for inspection, safety and
position designation
FEATURES
ELECTRICAL RATINGS
● Ratings 40 to 4000 amperes
● 2, 3 or 4 Poles
● NEMA 1, 3R, 4, 4X and 12
● Available to 600 VAC, 50 or 60 Hz
● Suitable for emergency and standby
applications on all classes of load,
100% tungsten rated through 400 amps
● UL 1008 listed at 480 VAC
● CSA C22.2 No. 178 certified at 600 VAC
● IEC 947-6-1 listed through 480 VAC
PERFORMANCE FEATURES
● Contact transfer speed less than 100
milliseconds
● High close-in and withstand capability
● Temperature rise test per UL 1008 conducted
after overload and endurance tests in
unventilated enclosure – exceeds UL
requirements
● Equipped with the MX250 Control Package
LEHE4651-04
AUTOMATIC TRANSFER SWITCH
THE CAT CTS SERIES OF AUTOMATIC
TRANSFER SWITCHES
transfer switch duty with dependability, versatility
The Cat CTS Series power contactor and user friendliness of prime concern.
Type transfer switch makes use of a fully
programmable/configurable microprocessor-based
controller to allow the utmost in application flexibility.
Further, the CTS Series is offered in a wide array of
configurations enabling it to meet the needs of even
the most highly critical load.
the door for ease of maintenance and separation
Available configurations include: from the power section. They are connected
40-4000 Amps:
● CTS Automatic Transfer Switches a disconnect plug that allows isolation of the
● CTSD Delayed Transition Transfer Switches control panel for maintenance.
● CTSM Manual Transfer Switches
100-4000 Amps: CTS SERIES METHOD OF OPERATION
● CTSCT Closed Transition Transfer Switches When the normal source fails or the voltage
● CBTS Automatic Transfer/Bypass Switches drops to a predetermined point (usually 80% of
● CBTSD Delayed Transition Bypass Switches nominal), if required, a circuit is closed to start
● CBTSCT Closed Transition Bypass Switches the engine generator set. When the emergency
source reaches 90% of rated voltage and 95% of
All CTS products meet or exceed industry rated frequency, the drive solenoid is energized
requirements to allow specification and through the emergency coil control relay, causing
installation with confidence. the main contacts to disconnect the load from
● UL 1008 listed through 480 VAC the normal source and connect it to the
● CSA C22.2 No. 178 listed through 600 VAC
● IEC 947-6-1 listed through 480 VAC
● Codes and Standards
NFPA 70, 99, 101, 110
NEC 517, 700, 701, 702
IEEE 446, 241
NEMA ICS2-447
● Controls tested in accordance with:
IEEE 472 (ANSI C37.90A)
EN55022 Class B (CISPR 22)
(Exceeds EN55011 & MILSTD 461 Class 3)
EN61000-4-2 Class B (Level 4)
EN61000-4-3 (ENV50140) 10v/m
EN61000-4-4
EN61000-4-5, IEEE C62.41 All CTS switches employ the simple “over-center”
EN61000-4-6 (ENV50141)
EN61000-4-11
● Equipment (Controls and Power Section)
Seismic Test Qualified to:
IBC-2003
IEEE-693-2005
● Enclosures meet the requirements of:
UL 508, UL 50, ICS 6, ANSI C33.76 and
NEMA 250
● Quality System:
ISO 9001 Registered
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This ruggedly built family of power contactor
switches has been specifically designed for
The CTS power panel components, consisting
of power switching contacts, drive mechanism
and terminal lugs, are mounted on a specially
formed backplane. Logic devices including
microprocessor control auxiliary time delays and
special accessory equipment are assembled on
with a numbered wiring harness equipped with
emergency source. After the drive solenoid has
completed its electrical stroke and is seated, the
emergency coil control relay opens to disconnect
it. The transfer switch is now mechanically locked
in the emergency position. When normal voltage is
restored to a predetermined point (usually 90% of
nominal), the control voltage sensing energizes.
The normal side coil relay closes, and after the
drive solenoid has completed its electrical stroke
and is seated, the coil control relay opens to
disconnect it. The transfer switch is now
mechanically locked in the normal position.
DRIVE MECHANISM
principle to achieve a mechanically locked position
in either normal or emergency and a high speed
drive assures contact transfer in 100 ms or less.
High contact pressure and positive mechanical
lock allow for high withstand and closing ratings,
far exceeding UL requirements.
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AUTOMATIC TRANSFER SWITCH
NEUTRAL SWITCHING
The CTS Series is available in true four pole designs
for multi-source power systems that require switching
the neutral. The neutral contact is on the same shaft
as the associated main contacts. This design ensures
positive operation, and prevents any possibility that
the neutral contact will fail to open or close, as is
possible when the neutral pole is an add-on
accessory. The neutral contacts are identical to the
main contacts, having the same current carrying and
high withstand /closing ratings as the mains. They are
designed to break last and make first to negate the
possibility of transients while switching the neutral.
SAFE MANUAL OPERATION
The CTS manual operator consists of a large,
easy-to-use handle that fits securely for manual
operation during installation and maintenance
or in an emergency.
Every CTS is provided with an operator inhibit
switch to disconnect the electrical drive prior to
maintenance. Fully enclosed wrap-around arc
covers shield the main contacts and mechanical
components, preventing operator exposure during
manual operation
TRANSFERRING LARGE MOTOR
OR HIGHLY INDUCTIVE LOADS
Some loads, especially large motors receive
severe mechanical stress if power is transferred
out of phase while the motor is still rotating.
Also, back EMF generated by a motor can result
in over currents that can blow fuses or trip circuit
breakers. The CTS Series offers four solutions
to these problems:
1. Optional Universal Motor Disconnect Contact:
This load control disconnects a large motor via
its control circuit for an adjustable period of time
prior to transfer in either direction. For switching
multiple motors, the motor disconnect contact
with staged restart disconnects the motors
prior to transfer and brings them back on line
sequentially.
2. Accessory R50 Phase Monitor: This feature
compares the phase angle between both sources
of power and prevents transfer until the two are
approximately in phase (within a self adjusting
range). The CTS’s high speed transfer action
coupled with the MX series microprocessor
control logic ensure closures at or near zero
degree phase difference
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3. Series CTSD: The CTSD offers a delayed
4. Series CTSCT: Cat closed transition
3
CTS SERIES ATS
400 amp, 2 pole
transition on transfer switches 40A and above.
This programmed center-off position allows for
the full decay of rotating motors or transformer
fields. It can also be used for load shedding
of selected circuits or other applications which
require a means to disconnect the load from
either source. Many UPS system manufacturers
recommend delayed transition switches to
support sequencing of their systems. Reference
the CTSD supplement for further details.
switches combine CTSD operation during a
source failure with a highly engineered control
system that allows momentary paralleling (100
ms) of two acceptable sources, thereby limiting
the impact of transfer on the load. Reference
the CTSCT supplement for further details.
AUTOMATIC TRANSFER SWITCH
STANDARD FEATURES (MSTD PACKAGE)
Feature Function
6/P Momentary Test Switch
J2E/J2N Adj. over/under freq (S1 and S2)
A3 Aux Contact (S2 position)
L1/L2 Source Position LEDs
A4 Aux Contact (S1 position)
L3/L4 Source Available LEDs
Calibrate Volt. and Freq. calibration
LN/P Center-Off Position LCD*
CDT Load/No-Load Exerciser
P1 Source 2 Start Time Delay
DS Auto/Inhibit Switch (> 600A)
R50 In-Phase Monitor
DT Time Delay – Neutral to S1*
S13/P Transfer Commit
DW Time Delay – Neutral to S2*
T Source 1 Stable Time Delay
E Engine Start Contact
U Source 2 Stop Time Delay
EL/P Log of last 16 events and
System Data
VI Voltage Imbalance
K/P S1 and S2 Freq. Indication
W S2 Stable Time Delay
YEN Bypass T and W Time Delays
*Available with Delayed Transition switches only.
OPTIONAL PACKAGES
Exerciser (MEXE) Package, includes:
● STDS Functions
● A1/A1E – S1/S2 Failure aux contact
● A3/A4 – One additional contact each
● CDP – Programmable exerciser
● Q2 – Remote Peak Shave/Load Test
● R16 – Phase Rotation Sensing
Controls (MCON) Package, includes:
● EXES Functions
● Q3 – Remote Inhibit transfer to Emergency
● Q7 – Inhibit Transfer to Normal
● T3/W3 – Elevator Pre-Signal Aux Contacts
● UMD – Universal Motor Load Disconnect
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Sensing (MSEN) Package, includes:
● EXES Functions
● Normal Source Over voltage sensing (3 phase)
● Q7 – Inhibit Transfer to Normal
● S12P – Auto/Manual Selector Switch
Special (MSPE) Package, includes:
● CONS Functions
● SENS Functions
● S5P – Manual transfer to Normal Switch
(Replaces S12P)
Switchgear (MPSG) Package, includes:
● SPES Functions
● Additional set of A3/A4 Contacts
● R15 – Load Shed to “Dead Normal” or
● R15D – Load Shed to Neutral Position*
● S12/P – Auto-Manual Selector Switch
Screenshot of ATS operating parameters on Cat
Switchgear HMI.
Combined with the optional Modbus
Communication Card, the PSGS package allows
for integration with Cat Switchgear. This feature
allows ATS operating parameters to be displayed
on the PowerLynx
optional Remote Monitoring Software. Supply of
this feature set affords real-time monitoring of the
ATS as well as direct control over the following
parameters from the Switchgear HMI:
● Timer Settings
● Pickup/Dropout settings
● Testing Functions
● Alarm functions
● Manual operation
4
®
3000 HMI as well as on the
AUTOMATIC TRANSFER SWITCH
CTS SERIES ACCESSORY DEFINITIONS
6P
Microprocessor activated test switch (Momentary)
6A
Hardwired test switch (Maintained)
6AP
Microprocessor activated test switch (Maintained)
6BK
Hardwired test switch (Maintained Auto – Momentary Test)
Key operated
6CK
Hardwired test switch (Maintained Auto – Maintained Test)
Key operated
A1
Auxiliary Contact S.P.D.T. – Normal (Source 1) Failure
A1E
Auxiliary Contact S.P.D.T. – Emergency (Source 2) Failure
A3
Auxiliary Contact – closed in emergency (Source 2) Additional
available (10 max.) on CTS Series and need to be specified
A4
Auxiliary Contact – closed in normal (Source 1) Additional
available (10 max.) on CTS Series and need to be specified
A62
Motor disconnect and staged restart (1 contact)
AB3
Auxiliary contact – closed in bypass emergency (Source 2)
(S.P.D.T.) (Standard up to 400A) Additional available (10 max.)
on CBTS Series and need to be specified
AB4
Auxiliary contact – closed in bypass emergency (Source 1)
(S.P.D.T.) (Standard up to 400A) Additional available (10 max.)
on CBTS Series and need to be specified
CALIBRATE
Microprocessor activated calibration feature
CDP
Programmable exerciser daily, 7/14/28/365 days
user-selectable, with or without load
CDT
Exerciser no load timer
CTAP
Chicago transfer alarm panel mounted in door of enclosure.
Includes 3 aux. contacts and fuse.
DS
Disconnect Switch. Disconnects source voltage to transfer
power panel.
DT (DELAYED TRANSITION ONLY)
Time Delay from Neutral Switch position to Source 2
on retransfer
DW (DELAYED TRANSITION ONLY)
Time Delay from Neutral Switch position to Source 2
on retransfer
E
Engine Start Relay
EL/P
Event log of last 16 events
ETHERNET
Ethernet Communication Adapter. Requires Modbus
Communication Module.
F
Fan contact, closed when engine runs.
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CT
CTS SERIES ACCESSORY GROUP MATRIX
CTS SERIES ACCESSORY DEFINITIONS
(continued)
HT(1)(2)
Heater and Thermostat 208/240V (1) 380/600V (2)
mounted and
inter-wired in enclosure. (requires larger enclosure for
40-200A)
K
Frequency Meter (Analog) – Door mounted
K/P
Frequency Indication on the controller
LNP
Center-off position LCD-Indicator
L1
LED light indicates Switch in Source 2 position
L2
LED light indicates Switch in Source 1 position
L3
LED light indicates Source 1 available
L4
LED light indicates Source 2 available
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AUTOMATIC TRANSFER SWITCH
CTS SERIES ACCESSORY DEFINITIONS (continued)
LonWorks
LonWorks Communication Module
M1
Single Phase Amp Meter (Analog)
M2
Three Phase Amp Meter (Analog)
M90
EPM2000 True RMS Digital Meter with display (Amps, Volts,
Power, Energy, Power Factor and Frequency). 3 Line LED
Display. 50/60 Hz Universal Operation. 1 or 3 phase. Standard
Modbus RTU RS485 communications capability.
M90A
Includes Modbus communication card and factory wiring
between EPM2000 and Modbus communication card.
M90B
Includes Modbus communication card, Ethernet communication
adapter and factory wiring between EPM2000 and Modbus
communication card.
M91
EPM6000 True RMS Digital Meter with display (Amps, Volts,
Power, Energy, Power Factor and Frequency, THD). Certified
energy and demand metering. Meets ANSI C12.20 and IEC
687 Accuracy Classes. Front IrDA Port Laptop Connection.
Standard Modbus RTU RS485 or DNP 3.0 communications
capability.
M91A
Includes Modbus communication card and factory wiring
between EPM6000 and Modbus communication card.
M91B
Includes Modbus communication card, Ethernet communication
adapter and factory wiring between EPM6000 and Modbus
communication card.
Modbus
Modbus RTU Communication Module
N1
Running Time Indicator – Door mounted
N2
Operation Counter – Door Mounted
P1
Engine Start Timer (adjustable to 6 seconds)
P2
Engine Start Timer – Extended time delay (adjustable to
300 seconds)
Q2
Peak shave/remote load test/area protection – Relay (S.P.D.T.)
(Need to specify voltage – 120 VAC, 24 VAC, 24 VDC – 120V
default standard)
Q3
Inhibit transfer to emergency (Source 2) (load add relay) – Relay
(S.P.D.T.) (Need to specify voltage – 120 VAC, 24 VAC,
24 VDC – 120V default standard)
Q7
Inhibit transfer to normal (Source 1) – Relay (S.P.D.T.) (Need to
specify voltage – 120 VAC, 24 VAC, 24 VDC – 120V default
standard)
R1-1/R1-3
Over Voltage sensing for normal (Source 1) single (R1-1)
or three (R1-3) phase
R15/R15D
Load Shed. Should Source 2 become overloaded, a signal can
be given to switch to the Neutral position.
R16
Phase rotation sensing of Normal (Source 1) and
Emergency (Source 2)
R26/R26D
Interruptible Power Rate Provisions. Allow transfer out
of Source 1 position to Mid position or dead Source 2.
Alarm and Pre-Signal circuit included. (Need to specify
voltage – 120 VAC, 24 VAC, 24 VDC
R50
In Phase monitor between Normal (Source 1) and
Emergency (Source 2) to allow transfer
S5P
Microprocessor activated auto/manual retransfer
selector switch for transferring to Normal (Source 1)
(includes microprocessor activated YN accessory)
S12P
Microprocessor activated auto/manual retransfer
selector switch for transferring to Normal (Source 1)
(includes microprocessor activated YN & YE accessory)
S13P
Microprocessor activated commit/no commit on
transferring to Emergency (Source 2) (with
enable/disable settings)
S14K
Keyed selector switch for retransfer to normal-test-auto
SW1
Auto/Off/Start Engine control selector – Door mounted
(keyed or non-keyed operation available)
SW2
Auto/Off Engine control selector – Door mounted
(keyed or non-keyed operation available)
SW3
Source Priority Selector Switch – Door mounted. Allows
selection of Source 1 or Source 2 to be the Prime
Source. Transfer Switch will transfer to selected Prime
Source if that Source is available. (keyed or non-keyed
operation available)
T
Retransfer to Normal (Source 1) adjustable time delay
T3/W3
Pre-signal contact on transfer to Normal (Source 1) or
Emergency (Source 2) during test
U
Engine stop /cool adjustable cool down timer
UMD
Pre and post transfer output adjustable time range.
Functions in both directions. Includes 2 circuits.
(Additional circuits available).
VI
Voltage imbalance between phases (3 Phase only)
W
Adjustable time delay on transfer to Emergency
(Source 2)
YEN
Bypass transfer timers function (soft key switch in
microprocessor)
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6
AUTOMATIC TRANSFER SWITCH
CTS SERIES DIMENSIONAL SPECIFICATIONS
CTS Series Transfer Switches
Ampere Height Width Depth Reference Application
Rating Poles (A) (B) (C) Figure Weight Notes
40,80, 100 & 150 2,3 24 (610) 18 (457) 11 (279) A 57 (26) 1-7
4 24 (610) 18 (457) 11 (279) A 60 (27)
225, 260 & 400 2,3 46 (1168) 24 (610) 14 (356) A 165 (75) 1-7
4 46 (1168) 24 (610) 14 (356) A 170 (68)
600 2,3 74 (1880) 40 (1016) 20 (508) B 380 (172) 1-8
4 74 (1880) 40 (1016) 20 (508) B 430 (195)
800, 1000 & 1200 2,3 74 (1880) 40 (1016) 20 (508) B 455 (206) 1-8
4 74 (1880) 40 (1016) 20 (508) B 540 (245)
1600 & 2000 3 90 (2286) 36 (914) 48 (1219) C 1010 (458) 1-8
4 90 (2286) 36 (914) 48 (1219) C 1160 (526)
3000 3 90 (2286) 36 (914) 48 (1219) C 1130 (513) 1-8
4 90 (2286) 36 (914) 48 (1219) C 1395 (633)
4000 3 90 (2286) 47 (1194) 62 (1575) C 1595 (723) 1-11
4 90 (2286) 47 (1194) 62 (1575) C 1850 (839)
Application Notes :
1. Dimensions are listed in inches (mm) and weights in pounds (kg).
2. Includes 1.25" door projection beyond base depth. Allow a minimum of 3" additional depth for projection of handle, light,
switches, pushbuttons, etc.
3. All dimensions and weights are approximate and subject to change without notice and are not for construction use.
4. Special enclosures (NEMA 3R, 4, 12, etc.) may include mounting tabs, etc. Consult the published dimension drawings for details.
5. Normal and emergency may be ordered inverted on any switch. The load may be inverted 500-1200 amps.
Consult the factory for details.
6. Special lug arrangements may require different enclosure dimensions. For certified drawings, contact Caterpillar.
7. Packing materials must be added to weights shown. Allow 15% additional weight for cartons, skids, crates, etc.
8. Add 4" in height for removable lifting lugs.
9. 4000 amp depth dimension shown is standard. Depending on your cable/conduit requirements you may desire a deeper
enclosure. Consult Caterpillar for further details.
10. Lug adapters for 3000-4000 amp limits may be staggered length for ease of entrance. Consult Caterpillar for details.
11. Ventilation louvers on side/rear of enclosure at 3000 and 4000A. One side or rear must be clear to afford proper airflow.
NEMA 1 Enclosed
LEHE4651-04
7
AUTOMATIC TRANSFER SWITCH
AL-CU UL LISTED SOLDERLESS SCREW-TYPE TERMINALS
FOR EXTERNAL POWER CONNECTIONS
Switch Size
Amps
40-80
100-225
260
400
600 2
NOTES:
* Line and load terminals are located in rear and arranged for bus bar connection.
1. Special terminal lugs and neutral bars are available at additional cost.
Contact factory and advise cable sizes and number of conductors per pole.
2. Fully rated solid neutral (3x standard normal power connector) provided when required by system voltage.
3. Normal and emergency may be ordered inverted on any switch. Load may be inverted 600-1200 amps.
Consult the factory for details.
4. Lug adapters for 3000-4000 amp units may be staggered length for ease of entrance. Consult the factory for details.
5. Special lug arrangements may require different enclosure dimensions. For certified drawings, contact Caterpillar
Normal, Emergency
& Load Terminals
Cables
per Pole
1
Range of Switch Size Cables
Wire Sizes Amps per Pole
#8 to 3/0 AWG 800/1000/1200
#6 AWG to 250 MCM
#6 AWG to 350 MCM
#4 AWG to 600 MCM
#2 AWG to 600 MCM
1600
2000
3000
4000
Normal, Emergency
& Load Terminals
4
8 600 MCM
Range of
Wire Sizes
#2 AWG to 600 MCM
Information contained in this publication may be considered confidential. Discretion is recommended when distributing.
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and product identity used herein, are trademarks of Caterpillar and may not be used without permission.
www.Cat-Electric
©2012 Caterpillar
Materials and specifications are subject to change without notice.
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All Rights Reserved.
Printed in U.S.A.
LEHE4651-04 (11/12)
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