CAT LEHE4651-04 User Manual

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

LEHE4651-04

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.

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

LEHE4651-04

3. Series CTSD: The CTSD offers a delayed

4. Series CTSCT: Cat closed transition

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.

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