CAT LEHE4651-04 manual Neutral Switching, Safe Manual Operation, CTS Series ATS

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

CTS SERIES ATS

400 amp, 2 pole

3.Series CTSD: The CTSD offers a delayed 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.

4.Series CTSCT: Cat closed transition 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.