Attachment_J.1.2_Automatic_Transfer_Switch_(ATS)_Specification.docx

Attachment J.1.2 Automatic Transfer Switch (ATS) Specification Attachment J.1.2 Automatic Transfer Switch (ATS) Specification

Overseas Building Operations

CFSM/FAC/PS

AUTOMATIC TRANSFER SWITCH

a. Provide equipment listed as requested in the Request for Proposal (RFP).

1.2 SUBMITTALS

Submit the following in electronic (PDF) format:

SD-02 Shop Drawings Connection Diagrams Fabrication Drawings Installation Drawings SD-03 Product Data Equipment and Performance Data Contacts Indicating Lights Terminal Board Enclosures Accessories SD-06 Test Reports Qualification Testing Operation Tests SD-07 Certificates Listing of Product Installations SD-08 Manufacturer's Instructions Automatic Transfer Switch

1.3 QUALIFICATION TESTING

Provide certified independent laboratory test data for the furnished unit or an identical unit. Ensure tests meet the general use requirements of UL 508, Table 22.1. Subject the complete automatic transfer switch to a test as outlined in NEMA ICS 1, paragraph 109.5. One cycle of operation tests under the UL 508 test requirements consists of a transfer of load from the normal source to the emergency source and reverse transfer to the normal source. After the required number of test cycles, ensure the temperature rise of the contacts has not exceeded 149 degrees F. Test the switch operating time and the sense relay pickup and dropout times.

Provide a complete automatic transfer switch system for use with engine-generator sets for standby power. Submit the following:

a. Connection diagrams showing the relations and connections of contacts, indicating lights, and terminal board by showing the general physical layout of all controls, the interconnection of one system (or portion of system) with another.

b. Fabrication drawings for contacts, indicating lights, terminal board enclosures, and accessories consisting of fabrication and assembly details to be performed in the factory.

c. Installation drawings for automatic transfer equipment.

d. Equipment and performance data for automatic transfer equipment including test information, system functional flows, safety features, and mechanical automated details.

2.1.1 Design Requirements

Unless otherwise directed provide an automatic transfer switch of the four-pole type for three-phase application or three-pole for single phase applications based on the requests within the RFP. Provision for switched neutral pole will be included as a standard configuration.

2.1.2 Performance Requirements

Provide an industrial quality automatic transfer switch capable of transferring the load from the normal power source to emergency power source, and from an emergency source to the normal power source. Provide a switch that is solenoid-operated, mechanically held, double-throw, rated for continuous duty, capable of transferring in 100 milliseconds or less, and conforming to the applicable requirements of UL 1008 and NFPA 70, Article 700, except as herein modified.

Ensure the automatic transfer switch is capable of being placed in either the normal or the emergency position. Transfer switches are expected to incur frequent transitions between utility and generator power; potentially four times each day and seven days a week indefinitely. As such, there is a need to withstand operations where 10,000 or more transfer cycles can be expected during the lifecycle of the switch.

Provide switch with short-circuit current rating of 30,000. Ensure switch is capable of withstanding 30,000 amperes for a period of 2 seconds without damage.

2.2.2 Self-Test Capability

Provide an automatic transfer switch with a control-circuit self-test feature capable of verifying the proper operation of the switch control circuit without moving the main contactor or causing discontinuity of service to the load. Include the following characteristics in the self-test circuit:

a. A key-operated switch that disconnects the main actuator and connects in its place, an indicator light. Design the key-operated switch to prevent removal of the key while the switch is in the self-test mode.

b. A power-failure simulator switch that removes voltage from the voltage-sensing devices so that emergency power activates the test light.

2.2.3 Enclosures

Provide automatic transfer switch enclosures with solid, unventilated, NEMA 4X, with manufacturer's standard finish.

The switch shall insure an open transition operation and that at no time during the transition shall generator and utility power coexist on a common bus. Provide main contacts with wiping-action silver alloy that when rated for operation at 50 amperes or greater are protected against arcing. Ensure auxiliary contacts and control transfer relay contacts have a minimum continuous current rating of not less than 10-amperes inductive at 120 volts ac. Provide the following auxiliary contacts:

a. Generator-control contacts, normally open, that close on under voltage or loss of normal power as specified, remaining closed until transfer back to normal power

b. Emergency-position contacts, normally open when the switch is in the normal position, that close when the switch is in the emergency position

c. Normal position contacts, normally closed when the switch is in the normal position, that open when the switch is in the emergency position Use two pole auxiliary contacts.

2.3.2 Indicating Lights

Furnish automatic transfer switch with two indicating lamps. Provide one light to indicate that the switch is operating on normal power and the other light to indicate that the switch is operating on emergency power. Fuse each indicating circuit.

2.3.3 Terminal Board

Internally wire control devices, indicating lights, auxiliary contacts, and internal control devices or auxiliary switches to a common output terminal board. Wire the internal functions to facilitate remote connections or monitoring.

2.4 OPERATION

Monitor normal source voltage across phase lines by sensing devices. If the normal source voltage in phase drops to 90 percent or less for a timed period, the automatic transfer switch starts the emergency source and transfer the load to the emergency source when voltage and frequency reach rated values or, if the emergency source is on, verify voltage and frequency of the alternate source and transfer the load to the alternate source through an open transition process. Field adjustment shall be possible for a time period between 1 to 30 seconds. Provide a voltage and frequency sensor relay to monitor rated values on the emergency side to prohibit transfer until the emergency source voltage and frequency reach at least 95 percent of the required rating. Provide phase failure protection, with 65 to 70 percent drop and 92 to 95 percent voltage pickup ratings.

Furnish the automatic transfer switch with a time-delay feature, field adjustable from 2 to 30 minutes that operates to delay automatic transfer back to normal power until the normal source voltage and frequency reach at least 95 percent of the rated voltage. However, if the emergency power fails, and the normal source is again available at 90 percent of the rated voltage, bypass the time-delay circuitry, and the load immediately transferred back to the normal source. Provide capability for manual transfer in either direction. Operate sensing relays without contact chatter or false response during voltage variations between dropout and pickup.

2.5 ACCESSORIES

Incorporate with the automatic transfer switch a 24-volt solid-state, high-and low-rate charger complete with rheostat and ammeter, to maintain the engine-generator cranking batteries in a fully charged condition.

Incorporate an engine-generator exerciser timer with the automatic transfer switch to permit weekly programming of engine-generator set test runs under load.

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