ASCO Low Voltage Automatic Transfer Switch Systems

ASCO Low Voltage Automatic Transfer Switch Systems are suitable for transferring power from an available source to a critical load in emergency, peak and prime power applications. Telecommunications systems, data networks, industrial processes and critical installations demand proven emergency and standby power transfer solutions. As the world leader in emergency and standby power, ASCO products and systems safeguard your business and keep the power on.

ASCO Low Voltage Automatic Transfer Switch Systems include;

• Service Entrance Rated Transfer System
• ATS Switchboards
• Two Source Automatic Transfer System
• Three Source Automatic Transfer System
• Three Source Priority System

Service Entrance Rated Transfer System

ASCO service entrance rated transfer systems are designed for automatic switching of loads between the utility source and an alternate source of power. The transfer system also contains a disconnect device on the normal source, plus a disconnect link on the utility neutral, and a disconnect link between neutral and ground. If the utility source is Y connected, the voltage is greater than 250 volts phase to neutral and the system continuous current is greater than 1000 amperes, the utility disconnect device will be equipped
with ground fault trip.

Service Entrance Rated Transfer System Features

• The utility disconnect device will be equipped with ground fault trip if the voltage between neutral and ground is greater than 250 volts, and the continuous current is greater than 1000 amperes.
• Disconnect link for the utility neutral bus.
• Disconnect link between the neutral bus and the ground bus.
• Meets all NEC requirements for service entrance rating, and is labeled to UL 891 standards.
• Available up through 4000 amperes using ASCO 940, 962, 434, 436 and ASCO’s 7000 Series automatic transfer switches.

ASCO ATS Switchboards

ASCO ATS Switchboards (automatic transfer) is a switchboard containing two or more automatic transfer switches in a common line-up. The picture to the right shows two ASCO 962, 2000 ampere, automatic transfer bypass-isolation switches with circuit breakers on the normal and load side of each switch. An ammeter and voltmeter are also located on the load side of each switch.

ASCO ATS Switchboards Features

• Connects multiple automatic transfer switches together in a common switchboard
• Optional normal and/or emergency circuit breakers for overcurrent protection
• Optional distribution circuit breakers of the size and type to meet customer load requirements
• Optional instrument meters for normal, emergency, or load for local monitoring
• Designs can be provided with a UL 891 Label containing up through a 10,000 ampere main bus
• Utilizes ASCO 940, 962, 434, 436 and ASCO’s 7000 Series automatic transfer switches

Two Source Automatic Transfer System

ASCO two-source systems are designed for automatic switching of loads between the utility source and an alternate source of power. Upon the loss of the utility power source, the system provides an automatic start signal to the alternate source of power. Once the alternate source has reached proper voltage and frequency, the system transfers the critical load from the utility source to the alternate power source. When normal power is restored the controls will retransfer the load to the utility and signal shutdown of the alternate power source after allowing a cooldown period.

ASCO two-source systems include an automatic transfer switch, plus any or all of the following options; automatic engine starting controls, overcurrent protection for both
emergency and normal sources, instrument meters, status annunciation, and audible alarm. The systems are designed to NEMA switchboard construction and are labeled to UL 891 standards. These systems can be designed for top cable entrance, bottom cable entrance or bus duct connections.

Two Source Automatic Transfer System Features

• Normal, emergency, and/or load circuit breakers.
• Protective relaying (as required).
• Optional instrument meters for normal, emergency, or load for local monitoring.
• Designs are based on NEMA and UL 891 standards.
• Optional engine start control logic and/or load control logic.
• Designs available up to 4000 amperes utilizing ASCO 940, 962, 434, 436 and ASCO’s 7000 Series automatic transfer switches.

Three Source Automatic Transfer System

ASCO three-source systems are similar to ASCO two source systems except that a second alternate power source is added to back up the first if that power source fails. Upon the loss of the utility power source, the system provides all necessary controls to start both alternate power sources. The critical loads are automatically transferred to the first alternate power source that achieves acceptable voltage and frequency. The second alternate power source is then automatically shutdown after a time delay and cooldown period. If the first alternate power source fails, the second alternative power source will be automatically re-started and the load will be transferred from the first alternative power source to the second alternative power source. When the normal power is restored, the controls automatically retransfer the load to the utility power source.

Three Source Automatic Transfer System Features

• Control logic for selecting between the alternative power sources.
• Normal, emergency, and/or load circuit breakers.
• Protective relaying (as required).
• Optional instrument meters for normal, emergency, or load for local monitoring.
• Designs are based on NEMA and UL 891 standards.
• Optional engine start control logic and/or load control logic.
• Designs available up to 4000 amperes utilizing ASCO 940, 962, 434, 436 and ASCO’s 7000 Series automatic transfer switches.

Three Source Priority System

ASCO three-source priority systems are similar to the ASCO three-source systems except they protect two critical loads rather than one critical load. Upon the loss of the utility power source, the system provides all necessary controls to start both alternative power sources. The most critical load is transferred to the first alternate power source that achieves acceptable voltage and frequency. The second most critical load is then transferred to the second alternate power source when it achieves acceptable voltage and frequency. If the alternate power source feeding the most critical load should fail, the most critical load would be transferred to the second alternate power source and the second most critical load would be shed. When the utility power source is restored, the system controls automatically retransfer the loads to the utility and both alternate power sources are run for a cooldown period and then shutdown.

Three Source Priority System

• Control logic for selecting between alternate power sources.
• Normal, emergency, and/or load circuit breakers.
• Protective relaying (as required).
• Optional instrument meters for normal, emergency, or load for local monitoring.
• Designs are based on NEMA and UL 891 standards.
• Optional engine start control logic and/or load control logic.
• Designs available up through 4000 amperes utilizing ASCO 940, 962, 434, 436 and ASCO’s 7000 Series automatic transfer switches.