The Automatic Transfer Switch is a product that has evolved over decades in response to the changing needs of critical loads. When ASCO began developing this product, there were scarce applications and no standards. As a result, ASCO applied its good engineering judgment in defining the product to meet the need of customers who were becoming increasingly dependent upon the continuity of electric power to their critical loads. Factory floor and into the process industry.

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  Standard features in the 300 series Motor load transfer controls (inphase monitor) to keep motors operating during transfer. Pre-transfer & post-transfer load disconnect contacts for signaling motor starters, elevators, VFDs and other selected loads. Standard Engine Exerciser for weekly automatic testing of engine generator set with or without load. Selectable control switches for voltage, frequency, time delay settings & additional control features. Switch position lights, source availability lights, test switch and time delay bypass switch. Sizes 30 through 3000 amps in a compact design, 2, 3, & 4 pole configurations. Available 120 to 600VAC. UL 1008 listed to 480VAC for total system loads. True double-throw, inherently interlocked construction. Mechanically held, electrically operated utilizing a reliable, field-proven single solenoid operator. Contacts easily accessible for easy inspection and preventive maintenance. Meets National Electric Code requirements (U.S.). Rated for emergency and standby applications. Standard models in stock. Available in Type 1, 3R, 4 and 12 enclosures. Conversion kits available from stock to allow field addition of Optional Accessories.
  
  View ASCO 300 Series Specifications

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  ASCO 900 series Automatic Transfer Switches are suitable for emergency and standby power system applications. They meet emergency system rating requirements as defined in National Electrical Code (NEC) Article 700 and UL 1008. Also, they are suitable for the requirements of NEC Article 517 - Health Care Facilities, NEC Article 701 - Legally Required Standby Systems, NEC Article 702 - Optional Standby Systems, NFPA 99 Health Care Facilities, and NFPA 110 Emergency and Standby Power Systems. ASCO 940 Automatic Transfer Switches provide the most reliable means for transferring critical loads between two sources of electrical power (typically a utility and an on-site engine driven generator). Their quality design, rugged construction and proven performance assure maximum reliability and value for the specifying engineer, installer and user. The ASCO 940 consists of a power transfer switch and a microprocessor control panel, which is available in either open or enclosed configurations. The high withstand and close-on ratings achieved by the ASCO single-solenoid operator and unique contact design make ASCO 940s the best choice for all automatic transfer switch applications.
  
  (Word Document) View ASCO 900 Series Specifications

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  The 7000 Series is available in the conventional, two-position transfer configuration, plus closed or delayed transition modes of operation. Additionally, switched or overlapping neutral options provide for reliable operation of ground fault protection systems and reduction of voltage transients from unbalanced load switching. 7000 Series automatic transfer switches are available open or enclosed, with the largest selection of optional accessories offered anywhere. Conventional two-position transfer configuration, plus closed and delayed transition modes of operation. All configurations available with either automatic or non-automatic control. Qualified and listed to UL 1008 and CSA automatic transfer equipment standards. Independently qualified and listed to IEC 60947-6-1, CE and Kema Keur marked (optional). Rated up to 600 VAC, 30 through 4000 amperes. Reliable and field proven solenoid operating mechanism. Front replaceable main and arcing contacts (600-4000 amperes). Programmable microprocessor controller with keypad and LCD display. Centrally located terminal block for customer control connections (260-4000 amperes). Heavy-duty, 16mm, industrial grade control switches and indicating lights. Switch position indicators and true source acceptability lights.
  
  View ASCO 7000 Series Specifications