Overview: The S&C Micro-AT™ Source-Transfer Controls are designed for use in S&C Metal-Enclosed Switchgear and Source-Transfer Pad-Mounted Gear. They work with power-operated S&C Mini-Rupter® and Alduti-Rupter® Switches to provide automatic source transfer for systems rated up to 34.5 kV, ensuring critical-load continuity by minimizing interruptions.

Features: The control uses an advanced microprocessor for operations, with settings entered via a keypad. It includes menus for configuring operating characteristics and parameters, protected by access codes. Diagnostic tools record system status during operations, and events are indicated by a lamp on the 'EVENT' menu key.

Solid-State Circuitry: The device features reliable solid-state electronics with metal-oxide surge protectors. It undergoes rigorous testing, including ANSI Surge Withstand Capability Test and a severe capacitive-discharge test, ensuring durability against voltage surges.

System Applications:

• Common-Bus Primary-Selective Systems: The control monitors power sources and initiates automatic switching when preferred-source voltage is lost. It supports automatic or manual return to normal configuration, with options for open or closed transition retransfer.
• Split-Bus Primary-Selective Systems: The bus is divided into sections, each with its source. The control manages automatic switching when voltage is lost, with similar return options as the common-bus system.

Voltage Sensing: The control accommodates various voltage-sensing schemes for single-phase and three-phase systems, with options for calibration and normalization to compensate for unbalance.

Unbalance Detection: This feature protects against source-side open-phase conditions by monitoring negative-sequence voltage, initiating transfer if unbalance exceeds a preset level.

Overcurrent Lockout: Prevents automatic transfer into a fault by setting up a lockout circuit if overcurrent exceeds a preset level. The lockout mode can be externally reset.

Additional Features:

• Supervisory Control: Allows remote switch operation with appropriate control wiring.
• Remote Indication: Permits remote monitoring of source voltages and system status.
• Test Panel: Optionally available for testing the source-transfer scheme and related features.