CIRCUIT SELECTOR SWITCH
FAA Type: L-847

Certified to:
FAA AC 150/5345-5A, ICAO Annex 14, and ETL

Product Highlights:
The Honeywell Circuit Selector Switch is designed to switch the output of a 6.6 A or 20.0 A Constant Current Regulator (CCR) to a total of four independent series lighting loops. It can be used with local or remote control systems. When the L-847 is switched off from local or remote control, the airfield lighting circuit is automatically disconnected and the CCR output is short-circuited.

General
• Easy installation and operation.
• Up to 4 circuit selectors in one unit.
• Operate from local or remote locations.

Safety
• Enclosure can be padlocked.
•Polycarbonate safety barrier.

Electrical
• Rated for 5,000 volts, 6.6 A and 20.0 A.
• Suitable for Rating 1 or 2 regulators.
• Optional supply of 24 V dc or 48 V dc.
• Standard supply of 120 V ac, +/- 10%, 60 Hz.
• Vacuum relays for long life and reliability.
• Vacuum relays rated for maximum 30.0 A.

Environmental
• Relative humidity levels up to 100%.
• Altitude rating from sea level to 3,000 m.
• Temperature rating from -55 to +55 °C.
• Enclosures rated NEMA 12 indoors (Class A) and NEMA 4 outdoors (Class B).

Operation
All L-847 circuit selector switches are identical. They are mounted on a modular sub-panel for ease of replacement and maintenance access. A complete selector switch includes two vacuum high-voltage relays and a solid-state time delay relay. High voltage insulators are included for connection of line and load power conductors.

The circuit selector switch operates with a make-before-break feature. To separate vacuum relays are used, K1A and K1B. K1B has a single contact, and is used to short the supply power from the regulator. K1A has two contacts, and is used to connect the regulator power to the field circuit. Relay K1B is always shorted before K1A is opened or closed. This protects the regulator and the field circuit from any interruptions while switching on or off.