Circuit Protection

Eaton Moulded Case Navy circuit breakers (AQB) provide both overload protection for conductors and short circuit protection for all circuit elements such as conductors, motors and starters. They also serve as a means for manual disconnect. All Navy Circuit Breakers also meet applicable specifications for "hi-shock." These manually operated, AC and DC, 60 and 400 hertz breakers, are rated from 5 to 4,000 amperes with interrupting ratings from 1,500 to 150,000 amperes.

What's New
Product Guide PG01218003E released January 2010

Eaton is introducing the new Electronic Trip 250 amp frame Navy Breakers, the AQB-A253 and AQB-L253. The L253 is another Current Limiting Navy Breaker, offering 100KA interrupt ratings without the fuses associated with LF250 or LF252 breakers. Only Eaton manufactures Current Limiting Navy Breakers.

Specific Navy Features
Navy circuit breakers retain all the features of standard commercial type AB De-ion breakers. Built to Navy specifications, they incorporate the following Navy requirements:

Shock Resistant Moulded Case - Housing consists of rear base section and cover moulded of glass alkyd material. This material, reinforced glass filled thermosetting plastic, has very high mechanical strength (shock and impact resistance), is both fire and moisture-resistant and provides excellent dielectric characteristics.

Anti-Shock Device - Inertia weight over center pole holds trip bar in latched position under shock conditions but does not prevent thermal or magnetic trip units from functioning on overload and short circuits.

Vibration Qualified - All Navy breakers are vibration hardened.

EMI Qualified - All electronic trip units must pass electro-magnetic interference tests.

Calibrated for 50°C - All Navy breakers are calibrated for shipboard installation at 50° C ambient.

Interchangeable Trip Units - All thermal and magnetic trip units in AQB circuit breakers are encased in sealed, self-contained units that are interchangeable with other trip units of different ampere ratings within the same frame size.

Plug-in Connectors - All AQB breakers are designed for easy plug-in installation. Plug-in type connectors are built into the base of the breaker for use with moulded mounting blocks complete with studs. For front connection, pressure-type cable terminals are used instead of plug-in connectors. ALB breakers have a clamp terminal on the line end to receive panelboard bus stab projections.


Standard Design Features

Corrosion-Resistant - All parts are specially treated to resist corrosion. Fungus-moisture resistant treatments for severe atmospheres are available as modifications.

Positive Position Indication - Position of handle always indicates ON, OFF, or TRIPPED.

Free Bearing Surfaces - Dissimilar metals are used to prevent bearing wear and eliminate sticking.

De-ion Arc Quenchers - This Eaton development consists of a series of grid plates mounted in parallel between supports of insulating material. The slots in the steel plates are directly over the contacts and draw the arc from the moving contact up into the divided chamber where it is confined, divided, and extinguished.

Silver Alloy Contacts - Special silver alloy contacts prevent sticking and welding, increase contact life and insure low resistance when carrying full-rated load.

Quick-Make, Quick-Break Over Center Toggle Mechanism - Provides quick, positive action in opening and closing of circuits, prevents "teasing" of contacts and reduces contact wear.

Complete Interpole Barriers - Insure against internal flashovers when faults occur.

Common Trip - Two and three-pole units have insulated common trip bar that opens all poles simultaneously when an overload occurs on any one, thus eliminating possibility of single-phasing.

Tested Accuracy - All tripping members have ground and polished latch surfaces heat treated to prevent galling or later distortion. All parts are tested in temperature-controlled atmosphere to assure correct calibration and perfect mating. Each breaker is thoroughly tested.

Factory Sealed - Smaller breakers are factory sealed to prevent tampering with calibration. Interchangeable trip units are individually sealed.


Additional Information
Navy and Marine circuit breakers are sold through our network of distributors. To find your nearest Eaton circuit breaker distributor, click on the "Find Us" link located at the top of the page.

For more information about Eaton Navy Breakers, please contact our Technical Resource Center at 1-800-356-1243.