Description

The 1831Y Dowmic Switch used on many British Aircraft operate efficiently at altitudes up to 60,000 ft and in ambient temperatures from -40ºC to +70º (-65ºC to +150ºC for special applications).

These units are fitted with oil-resistant synthetic-rubber button shrouds and terminal grommets, which provide immunity from normal weather conditions. For extreme operations where free water may be present ‘weather-sealed’ Dowmics are available on which the grommet sealing is supplemented by adhesive compounds. For extreme temperatures applications silicone rubbers are used.

The switch rocker carries two moving contact blades together with a soft iron armature, which moves between two permanent magnets to give a positive ‘snap’ action. A unique feature of this design is that contact pressure increases up to the point of break, reducing the possibility of ‘arcing’.

The Dowmic Switch can be obtained with socket-type terminals for use with standard 4 and 7 amp SBAC Ferrules, or alternatively with 6BA screw-type terminals. To facilitate installation a schematic wiring diagram is shown on the switch case and a range of cable grommets is available to suit individual requirements.

A similar Dowmic Switch type 4004 is available for industrial applications. A conduit adapter type 1265K can be supplied for direct connection into protected wiring systems.

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Specification

Design specification: DE No 1
Type of case: One piece light alloy
Weight: 121gm
Mounting Attitude: Un-resricted
Over Travel: 12.7mm (7.3mm for type 4004)
Safe Overload: 680kg
Temp Range: -40ºC to +70ºC
Rating (per contact set) 240v.AC 50Hz - 5amps resistive (4004), 120v.DC - 1amp resistive, 30v.DC - 8amps resistive, - 5amps 0.15H Inductance
Pre Travel: 2.16mm maximum
Differential: 0.51mm maximum
Over Travel: 12.7mm (7.3mm for type 4004)
Operating Load: 2.09 to 4.41kg maximum