This range of power supplies provides compact, reliable and efficient units meeting the requirements of 855501, parts 1,5 and 7 (Eexdi 1).  The units may also be used to power appropriate equipment certified for use with the power supplies complying with BS6182 (part 1 - dc supplies; part 2 - ac supplies).

Construction

The enclosure comprises two rugged but lightweight zinc pressure diecastings.  The larger of the castings has two compartments: an intrinsically safe (i.s.) chamber for the output terminals and a flameproof (FLP) chamber for the electrical components.  The wiring between these two clambers passes via an FLP bush.

The smaller of the two diecastings forms the cover of the FLP chamber, it has a round window through which a green 'mains on' indicator may be viewed.

The FLP path between the FLP chamber and its cover is formed by a tapered rectangular spigot on the cover and a corresponding tapered face on the chamber casting.  There is a nitrile rubber 'O' ring to seal the chamber against dust and damp.

The FLP paths and the inside of the enclosure are chromated and passivated.  All external surfaces are powder coat painted white.

Two FLP entries are provided at the left-hand side of the FLP chamber to take spigotted FLP glands.  Each unit is supplied without FLP glands but includes one brass FLP blanking flange.  The i.s. terminal chamber has facilities for six gland entries, all threaded CM20.

Certification and Approval

These power supplies have certification to BS5501.  They may also be used to power equipment certified to BS1259.  These supplies have been approved under the British Coal Electrical Acceptance Scheme.