1.1 General
Protective relays, although generally of robust construction, require careful
treatment prior to installation and a wise selection of site. By observing a few
simple rules the possibility of premature failure is eliminated and a high
degree of performance can be expected.
The relays are either despatched individually or as part of a panel/rack
mounted assembly in cartons specifically designed to protect them from
damage.
Relays should be examined immediately they are received to ensure that
no damage has been sustained in transit. If damage due to rough
handling is evident, a claim should be made immediately to the transport
company concerned and the nearest General Electric representative should be
promptly notified. Relays which are supplied unmounted and not intended for
immediate installation should be returned to their protective polythene bags.
1.2 Unpacking
Care must be taken when unpacking and installing the relays so that none
of the parts are damaged or their settings altered and must at all times be
handled by skilled persons only.
Relays should be examined for any wedges, clamps, or rubber bands
necessary to secure m
oving parts to prevent damage during transit and these
should be removed after installation and before commissioning.
Relays which have been removed from their cases should not be left in
situations where they are exposed to dust or damp. This particularly
applies to installations which are being carried out at the same time as
constructional work.
1.3 Storage
If relays are not installed immediately upon receipt they should be stored in a
place free from dust and moisture in their original cartons and where de-
humidifier bags have been included in the packing they should be retained.
The action of the de-humidifier crystals will be impaired if the bag has been
exposed to damp ambient conditions and may be restored by gently heating
the bag for about an hour, prior to replacing it in the carton.
Dust which collects on a carton may, on subsequent unpacking, find its way
into the relay; in damp conditions the carton and packing may become
impregnated with moisture and the de-humidifying agent will lose its efficiency.
The storage temperature range is –25° and +70°C.
1.4 Site
The installation should be clean, dry and reasonably free from dust and
excessive vibration. The site should preferably be well illuminated to facilitate
inspection.
An outline diagram is normally supplied showing panel cut-outs and hole
centres. For individually mounted relays these dimensions will also be found in
Publication R6008.
Publication R7012 is a Parts Catalogue and Assembly Instructions. This
document will be useful when individual relays are to be assembled as a
composite rack or panel mounted assembly.
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