PD IEC TR 60887 pdf download – Glass bulb designation system for lamps

PD IEC TR 60887 pdf download – Glass bulb designation system for lamps

PD IEC TR 60887 pdf download – Glass bulb designation system for lamps
1 Scope
This technical report describes a system of nomenclature that provides designations of theglass bulbs used as envelopes for electric lamps. The application of such designations isdirected towards the descriptions of finished lamps.
2Terms and definitions
For the purposes of this document, the following terms and definitions apply.
outer envelope of glass or other transparent or translucent material enclosing the essentialcomponents of an electric lamp
approximate reference line
construction line transverse to the axis through the neck of the bulb defining the approximateposition at which the rim of a cap,such as an Edison screw cap, would meet the neck of abulb
NOTE The sole purpose of the approximate reference line is to aid the establishment of technical definitions ofbulb shapes.This line appears in Figures 1 and 2 as a C-D line.No such line exists for pressed glass bulbs.
3Basic components of a designation
Glass bulbs should be described by a designation consisting of a sequence of letter andnumber symbols without spaces, as follows:
a) a letter symbol consisting of up to three letters which describes the bulb shape.The letter
or letters of this symbol may in some cases be a basic shape letter symbol only and inother cases it may be a combination of a basic shape symbol and a modifier or modifiers.Basic shapes, modifiers and special shapes are defined in Clause 4;
b) a number symbol which states the major diameter (nominal) of the bulb, in millimetres.
NOTE In some countries, bulb diameter has been stated in multiples of 1/8 of an inch. This practice should bediscouraged and preference given to millimetre units.
3.2Rectangular bulbs
Rectangular glass bulbs should be described by the letter symbol REC followed by two sets ofnumbers. The first number should designate the dimension of the shorter side; the secondnumber should designate the dimension of the longer side. These numbers should beseparated by the multiplication symbol (x).The dimensions should be in millimetres.
4.1 Basic shapes
The basic shape symbols are listed below. The following descriptive information used inconjunction with the associated illustration in Figure 1 forms the definition of each shape.
Lefter symbolGeneral meaning
xplanatory notes
bulb shape having a spherical end sectionthat is joined to the neck by a radius thata) has a centre outside the bulb,
b) has a magnitude greater than the radius of
the spherical section,
c) and is tangent to both the neck and the
curve of the spherical end section.
NOTE These bulbs do not have any significant straightportion between the spherical end and the transitionalradius into the neck.
bulb in which the curve making up the majorportion of the side of the bulb has a radiusgreater than one-half the bulb diameter and acentre in the plane of the maximum diameter.This designation also applies when two radiiare used. one for the lower part and a largerone for the upper part (candle type).
bulb consisting of a conical or near-conicalend section,which is joined to the neck by anapproximately hemispherical section; if the endsection is nof conical, the curve making up themajor portion of the side of the bulb has a
centre below the plane of the maximumdiameter.
bulb similar to a “B” shape but having thesides formed by a section of an ellipse.
bulb resembling the flame of a candle havingirregular flutes on the sides.
bulb of essentially spherical shape.
A bulb which is similar in shape to an “M” bulb,except there is a conical transitional sectionbetween the major diameter and the neckrather than a curved section.
bulb having a spherically shaped end sectionblended, above the major diameter, to a
smaller radius curve centered on the majordiameter. which blends with a transition curveof approximately the same radius for joiningthe neck.