PD IEC TR 60887 pdf download

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 the glass bulbs used as envelopes for electric lamps. The application of such designations is directed towards the descriptions of finished lamps.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
bulb
outer envelope of glass or other transparent or translucent material enclosing the essential components of an electric lamp
2.2
approximate reference line
construction line transverse to the axis through the neck of the bulb defining the approximate position at which the rim of a cap, such as an Edison screw cap, would meet the neck of a bulb
NOTE The sole purpose of the approximate reference line is to aid the establishment of technical definitions of bulb shapes. This line appears in Figures 1 and 2 as a C-D line. No such line exists for pressed glass bulbs .
3 Basic components of a designation
3.1 General
Glass bulbs should be described by a designation consisting of a sequence of letter and number 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 in other 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 be discouraged and preference given to millimetre units.
3.2 Rectangular bulbs Rectangular glass bulbs should be described by the letter symbol REC followed by two sets of numbers. The first number should designate the dimension of the shorter side; the second number should designate the dimension of the longer side. These numbers should be separated by the multiplication symbol (×). The dimensions should be in millimetres.
4 Bulb shape classification
4.1 Basic shapes
The basic shape symbols are listed below. The following descriptive information used in conjunction with the associated illustration in Figure 1 forms the definition of each shape.
4.2 Modifiers
The basic shape designations in Subclause 4.1 may be modified by the addition, as a suffix, of one of the modifier symbols listed below. The following descriptive information used in conjunction with the associated illustration in Figure 2 forms the definition of each shape.