Document ID: chunk:federal_register_of_legislation:F2023C00165:reg:6v:p4
Version: federal_register_of_legislation:F2023C00165
Segment Type: reg
Provision Reference: reg 6V (pt 4/19)
Character Range: 124551–127808

lateral deviation of filament centre from two mutually perpendicular planes both containing the reference axis and one containing the axis of the reference pin.
2/ The bulb of production lamps shall be amber. (See also note5/).
3/ To be checked by means of a box system, sheet PY21W/2.
    4/ For 24V heavy-duty lamps having a different filament shape, additional specifications are under consideration.
    5/ The bulb of standard filament lamps shall be amber or clear. For amber standard filament lamps, changes of the bulb temperature shall not affect the luminous flux which might impair photometric measurements of signalling devices. Moreover the colour shall be in the lower part of the tolerance area.
CATEGORY PY21W

Sheet PY21W/2

Screen projection requirements
This test is used to determine, by checking whether the filament is correctly positioned relative to the reference axis and the reference plane and has an axis perpendicular, within +/- 15 degrees , to the plane through the centre line of the reference pin and the reference axis, whether a filament lamp complies with the requirements.

Reference  a    b    h    k
Dimension  3.5  3.0  9.0  1.0

Test procedures and requirements.
     1.  The filament lamp is placed in a holder capable of being rotated about its axis and having either a calibrated scale or fixed stops corresponding to the angular displacement tolerance limits. The holder is then so rotated that an end view of the filament is seen on the screen on to which the image of the filament is projected. The end view of the filament shall be obtained within the angular displacements tolerance limits.
      2. Side elevation
    The filament lamp placed with the cap down, the reference axis vertical and the filament seen end-on, the projection of the filament shall lie entirely within a rectangle of height "a" and width "b", having its centre at the theoretical position of the centre of the filament.
    3.                  Front elevation
    The filament lamp placed with the cap down and the reference axis vertical, the filament lamp being viewed in a direction at right angles to the filament axis:

3.1 The projection of the filament shall lie entirely within a rectangle of height "a" and width "h", having its centre at the theoretical position of the centre of the filament.
3.2 The centre of the filament shall not be offset by more than distance "k" from the reference axis.

CATEGORY H6W

Sheet H6W
 The drawings are intended only to illustrate the essential dimensions of the filament lamp
Dimensions in mm

Dimensions in mm                                                  Filament lamps of   Standard
                                                                  normal production   filament

min.                                                              nom.                max.             lamp
e                                                                 14.25               15.0             15.75       15.0 +/- 0.25
Lateral deviation 1/                                                                                   0.75        0.4 max.
beta                                                              82.5                90               97.5        90 degrees +/-