12. Answers to the Questions for Repetition and Knowledge Tests

Cp. Section 1

1. The lighting installations include: lighting fittings, light sources, accessories for both, if required. The installation wiring consists of plastic cables, electric lines with appertaining connection material, switching devices, junction boxes, etc. Reflecting surfaces are included in the design of the installation.

2. The light colour with its specific colour temperature, the design of the lighting fittings and an aesthetic installation reach the emotions of man. With the help of coloured light, for example, one can give or spoil a person’s appetite or stimulate or restrain the desire for communication. Light can exercise a decisive influence on the labour productivity.

Cp. Section 2

1. This designation stands for the real light power of a light source. The indication of electric power in watt used hitherto allows no accurate statement on the actual light power or efficiency.

2. The efficiency factor of illumination consists of the illuminator efficiency and the room utilization factor. The efficiency of a fitting indicates in per cent how much light emitted by the light source is absorbed by the fitting. The room utilization factor comprises the ceiling and wall reflections as well as the room conditions and proportions.

3. Colour temperature, light intensity, absence of glare, richness in contrasts, shadowyness.

Cp. Section 3

1. Indoor lighting: For general lighting with uniform illumination on the measuring level the luminous flux or efficiency method is sufficient. For local lighting the light intensity method can be applied with rotational symmetrical lighting fittings. Outdoor lighting: Illumination method.

2. The shielded or unshielded light source shows different deposition of dust. Getting dusty leads to the reduction of the yield of luminous flux. Direct or indirect lighting is different in irradiation as to the visual object.

An extremely unfavourable variant would be an indirect illumination with a dirty-grey ceiling.

3. It informs about the emission capacity of the lighting fitting under various angles. It is related to a luminous flux of 1000 lm and must be expressed in terms of the respective light source power.

4. According to a grid system, the illuminations in a room are measured or calculated and the results entered in the crossings of the grid system. If the various points are connected, a mountain-like figure appears.

Cp. Section 4

1. On the basis of selenium photo-cells.

2. Illumination measuring, luminance measuring.

Cp. Section 5

3. By starter, timer switch (1 to 4 seconds), electronical starter, electronical start and serve unit. By ignition strip at the lamp tube and quick-start switching, also with single-pin cap.

4. Separate switching (classic method), tandem switching (two lamps - one series reactor), dual lamp circuit (two lamps - two series reactors but one capacitive branch and one inductive branch).

5. It serves to provide a sufficiently high ignition voltage during the ignition process and to limit the current during operation.

6. Best penetration of fog and mist, long effective burning life, use in outdoor lighting installations possible without problems.

7. Quartz glass bulb (burner) with enclosed auxiliary and main electrodes.

Framework with ignition current-limiting resistors, evacuated internal space.

External bulb clear or coated, mushroom-shaped or ellipsoidal. Base - Edison screw.

8. Almost independent of ambient temperature and therefore ideal for outdoor lighting installations.

Long service life; great light output.

A disadvantage is the great sensitivity to mains voltages or network failure for split seconds; long starting time and very long reclosing time after mains disconnection.

9. The lamp does not get enough voltage.

10. Polycrystalline alumina tube (discharge tube) with enclosed electrodes. It contains sodium, mercury and inert gas. The space between discharge tube and external bulb is evacuated Socked E 40.

Cp. Section 6

1. Firstly, by the unmistakable form, the size and the weight resulting therefrom.

Secondly, by its purpose of use.

The series reactor of the fluorescent lamp shall supply a high ignition voltage and, in addition, shall serve for current limitation.

The series reactor of the high-pressure mercury vapour lamp serves for current limitation only.

2. Discharge lamp circuits - due to the series reactors - are inductive consumers. The legislator demands the farest possible relief of the net from reactive current. Capacitors serve for accumulating inductive reactive current. Now, the wattless power required for the switching can - after having been released by the coil of the series reactor - be stored in the capacitor to a great extent. The net must no longer transport this power.

Cp. Section 8

1. They serve the technical purpose to accommodate the light sources, to bundle their light, to direct it or to disperse it. At the same time, they shall produce an emotional effect. Used in the right way, they help to save valuable electric energy.

2. Fittings for general lighting (indoor)

Local lamps

Fittings protected against fire-damp and explosion

Outdoor lighting fittings

Street lighting fixtures

Outdoor lighting fittings for decoration purposes

Floodlights and spot-lights

Domestic lighting fittings and those for decoration

Special lighting fittings.

3. Little energy consumption with a maximum light output.

Little space requirement, adjustable.

Decorative design, easy maintenance.

Mobile, easy to operate.

Cp. Section 9

1. Light advertisement using high-voltage luminescent tubes and high-voltage fluorescent tubes.

2. Leak transformers are used.

There are two circuit variants:

1. Supply of a writing by a transformer.
2. Supply of a writing by letter transformers.

3. Flashing switchings over controller drums.

Program switchings over controller drums.

Running writing

Swelling-light installations over actuating mechanisms.

Cp. Section 10

1. Physical, chemical, climatic, technical and aesthetic conditions.

2. Heat accumulation has to be avoided! Mounting at or on easily inflammable materials is not allowed.

With use of spot-lights or floodlights, the focal point which is situated away from the fittings must not be brought near inflammable materials.

When suspending the fittings, their weight must be carefully considered.

3. By combining general lighting installations with local lamps. The chief stress is put on the local (working place) lamps.

4. In places where colours are part of the visual task, for instance with colour patterns, light sources must be used which do not falsify the colours. Mixed light has proved good.

Cp. Section 11

1. Lighting installations need regular cleaning of the lighting fittings and light sources as well as timely replacement of used up lamps and defective accessories in order to maintain their efficiency. The expenditure of time and material increases, if the lamp are not replaced in due course.

2. There are schedules for this purpose. Mainly, planned stoppage times are used for maintenance of the lighting installation.

3. Lifting platforms, step-ladders, derrick wagons.

4. Light sources are replaced at definite intervals.

A three-years rhythm has proved good. Independent of the condition of the lamps, all lamps are replaced by new ones.

By this, the illumination level is raised and the energy consumption reduced, simultaneously.