Incandescent halogen lamps. main parameters

 The rated voltage of halogen lighting lamps is divided into two groups - low (6, 12 or 24 V) or high (110-240 V). According to this division, a distinction is made between low voltage and mains voltage halogen lamps, respectively.

Special-purpose lamps are produced in a very wide range of operating voltages (from 3 V and more).

The power range practically corresponds to that of conventional incandescent lamps (from 1 to 5000-10000 W). Due to the gradual displacement of heat lamps from powerful floodlighting, leading manufacturers no longer offer lamps more powerful than 2000 watts for sale on the market.

The operating temperature and the amount of heat generated, which is the main product of heat emitters, are high. As a result, halogen lamps are water-sensitive and potentially flammable. In addition, the directly heated part of the lamp is usually located close to the place where the supply voltage is connected. This imposes special requirements on the material from which the sockets and lamps for these lamps are made. The characteristics of the lamps are independent of the ambient temperature.

The dimensions of low voltage halogen lamps can be safely called the minimum for heat sources of appropriate power. This is achieved by bringing the walls of the bulb as close as possible to the filament required to operate the halogen cycle. As for mains lamps, their dimensions depend on the design, and in most cases the length of the lamp is proportional to its power. The dimensions of lamps intended for direct replacement of incandescent lamps do not exceed the dimensions of their analogs.

Incandescent halogen lamps. What is the transition to low supply voltage for?

The transition to a low (up to 24 V) supply voltage can significantly reduce the resistance of the lamp filament to achieve the same electrical power. The length of the filament decreases, which means that it delays its own radiation to a lesser extent. Due to this effect, incandescent lamps designed for low voltages have a higher luminous efficiency than standard mains counterparts.

The above fully applies to halogen lamps. Already in the 1990s, the first samples of the so-called low-voltage models, or low-voltage halogen lamps, appeared. Similarly arranged lamps have been produced in the past, but they were mainly intended for film projection and other special applications.

The standard low voltage for powering halogen lamps is 12 V AC; direct current and / or ratings of 6 and 24 V are used somewhat less often. To obtain such voltages, special transformers (in slang called "halogen") are necessarily used.

Incandescent halogen lamps. Life extension and brightness control

To extend the service life of high-voltage GLN powered directly from the 220 V network, a simple device on a specialized microcircuit of the K1182PM1R phase regulator (KR1182PM1) will help.

The fact is that in the cold state the resistance of the lamp spiral is 10 times less than in the heated one. Therefore, the starting current of the GLN with a power of, for example, 100 W can reach 7 A. After the coil warms up, which occurs in several half-periods of the mains voltage, the current decreases to the working one.

It is this moment of start-up that is sometimes destructive for the light bulb. Over time, the spiral of the lamp wears out, becomes thinner, and becomes irregular in its structure. The coil becomes more sensitive to such overloads when turned on, and accordingly, the likelihood of its burnout increases.

It is possible to facilitate the conditions for starting the GLN cold spiral and thereby reduce the likelihood of its burnout. To do this, it is necessary to supply the supply voltage to the lamp not with full, but with a gradually increasing amplitude.

As a result, by the time the full amplitude is applied, the lamp spiral will have time to fully warm up and switch to normal operation.

The microcircuit of the phase regulator K1182PM1R (KR1182PM1) is designed to smoothly turn on / off incandescent lamps or to adjust the brightness of their glow. The maximum operating power is 150 watts. You can significantly increase the power of the connected load by using an external triac. The IC is made in a standard DIP 16 package.

The external view of the device is shown in Fig. 1
IC K1182PM1R (Fig. 5.20, Fig. 5.21) allows, by gradually increasing the phase angle of switching on, to increase the voltage supplied to the lamp. In this case, the spiral has time to warm up to the maximum temperature by the time the full voltage is applied. As a result, the likelihood of the lamp coil breaking down is reduced.
Pins 3 and 6 of IMS DA1 are designed to connect the control circuit (C3 = 100 μF 16 V, R1 = 3.1 kΩ, SW1) with a phase regulator. C1 = C2 = 1 μF 10 V. The time for smooth switching on of the lamp depends on the capacitance of the capacitor C3, and the time for soft switching off depends on the resistance of the resistor R1. The denominations of these elements can be selected independently. With the ratings shown in the diagram, the turn-on and turn-off times are approximately 1 s.
 Most electronic transformers have restrictions not only on the maximum, but also on the minimum total power of the connected lamps. This is due to the peculiarities of the operation of internal converters. The range of permissible power is indicated in the catalog and on the device case, for example, 35-105 W. This limitation, however, does not mean the danger of the transformer breaking down in the absence of a load (for example, when all the lamps burn out). It only follows from it that the normal operation of lamps with a power less than the permissible one is not guaranteed.
For the convenience of connecting lamps, electronic transformers usually have several pairs of output clamps.
Regulation of lamp power, depending on the specific circuit implementation, is carried out in one of two ways:
switching on a transformer with a traditional dimmer;
by applying a special signal to its separate control input (as is the case with adjustable electronic ballasts).

This possibility may not be provided at all. When connecting an electronic transformer to a conventional dimmer design, it is important to ensure that the latter is capable of handling capacitive loads. This information can be found in the documentation for the dimmer.

It should be noted that the secondary voltage on their windings is deliberately slightly reduced in comparison with the nominal, and is usually 11.2-11.6 V. This technique somewhat reduces the luminous flux and light output of the lamps, but prolongs their service life.

Attention! Low voltage halogen lamps (6/12 V) must only be connected to circuits with appropriate transformers. Series connection and other variants are not allowed!

Traditional (electromagnetic) transformers are extremely simple in design and construction. They are no different from their counterparts accepted in radio-electronic practice. Transformers can be both W-shaped and toroidal.

Due to the high operating currents of the lamps, the cross-section of the secondary winding wire reaches 4 mm2. In the case, fuses of various types are usually provided, which the user is informed about by the corresponding marking.In contrast to ballasts, the types of which must strictly correspond to the types of lamps connected, the principle of connecting halogen lamps is much simpler.

The prerequisite is that the total power of all lamps does not exceed the rated power of the transformer. For example, a 60 W transformer can be connected to 12 5 W lamps, 6 10 W lamps, 3 20 W lamps or one 35 or 50 W lamp.

Traditional transformers can be connected to the mains via dimmers for standard incandescent lamps. An exception is the variants of circuits in which the current is rectified, since for them the primary winding of the transformer is actually a short circuit.

Author: Koryakin-Chernyak S.L.

Total comments: 2

  • Дмитрий
    By Dmitry Added on November 13, 2020 at 23:48

    Please tell me how to connect a 12V halogen lamp to a 12V power supply to avoid high inrush current. For example, a 100W 12V DC power supply will not light a 75W 12V halogen lamp, since the starting current will be very large and the protection of the power supply will work.

    To answer
  • Екатерина
    By Ekaterina Added on December 16, 2020 at 13:31

    Install a converter - it will limit the maximum starting current. There are voltage and current adjustments. Example -

    To answer

leave a comment

Your email will not be published.