DE2817175A1 - Starting circuit for fluorescent lamp - has mains transformer switched at output to resistive or capacitive voltage divider which briefly raises potential - Google Patents

Abstract

The starting circuit has a transformer (8) to generate an increased voltage and connected at its output to a resistive voltage divider (9, 10) whose tapping acts as a capacitive aid to starting. After roughly one second has elapsed this starting potential increases considerably. The voltage divider may contain capacitors instead of resistors. The voltage divider tapping may be earthed or connected to ground at the lamp. A relay switches the divider across the transformer output and is controlled by a timing circuit (12). The transformer input side is connected to the 220V ac mains. A diode bridge may be connected in place of the relay.

Description

D e s c h r e i b u n g Switching arrangement of a capacitive ignition device for fluorescent lamps The invention relates to a switching arrangement for starting BEZW. Ignition of fluorescent lamps, with a choke in connection with a heating transformer serves as a ballast. In order to ensure reliable ignition with such a switch arrangement In general, an additional capacitive ignition potential is to be achieved created with the help of an ignition transformer.

This known device has the major disadvantage that the Fluorescent lamp ignites immediately after switching on because the capacitive ignition aid takes effect immediately. The immediate ignition of the fluorescent lamp makes the necessary Preheating of the heating coil has not been waited for, which has a damaging effect on Relation to the lamp life. Dei inherits from such a mode of operation lamp consumption per switching of around 0.5 to 1 hour. Will this circuit Switched several times a day, as is the case, for example, in U- and S-Bahn trains, see above The life of fluorescent lamps can hardly be half that of normal gear reach.

The solution according to the invention to this problem in a pre-switching device of the type mentioned at the beginning is characterized in that this auxiliary ignition transformer is loaded by a voltage divider and the connection point of these voltage divider resistors respectively the voltage booster capacitors serve as a capacitive starting aid, whereby after After about one second, this ignition potential increases significantly.

Using the '-b. Ag is supposed to follow the practice of the well-known Scha1twcee be explained.

The alternating voltage (1) is e.g. 220 V with a frequency of 50 Hz or can be arbitrarily higher, the capacitor (2) as a Kcmpensationskondensator serves. The choke (5) has the task of limiting the current for the lamp (4) while the heating transformer (5) preheats the lamp electrodes. Of the The auxiliary ignition transformer (6) with the protective resistor (7) is used with its increased Voltage potential as a capacitive starting aid, so that the lamp can also operate at low Room temperature shows a willingness to work.

Fig. B) shows a circuit diagram in which the principle of the invention is shown is. The auxiliary ignition transformer (8) is connected to the voltage divider resistors (9) and ('°? when the switch (11) is closed). The connection point (13) is connected to the ground or to the lighting fixture ground. If you choose that now Resistance ratio of (9) and (io) so that point (13) is about halfway through If the supply voltage is present, the lamp shows an unwillingness to ignite, even when it is relatively high line voltage. After about a second, the relay interrupts this circuit, so that the ignition potential (ins) practically jumps to the upper end of the ignition transformer, whereby the lamp ignites safely. During this first second took place unhindered the preheating of the lamp, whereby a gentle 3etr- »b is ensured.

The solialt delay is achieved with the aid of the timer (12).

Instead of the mechanical relay, an electronic switch, z.9. a triac, kick.

Fig. C) shows a further embodiment of the invention.

The auxiliary ignition transformer works with a resistor, which has a bridge rectifier in series, and a further supplementary resistor. A suitably sized capacitor is connected to the DC terminals of the bridge rectifier, which is charged quickly when it is started up, thereby increasing the ignition potential is moved up. A correspondingly high-resistance discharge resistor lies parallel to the capacitor, so that nothing stands in the way of re-ignition.

Fig. D) shows an embodiment where instead of the capacitor a PTC thermistor is used.

For a lighting system in which only one lamp is operated can be used in place of chokes, heating transformers and auxiliary ignition transformers a stray field transformer step.

Claims (1)

Claim Switching arrangement of a capacitive auxiliary ignition device for fluorescent lamps, with the help of a transformer an increased voltage potential is generated, according to claim 1, characterized in that this ignition auxiliary transformer is loaded by a voltage divider, and the connection point of this voltage divider serves as a capacitive ignition aid, and that after about one second has elapsed Ignition potential increases significantly. Claim 2: Switching arrangement according to Claim 1, characterized in that that instead of the voltage divider resistors, capacitors are used,