DE1224406B - Device for operating fluorescent lamps, fed from an alternating current network with 16 2/3 Hz - Google Patents

Description

Device for operating fluorescent lamps, fed from one AC mains with 162/3 Hz The operation of fluorescent lamps with low frequency Up to now, a current of 16F / 3 Hz was practically non-existent due to strong flickering feasible. Attempts have already been made by rectifying and smoothing this current to reduce the flickering so much that only a slight disturbance can be seen in the light was: The smoothing terms necessary for this, however, assume such larger ones: that this approach was not considered in practice. While incandescent lamps result their inertia are easier to get flicker-free, the smoothing effort becomes for operating fluorescent lamps many times larger.

Even with the greatest effort on smoothing elements, there is a flicker effect on fluorescent lamps should not be lowered so far that a sensitive eye is not disturbed feels.

In order to be used in railway operations, e.g. B. for equal systems or level crossings Until now, 50 Hz networks - external power supply - were used to get perfect light - claimed.

The great expense of lines and expensive external power had to be hitherto be accepted.

The electrical energy for the lighting in passenger coaches was previously fed to the battery via the axle generator.

Using a rotating converter and transformer was a frequency of about 100 Hz at 220 volts. Every fluorescent lamp is a ballast assigned, which determines the lamp current. A special control device ensures for the control of the generator and the correct characteristics for the charge the battery.

This large chain of very expensive facilities requires that one Such a system becomes unprofitable, has a poor degree of efficiency and needs to be expected is.

A device for operating fluorescent lamps has now been fed found from an alternating current network of 16 2/3 Hz, which is characterized is that according to the invention the alternating current after its rectification only in one is smoothed to a small extent and with the undulating direct current a transistor inverter is fed by a stray field transformer, which works at a high frequency and delivers almost a stabilized lamp current.

The mode of operation should be explained using the illustration. The supply voltage 1, which has a low frequency, is optionally via a transformer the rectifier 2 and the smoothing element 3 are supplied.

The transistor ballast 4, which in a known circuit and Sizing works at a high frequency, the fluorescent lamp feeds 5.

The transistor ballast, consisting of two push-pull switches Transistors and a stray field transformer, has the property that the lamp current changes very little with fluctuations in the input voltage.

This current-stabilizing behavior of the transistor inverter or ballast for the fluorescent lamp results because the inverter frequency practically proportional.

As a result of the constant stray field effect, there is a constant one Lamp current. This lamp current stabilization effect can be achieved by suitable dimensioning of the switching elements can be made particularly effective.

By applying additional stabilization measures, e.g. B. vice versa proportional to the input voltage dependent modulation of the transistors, can practically 100% stabilization of the lamp current can be achieved. The necessary The smoothing element can be made particularly small.

The invention consists essentially in the fact that the coarse reduction of waviness the supply current for the ballast through a relatively small smoothing element is achieved, while the necessary fine compensation of the lamp current by suitable Dimensioning of the ballast is achieved almost free of charge. Occurring fluctuations of the supply voltage are simultaneously determined by the characteristics of the ballast balanced. The particular advantages of the facility found consist in the fact that 1. an absolutely flicker-free light with fluorescent lamps 2. the setup is very easy and cheap, 3. the setup No maintenance required, 4. The input voltage fluctuations are automatically regulated 5. a high electrical efficiency occurs, 6. the facility very is small and light, 7. no flicker occurs due to the high operating frequency.

The found facility has one for the electric train lighting of particular importance because a number of very expensive units are completely in Get lost. Absolutely maintenance-free is guaranteed. By The stabilized lamp current will also maximize the life of the fluorescent lamps achieved.

Claims (3)

Claims: 1. Device for operating fluorescent lamps, fed from an alternating current network with 162/3 Hz, characterized in that the Alternating current is smoothed only to a small extent after its rectification and with the still slightly wavy direct current, a transistor inverter with a stray field transformer is fed, which works with a vain high operating frequency and almost a stabilized lamp current supplies. 2. Device for operating fluorescent lamps according to claim 1, characterized in that the lamp current stabilizing Behavior of transistor ballasts due to an inversely proportional to the input voltage dependent modulation of the transistors is improved. 3. Device for operating fluorescent lamps according to claim 1 and 2, characterized in that a central input transformer with a rectifier and smoothing element is arranged for the operation of several fluorescent lamps. Considered publications: German Auslegeschriften No. 1077 328, 1d'49 976, 1131803, 1081143; German utility model No. 1846 695: