Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
  • H05B47/20—Responsive to malfunctions or to light source life; for protection

Definitions

• the invention relates to a method and a device for checking the functionality of an incandescent lamp.
• this arrangement has the disadvantage that a complete monitoring of the functionality, including the detection of possible short-circuits or shunts, is not possible through the exclusive use of the so-called "dark current method". Rather, a first measurement of the so-called cold resistance and a second measurement of the so-called warm resistance must be carried out in order to determine the actual value of the resistance ratio.
• the incandescent lamp is supplied with only low enough energy that it does not light up. In contrast, when determining the warm resistance, the incandescent lamp is supplied with normal energy, so that it lights up completely.
• the known arrangement is also complex because two precise measuring sensors are used to determine the resistance values Detection of the lamp current and the lamp voltage are necessary.
• the arrangement requires a high level of computation, since the resistance values or resistance ratios have to be processed and stored as absolutely correct measured values.
• the energy source for supplying the arrangement must be switchable, since in addition to delivering high energy corresponding to the nominal power for the hot resistance measurement, it must also provide low energy for the cold resistance measurement.
• the known arrangement has the further disadvantage that it must have good current control, since in particular the measurement of the heat resistance when the incandescent lamp is fully lit must always take place at the same operating point. Otherwise, the recorded values would be associated with a large measurement error, in particular for the resistance.
• the measurement in the known arrangement requires a certain amount of time, since both the measurement of the cold resistance and of the warm resistance after switching on the energy source must wait until a steady state occurs at the respective operating point.
• the invention is based on the object
• FIG. 1 shows a block diagram of a lamp circuit according to the invention
• FIG. 2 shows characteristic lamp current curves after connection of an incandescent lamp to a supply voltage for three different functional states of the lamp
• FIG. 3 shows three characteristic current curves after switching on an incandescent lamp with decreasing actual lamp current values at the beginning of the connection
• FIG. 4 shows the three characteristic lamp current curves from FIG. 3, the period of time until the second actual value of the Lamp current are extended with a decrease in the size of the first actual value.
• the energy source 1 is preferably a network connection No more buffer batteries connected via a rectifier.
• the lamp circuit of Figure 4 a measuring device for detecting the actual value of the La -. ⁇ penstromes II and a controllable switching device 5 for attachment or disconnection of the bulb 2 to the supply voltage U Versor ⁇ jj.
• a control device 6 which switches the incandescent lamp 2 to the supply voltage UL for a predeterminable time period T by actuating the switching device 5, and which, according to the invention, has a first actual value ILA and a second actual value ILE of the lamp current is detected by the measuring device 4 at certain times.
• a status signal Z signals the functional status.
• Case A in FIG. 2 first shows the characteristic current profile of an intact incandescent lamp.
• the lamp current II jumps to an initial current value ILAM :
• ILAM initial current value
• a first actual value ILA of the lamp current II is measured at the beginning of the connection and a second actual value ILE is measured at the end of a predetermined period T after the connection.
• the difference ⁇ I ILA ⁇ ILE of the two actual values is determined and a statement about the functionality of the incandescent lamp is derived from this. The existence of proper functionality of the incandescent lamp can be concluded when the difference ⁇ I has exceeded a predetermined lower limit.
• the invention thus has the advantage that it is not necessary to record the actual current values ILA and ILE ⁇ a ⁇ --- ⁇ - n ⁇ r very high absolute accuracy. It is already sufficient to detect the occurrence of a drop ⁇ I in the lamp current after connection to a supply voltage. If namely in accordance with the example shown in Fig. 2 Case B, a filament or line break is present, the first actual value ILA to point the beginning of the connection and the measured upon expiration of the predetermined time interval T second Ist ⁇ ILE worth each 0, and the Difference ⁇ I is also 0. Due to the non-occurring drop in the current drop after connection to the supply voltage, this fault can be reliably detected. In the same way, according to case C in FIG.
• the inventive method is thus characterized beson ⁇ DERS is characterized in that for recording all Lampenfunktions- states the formation of a difference of two Stromistwer ⁇ th is sufficient, the first actual value IA at the beginning of a connection to a supply voltage and the actual value sau ⁇ te ILE na ch expiration of a predetermined time period T thereafter be picked.
• the duration of the time period T is predetermined as a function of the current size of the first actual value at the beginning of an activation, such that when a decrease in the first actual value occurs, especially in comparison to the expected size of its nominal value, the duration of the period until the measurement of the second actual value is extended. This is further explained with the aid of the courses shown in FIGS. 3.4.
• FIG. 3 shows three characteristic current profiles I, II, III which occur after the incandescent lamp has been connected to a supply voltage.
• the courses differ in the size of the first actual value of the lamp current that occurs at the start of the connection.
• the first profile I thus has a large first actual value ILIA, which preferably corresponds to the normal current value to be expected at this moment.
• the first actual value IL2A is noticeably smaller in case II and has further decreased to size IL3A in case III.
• the differences ⁇ ILI ⁇ IL2» - I L3 take from the measured values Istwer ⁇ th from increasing.
• the reason for a decrease in the respective first actual values of the lamp current and consequently the decreasing values of the differences ⁇ IL2 ′ ⁇ IL3 due to the increasing flattening of the respective drop in the lamp current can be seen in a temporary decrease in the supply voltage UL or in different values of the line resistance 2 in the lamp circuit due to location-dependent different line lengths.
• the duration of the period T, Tl, T2 or T3 is specified according to the invention depending on the current size of the first actual value ILIA » I L2A, L I L3A at the beginning of a connection in such a way that when a decrease in the first occurs Actual value according to the cases I, II, III shown in Fig. 3.4, the duration of the period Tl, T2, T3 is extended until the measurement of the second actual value I L1E ' I L2E' I L3E.
• a first actual value ILIA is measured in the first course I at the beginning of the connection and the second actual value LIE is measured after the time period T1. From this, a difference ⁇ ILI can be derived, the value of which is sufficiently large to detect the correct functional state of the incandescent lamp.
• a first actual value IL2A of the lamp current occurs at the beginning of the connection, which has a reduced value.
• the duration of the period T2 is extended and the second actual value IL2E is only determined when it expires.
• At least one further, third actual value is measured inside the period T or Tl, T2, T3, which is temporally between the first and second actual values.
• the method according to the invention can be further refined by adding such further measuring points. Is z. If, for example, a short or shunt is shown in FIG. 2, case C occurs and a voltage drop occurs during the period C, in this rare exceptional case the second actual value ILE at the end of T is less than ILA »although both values should be approximately the same. There is now a noticeable difference between the two actual values, so that an error-free lamp circuit would be incorrectly reported.
• the first actual value IL2A is smaller than the comparison value I IA of case I, such a reduced current with a correspondingly less pronounced decay behavior can flow through the incandescent lamp 2 for a longer period T2 without a Illumination of the same is to be feared. Due to the lower lamp current between the values IL2A and IL2E, the filament heats up correspondingly more slowly, so that no illumination has yet occurred at the end of an extended period T2 or T3. After tapping the second actual value of the lamp current at the end of the period T1, T2, T3, the lamp can thus be disconnected from the supply voltage again without affecting the functionality of the checking method according to the invention or the checking device.
• the current duration of the period T or Tl, T2, T3 can preferably be based on the relationship
• K represents a constant depending on the type of lamp
• the lamp current also continues to flow beyond the end of the respective time period and the incandescent lamp is completely illuminated. Accordingly, in FIGS. 2, 3, 4 the falling course of II in each case A or I is also beyond the end of the period T or Tl extended in the form of a dashed line.
• the device according to the invention according to FIG. 1 is finally also suitable for the control device 6, after the incandescent lamp 2 to be completely switched on, to switch the lamp current II to a predetermined pulse-pause ratio by pulsing the switching device 5 regulates the specified value.
• the components lamp current measuring device 4, switching device 5 and control unit 6 according to FIG. 1 can thus be used advantageously both for carrying out the method according to the invention and for regulating the lamp current when the incandescent lamp is switched on completely.

Landscapes

• Circuit Arrangement For Electric Light Sources In General (AREA)
• Photometry And Measurement Of Optical Pulse Characteristics (AREA)
• Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8210058

Family Applications (1)

Country Status (9)

Cited By (2)

Citations (2)

• 1993
  • 1993-09-10 EP EP93920701A patent/EP0662276B1/de not_active Expired - Lifetime
  • 1993-09-10 DE DE59302071T patent/DE59302071D1/de not_active Expired - Fee Related
  • 1993-09-10 WO PCT/EP1993/002454 patent/WO1994008438A1/de active IP Right Grant
  • 1993-09-10 CZ CZ95585A patent/CZ283430B6/cs unknown
  • 1993-09-10 AT AT93920701T patent/ATE136189T1/de not_active IP Right Cessation
  • 1993-09-10 SK SK378-95A patent/SK37895A3/sk unknown
  • 1993-09-10 ES ES93920701T patent/ES2085171T3/es not_active Expired - Lifetime
  • 1993-09-10 DK DK93920701.5T patent/DK0662276T3/da active
• 1995
  • 1995-03-23 FI FI951382A patent/FI951382A0/fi unknown

Patent Citations (2)

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