PDSH 995 Voltage across lamp during pre-heating time
http://decisions.iecee.org/icons/ecblank.gif PDSH 995
Voltage across lamp during pre-heating time
7
60929(ed.2) & 60929(ed.3) & 60929(ed.4)
Standard(s):
IEC 60929 All editions
Subclause(s): 7
No. Year PDSH 0995 2010
Category: LITE Developed by: ETF5 OSM/LUM
Subject:
Voltage across lamp during pre-heating time
Key words:
- Residual d.c. voltage
- Measurement
- Pre-heating time
To be approved at the 49th CTL Plenary Meeting, in 2012
Question:
The standard requires that during the pre-heating time, the open circuit voltage across the lamp
substitution resistor, shall not exceed the maximum values specified on the lamp data sheets. On the
ballast in question we found during the pre-heating time an open circuit voltage waveform which is the
sum of a d.c. voltage and the high frequency voltage created by the oscillating circuit. If we measure the
voltage in this condition, we find a value which is higher than the limit. The d.c. voltage is a residual
voltage stored in a little capacitor of about 5-10 nF and has no enough energy to start or to damage the
lamp. If we repeat the measurement with an high resistance (10 K) between the two cathodes, we find
the indicated voltage waveform. In this condition the test is OK.
Decision:
Do not take into consideration the residual d.c. voltage when making the measurement.
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