It is the smallest lamp in the series of DRL lamps without ignition electrodes. Congratulations. I always find the history of these lamps interesting.

The comparison between the four lamp types (250W, 500W, 750W, 1000W) from the series without ignition electrodes and the six lamps from the series with ignition electrodes is shown again here in two different tables:














I personally note that the MELZ data sheet specifies a running voltage of 120 V to 150 V, while a pocket book specifies 140 V for all 4 lamps without ignition electrodes. That is a significant difference.

Is this actually the case? The distances between the electrodes are all different for the four different lamps. Do you have a way of re-measuring these values yourself on the lamps?

Thank You, Olav! I will try to measure voltage drop on arc tubes at least with two lamps. In future I can try to measure on all lamps.

I have two questions regarding these lamps: What ballast do these run one? The thematic only shows an interfering filter and a box with 4 connections. The fact it shows the inference filter makes me believe these use a choke+starter switch. However it also could be an autotransformer. 2) How dose the phosphor looks like? I have a 500W lamp, and the fluorescent coating has a hint of yellow in the coating.

For this series was used special typeof magnetic ballast with integrated ignition circuit -- with capacitor, sparkgap and low turns transformer in series with main choke. Phosphore of these lamps have green line, so the light was slightly unusual.