Philips HPI-T Plus 400w/645 starting and running without ignitor

Who says that you always need an ignitor for starting and operating Philips HPI-T Plus 400w/645 metal halide lamps? In this video, you can see that my Philips HPI-T Plus 400w/645 metal halide lamp is able to start and operate directly off a North American 400w M59 probe start metal halide ballast without using an external ignitor despite the lamp not having a starting electrode in the arc tube. How is this possible? Let’s put it this way, In Europe and most of the world outside North America, most metal halide lamps needed a high voltage ignitor for reliable ignition. However, In North America and parts of Asia, there were some metal halide lamps that can start without an ignitor. These lamps are known as probe start metal halide lamps. They consisted of a starting electrode to allow for lower ignition voltages compared to pulse start metal halide lamps. However, in order to ignite them, they would require a significantly higher OCV compared to mercury vapor lamps. In most countries in the world outside North America, there was a need to reliably ignite them directly off a reactor/choke ballast off a 220-240v mains supply. Those countries have been able to achieve this by designing low voltage ignitors to allow the lamps to ignite reliably on 220-240v mains using reactor/choke ballasts while preventing damage to the starting probes and starting electrodes of probe start metal halide lamps. Interestingly, Philips of Holland was able to design a metal halide lamp that was able to ignite with a lower starting voltage than pulse start metal halide lamps despite not having a starting probe and electrode. The design that they came up with is known as the Philips HPI lamps. These lamps were able to ignite on low voltage ignitors despite not having starting probes and electrodes due to the fact that their arc tubes contained neon argon penning mixtures. Because of the fact that Philips HPI lamps and probe start metal halide lamps have similar ignition voltage requirements, I was able to get my Philips HPI-T Plus 400w/645 lamp to ignite directly off a North American 400w M59 probe start metal halide ballast using no ignitor at all. However, in order to ignite them off 220-240v mains using a reactor/choke ballast, you would still need an ignitor for reliable starting and ignition.