Flickering of HID lamps of low frequency square wave electronic ballast « on: December 01, 2010, 03:22:23 AM » Author: dor123
Most HID electronic ballasts operates the lamps at low frequency square wave (83hz in the case of the EHID ballasts of Eltam Ein-Hashofet), to prevent resonance in the arctube. However, these frequencies are barely higher then the mains frequency (50hz in Europe and Israel, 60hz in North American). are HID lamps flickers at this type of electronic ballasts?
		Logged

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Flickering of HID lamps of low frequency square wave electronic ballast « Reply #1 on: December 01, 2010, 11:12:47 AM » Author: Medved
No, because these electronic ballasts operate with square-wave current, so the power delivered to the lamp is constant over the whole period, it has less then few 10's of us (depend on exact ballast concept, some have only about a us) cuts, what are not visible. Standard magnetic ballast operate the lamp with the sinewave (series inductor, HX auto transformer), so the power fluctuate in the shape of the "rectified sinewave" (so about a  millisecond is below 50% level). CWA ballasts are even worse, they supply the lamp with quite short peaks, so the lamp effectively lights only for about 1..2ms from the 4.3ms long halfwave.
		Logged

No more selfballasted c***

	Re: Flickering of HID lamps of low frequency square wave electronic ballast « Reply #2 on: December 01, 2010, 11:23:11 AM » Author: dor123
Thanks. So the lamp actually delivers constant light like lamps that operated from batteries and recives DC, and don't flashing 166hz or 166 flashes/secs or double the ballast frequency.
		Logged

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Flickering of HID lamps of low frequency square wave electronic ballast « Reply #3 on: December 03, 2010, 03:35:28 AM » Author: Lampwizard
No, the lamp still does flicker at each lamp current commutation but the commuation frequency as well as the "dead time" (i.e. time with reduced/no light output) is so short that the eye/brain cannot register. So it is perceived as flicker-free.
		Logged

Philips colour 27: best fluorescent tube colour.

	Re: Flickering of HID lamps of low frequency square wave electronic ballast « Reply #4 on: December 03, 2010, 06:36:35 AM » Author: dor123
Are digital cameras can detect flickering from HID lamps that operates at low frequency, square wave current?
		Logged

I"m don't speak English well, and rely on online translating to write in this site.
Please forgive me if my choice of my words looks like offensive, while that isn't my intention.

I only working with the international date format (dd.mm.yyyy).

I lives in Israel, which is a 220-240V, 50hz country.

	Re: Flickering of HID lamps of low frequency square wave electronic ballast « Reply #5 on: December 03, 2010, 03:04:38 PM » Author: Medved
I think thez would not register it, as the "dead time" is way shorter then the shutter. Moreover the discharge has some inertia (few to 10's of us) in generating light, what will on many systems cover the dead-time. But this depend on how long is the dead-time with particular ballast and how long is the lamp's inertia...
		Logged

No more selfballasted c***