SO/H and SOI/H low pressure sodium lamps on ignitor chokes? « on: November 12, 2021, 05:25:49 PM » Author: WorldwideHIDCollectorUSA
Since SO/H and SOI/H low pressure sodium lamps are often the predecessors of modern SOX low pressure sodium lamps, I often see people saying that SOI/H and SO/H low pressure sodium lamps are often interchangeable with SOX low pressure sodium lamps on the same ballasts. When I looked at the 85w and 140w SO/H and SOI/H low pressure sodium lamps, they have an arc voltage somewhere between 140v and 160v, which seems pretty high for operation on 220-240v ignitor choke ballasts. I would like to know if 85w and 140w SO/H and SOI/H low pressure sodium lamps are able to satisfactorily operate on the 220-240v ignitor choke ballasts that are intended for 55w and 90w SOX low pressure sodium lamps respectively or whether they really need high OCV HX autotransformer ballasts.
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Desire to collect various light bulbs (especially HID), control gear, and fixtures from around the world.

DISCLAIMER: THE EXPERIMENTS THAT I CONDUCT INVOLVING UNUSUAL LAMP/BALLAST COMBINATIONS SHOULD NOT BE ATTEMPTED UNLESS YOU HAVE THE PROPER KNOWLEDGE. I AM NOT RESPONSIBLE FOR ANY INJURIES.

	Re: SO/H and SOI/H low pressure sodium lamps on ignitor chokes? « Reply #1 on: November 12, 2021, 05:48:54 PM » Author: Rommie
The answer is yes and no. The 85W SO/H and SOI/H lamps both operate at 0.6A, whereas the 90W SOX runs at 0.9A. so they are not interchangeable. The 140W SO/H & SOI/H lamps are also 0.9A so could probably run on a 135W ballast, but these lamps were designed for leak transformers. Choke/ignitor circuits did not come in until SOX was well established. The highest wattage lamp of this type I have is an 85W SOI/H, which runs fine on the Philips L4045 ballast, as do the 45W and 60W versions. 35W and 55W SOX lamps also run fine on this ballast, but a 90W SOX lamp would not.
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Ria (aka Rommie) in Aberdeen
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	Re: SO/H and SOI/H low pressure sodium lamps on ignitor chokes? « Reply #2 on: November 12, 2021, 05:51:06 PM » Author: WorldwideHIDCollectorUSA
Would the 85w and 140w SO/H and SOI/H lamps have a hard time maintaining an arc on ignitor choke ballasts? For example, would a 85w SO/H or SOI/H lamp have a hard time maintaining an arc on a 55w SOX ignitor choke? In addition, would a 140w SO/H or SOI/H lamp have a hard time maintaining an arc on a 90w SOX ignitor choke?
« Last Edit: November 12, 2021, 05:58:42 PM by WorldwideHIDCollectorUSA »		Logged

Desire to collect various light bulbs (especially HID), control gear, and fixtures from around the world.

DISCLAIMER: THE EXPERIMENTS THAT I CONDUCT INVOLVING UNUSUAL LAMP/BALLAST COMBINATIONS SHOULD NOT BE ATTEMPTED UNLESS YOU HAVE THE PROPER KNOWLEDGE. I AM NOT RESPONSIBLE FOR ANY INJURIES.

	Re: SO/H and SOI/H low pressure sodium lamps on ignitor chokes? « Reply #3 on: November 12, 2021, 05:57:30 PM » Author: Rommie
Not sure to be honest, I've never tried. I don't have a 140W lamp as yet and I'm not about to risk the rare 85W ones when I have the correct ballast for them.
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Ria (aka Rommie) in Aberdeen
Administrator, UK & European time zones. Any questions or problems, please feel free to get in touch

"What greater gift than the love of a cat..?" - Charles Dickens
*** No smiley-only replies, please ***

	Re: SO/H and SOI/H low pressure sodium lamps on ignitor chokes? « Reply #4 on: November 12, 2021, 06:00:43 PM » Author: WorldwideHIDCollectorUSA
Maybe James can chime in on this subject.
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Desire to collect various light bulbs (especially HID), control gear, and fixtures from around the world.

DISCLAIMER: THE EXPERIMENTS THAT I CONDUCT INVOLVING UNUSUAL LAMP/BALLAST COMBINATIONS SHOULD NOT BE ATTEMPTED UNLESS YOU HAVE THE PROPER KNOWLEDGE. I AM NOT RESPONSIBLE FOR ANY INJURIES.