Morning

Just wanting to know what people run the above lamps on if you don’t have the correct gear for them. Uk based

Thanks

As far as I know, 45W and 60W SO/H and SOI/H low pressure sodium lamps are said to be good for 35W SOX low pressure sodium ballasts. I understand that they both require a 600mA operating current.

Thats only half of the truth. It only applies when leak transformers are used.

Morning

Just wanting to know what people run the above lamps on if you don’t have the correct gear for them. Uk based

Thanks

your best bet is to use a 35/55W SOX choke ballast (35W for the 45W SO/H-SOI/H and 55W for the 60W SO/H-SOI/H) if you have one of those, since a 35W SOX and 55W SOX has very similar running-characteristics to a 45W and 60W SO/H or SOI/H


*but* the 85W SO/H and SOI/H despite being the same physical size as a 55W SOX lamp, must be run on a suitable leak transformer ballast, its arc voltage is too high for 240V Mains choke operation

Quick question then Dez, how come a 90w SOX is safe to run on a 140w SO/H leak transformer, when the 140w lamp is rated at a much higher voltage? Is the leak transformer able to self-regulate for the 90w lamp and it's lower running voltage?

The leak transformer is best simulated as high impedance constant current source. So the the voltage gradient when loaded is very high.

Quick question then Dez, how come a 90w SOX is safe to run on a 140w SO/H leak transformer, when the 140w lamp is rated at a much higher voltage? Is the leak transformer able to self-regulate for the 90w lamp and it's lower running voltage?

As Alex says, a leak transformer ballast is a high OCV, constant current source more or less (assuming a fixed input voltage etc), a prime example of this is how Philips uses this property for example to run all their Spectral Lamps, note how they are all 0.9A rated as they where all designed to run off a 140W SO/H leak transformer ballast (and later a 90W SOX leak transformer ballast) despite the fact some lamps have a voltage drop of just 12V and draw just 12W and others with a voltage drop of 120V drawing 95W

http://www.lamptech.co.uk/Spec%20Sheets/D%20SP%20Philips%20LL%20Xe.htm

http://www.lamptech.co.uk/Spec%20Sheets/D%20SP%20Philips%20LL%20Hg%20HP.htm