I've just acquired a 6.6A series incandescent lamp made by Osram, and I'm wondering the best way to go about lighting it. I know relatively little about incandescent series street lighting, as I'm not aware of it ever being used in any areas of the UK that I am familiar with, but I know it was popular in the US.

Is there a safe voltage I could use on the Variac or would I need some form of current limiting device..?

Thanks in advance,

Ria 

If you have a multimeter you can measure the resistance and use the ohms law formula: V=I*R.

If you have a multimeter you can measure the resistance and use the ohms law formula: V=I*R.

NO

Coil resistance changes DRAMATICALLY with its temperature. If you don't know the nominal voltage, Use a variable autotransformer and increase the voltage until the current reads 6.6A.

Thanks, that was good advice. I ran it on the Variac with the multimeter as an ammeter and it got up to 7V, probably around 6.6V..! Doesn't seem like a lot, but then I suppose with lots of lamps all in series it adds up.

Very interesting, I have learnt something today 

It was wonderful to see it lit 

It was wonderful to see it lit 

Do you have a picture of it?

Do you have a picture of it?

We do, see here:  unlit and lit 

I've lit series lamps on a car battery charger w both 6 and 12 volts. Also added a 12 volt battery in series for 18 or 24 volts.

Yeah, I've got two or three of them in series on the Variac now. It's an interesting concept, we never had it here.