Old school Bay lights.

[p0689109]

I have just obtained a couple of these type of units and they both have a 400w light in them on a E40 holder. Screw thread type fitment. Why do these bulbs need to use a transformer. The one that had any info on had input 240v 50Hz output 120v 75hz. Now I am not too sure if these bulbs were for the original fitment as the wiring is not too good. In fact one of the units had had a bit of a wire overheating problem. The bulbs just had the two wires to the holder but again I don't know. I have got some Thorn 300w bulbs which are normal bulbs( as opposed to helium or the like) but bigger. Can these just be used like a normal say 100w bulb?
As you can tell I am not too au fait with the witchcraft side of things. I have just googled high bay and they mention Metal Halide lights so is that what the transformers are for?

 

[dannyp]

i think the transormer is there to controll the power the buld trys to take. i belive it may be a constant current source as when the lamp is cold it has a relativly high resistance but once its up to temp the resitance is very low

 

[p0689109]

OK thanks for that dannyp.
As luck has it I won half a dozen Thorn 240v 300w bulbs with standard(household size) ES ends so I will just put them in the fittings. But it is nice to find out how things you do not know a lot about works.

 

[p0689109]

The bulbs are just standard bulbs but 300W. I have already fitted one to my garage bench light and they work so I will be fitting them. I got them from my local weekly auction at one of the Estate agents in Congleton.