Why does the lamp have a coil?

[DIYspanner]

I've dismantled it to check for bad connections - not working!

It appears to have a large coil (it uses a G4/G9 220V Halogen bulb)

The only voltage is the mains from the incoming cable. No voltage on the other side of the coil.

Why does the lamp have a coil?

Do I presume from tests that the coil has an open circuit fault?

Here's the photos -

 

[Echo the husky]

The 'coil' is a transformer. The lamp will almost certainly be a 12 Volt reflector type. Such as:

You will need to check the rating plate to see what the maximum wattage permitted is, it should also state the lamp voltage.

 

[bernardgreen]

The coil appears to be a toroidal transformer which suggests the lamp uses a bulb that is not 230 volt.

If there is 230 v AC between the Red and Blue and no voltage between the two Black then that would suggect the trnasformer has failed.

Edit Too slow

 

[JohnW2]

I've dismantled it to check for bad connections - not working! It appears to have a large coil (it uses a G4/G9 220V Halogen bulb) The only voltage is the mains from the incoming cable. No voltage on the other side of the coil. Why does the lamp have a coil?

Are you absolutely certain that it uses 220V (or 230/240V/whatever)?

That 'coil' looks like a toroidal transformed, designed to reduce the mains voltage (quite probably to about 12V) for the bulb. Have you tried measuring voltage on the 'other side' of the coil (i.e. between the two blacks) with a meter on a lower violtage range (e.g. 20V)?

Kind Regards, John

 

[333rocky333]

we use them all the time, its a 50va transformer they take up to 50 watt G5.3 dichroic lamp, when they fail we use a replacement from Rs components, sometimes its a faulty lampholder so put a good lamp direct on the transformer output wires to test, do not use a G9 lamp as there 240 volt or a G4 as the pins may be too loose, sometimes the lampholders screw on to the pins.

People in the past have mentioned the Rs ones should not be used as they will get shorted turns being in the metal casing, but with the supplied neoprene gaskets i am not sure it is a problem and they have seemed ok, if you have a void behind the light you can use any electronic transformer

https://uk.rs-online.com/web/p/prod...VrrvtCh0EcQmPEAYYAyABEgJm-vD_BwE&gclsrc=aw.ds

 

[JohnW2]

we use them all the time, its a 50va transformer they take up to 50 watt G5.3 dichroic lamp ...

What voltage - 12V?

Kind Regards, John

 

[bernardgreen]

People in the past have mentioned the Rs ones should not be used as they will get shorted turns being in the metal casing, but with the supplied neoprene gaskets i am not sure it is a problem

The problem is when a single turn is created when the ends of the fixing stud are both in contact with metal.

 

[DIYspanner]

Thanks All for posting!

Indeed its a transformer!

I tested between the output wires and the meter confirmed 11V ac. I'd been testing to mains earth!

One other concern is the lip and groove joint of the metal body halves. There's no rubber seal and being for outdoor use, is that safe?

Noted on the type lamp to use by the way!

 

[333rocky333]

The older ones had a rubber pushed into the groove i think, i dont recall seing them on the newer ones, sometimes the fittings shape is designed that the water just runs round and away.
The wire into the screw on lampholders usually perishes and corrodes causing failure, if you have 11 volt then i would suspect that holder, test the voltage there.

 

[333rocky333]

What voltage - 12V?

Kind Regards, John

They state use a 12 volt lamp but i dont think theres markings on the transformer, the RS ones are 11.something volts, they work ok with dichroics, but Led i would be doubtfull.
not just of the voltage but the heat in the lamp housing

 

[333rocky333]

The problem is when a single turn is created when the ends of the fixing stud are both in contact with metal.

View attachment 147179

Ok thanks, in that fitting, to hold it in, theres just a big washer and a bolt that screws into the back plate, so i reuse that, it does not touch the front plate, also there made of that sort of cast alley metal, that, corrodes and goes grey and the paint flakes off, if that makes a difference.

 

[ban-all-sheds]

Here's the photos -

No.

This is how your post looks:

 

[333rocky333]

i can see them ok

 

[phatboy]

No.

This is how your post looks:

View attachment 147190

Looks fine to me. Maybe you are blocking https://images.weserv.nl where the OP has hosted his photos?

 

[JohnW2]

The original looked fine to me (photos and all), too. As you say, I think it's another case of BAS depriving himself of images.

Kind Regards, John