Old Thorn fluorescent starter

[Maxiii]

Does anyone know an outlet for old thorn starters, mine are two inch long in metal sleeve marked AM? 32001 , photos attached.

 

[Harry Bloomfield]

It's a perfectly standard, two pin starter, easily available from many outlets. You don't need to buy a Thorn item, just one which is suitable, for the tube wattage.

 

[Maxiii]

Hi Thank you, There are four pins on it , two larger ones and two small. And the length and circumference of it are larger than modern ones though, or are there similar sized ones as dimensions are not specified in online outlets

 

[Harry Bloomfield]

Hi Thank you, There are four pins on it , two larger ones and two small. And the length and circumference of it are larger than modern ones though, or are there similar sized ones as dimensions are not specified in online outlets

Oh, OK, I missed that - in which case, it makes that entire fitting scrap. Just replace it with a modern LED version.

Four pin starters, went out, in the 1950's, which means the fitting much be at least 75 years old.

 

[Maxiii]

It's a perfectly standard, two pin starter, easily available from many outlets. You don't need to buy a Thorn item, just one which is suitable, for the tube wattage.

Hi Thank you, There are four pins on it , two larger ones and two small. And the length and circumference of it are larger than modern ones though, or are there similar sized ones as dimensions are not specified in online outlets

 

[Maxiii]

Oh, OK, I missed that - in which case, it makes that entire fitting scrap. Just replace it with a modern LED version.

Four pin starters, went out, in the 1950's, which means the fitting much be at least 75 years old.

You are not wrong they are that old , it’s just that everything else is in very good condition the previous owner was an electrician and carpenter , there are millions of old new still boxed components in the work shed which could rebuild so many electrical things like this starter I imagine but I wouldn’t recognise any of them , plus complex looking testers combining gases and whatnot , but alas no one who can use them , I have been reluctant to throw them away. I shall have to replace the fittings as you say. Thanks Harry.

 

[ericmark]

From memory, the pins on all the fluorescent tubes were the same, I know the 65 watt fitting would take a 58 watt tube, but the problem is the voltage has changed, and fluorescent lights are very dependent on voltage.

But a LED tube will fit, the problem is the starter.
The starter is replaced with a fuse, but not really required,

the diagram is shown here, the new fluorescent tube is only supplied one end, the other end is a short circuit, so with the method shown it does not matter which way around the tube goes.

 

[ericmark]

Out of interest, this is how the old fluorescent was wired.

 

[accelerator]

It's probably worth replacing with an LED light because you will save money on the electricity long term.

 

[Harry Bloomfield]

From memory, the pins on all the fluorescent tubes were the same, I know the 65 watt fitting would take a 58 watt tube, but the problem is the voltage has changed, and fluorescent lights are very dependent on voltage.

Many of those old fittings, which used 4-pin starters, came with BC lamp holders at the tube ends. Really not worth the messing to convert, when a complete LED fitting can be had.

 

[Harry Bloomfield]

View attachment 392550Out of interest, this is how the old fluorescent was wired.

Actually, no this one is a 4-pin starter.

 

[Maxiii]

View attachment 392550Out of interest, this is how the old fluorescent was wired.

I will take the covers off and provide photos of the wiring tomorrow so I can ask if I can just replace the light with LED light and no starter at all. The ends of the existing flu tube is two prongs.

 

[Maxiii]

Actually, no this one is a 4-pin starter.

I will take the covers off and provide photos of the wiring tomorrow so I can ask if I can just replace the light with LED light and no starter at all. The ends of the existing flu tube is two prongs.

 

[ericmark]

It's probably worth replacing with an LED light because you will save money on the electricity long term.

Not quite as easy as that, since the standard swap leaves the ballast in place, there is a volt drop across the ballast which the LED tube manufacturers ignore, so a 22 watt LED tube in a 5-foot fitting is not really 22 watt unless the ballast is removed, it is more like 26 watt.

Also, only 22 watt rather than 58 watt, so light output when one looks at lumens is 2200 lumens against around 5000 lumens, I say about, as the electronic ballast gives a higher output from the same tube and uses less power. So electronic around 5400 lumens and 54 watt, but wire wound 5000 at 58 watt but the latter also dependent on voltage, so I did experiments with 127 and 110 volts and there was a huge difference, 0.6 amp to 1 amp.

But if 2200 lumens are enough, then why fit a tube with an output of 5000 lumens? And due to the spread on a tube, the LED tube shines near nothing towards the fitting, we also have a gain. In my kitchen, the 65 watt was changed to 58 watt then 22 watt, then sold house and down lighters fitted, looks more modern but back to 60 watt, and never noticed the changing light levels.

But basic fact there is very little gain fluorescent to LED, all it means is swapping mercury for arsenic, as to which is the most dangerous I don't know.

 

[Harry Bloomfield]

I will take the covers off and provide photos of the wiring tomorrow so I can ask if I can just replace the light with LED light and no starter at all. The ends of the existing flu tube is two prongs.

Don't mess about converting, just buy a complete LED fitting. The outcome will be much neater, and more satisfactory all round.