Hey guys, found your educational forum while researching for info on some 'toroidal transformers' I picked up on eBay to use in a 'home electrical testing safety project', and am hoping someone here has some insight to my quest...
Basically, I've built myself a 'Dim Lamp Isolating box' for testing vintage devices and other power supplies (without blowing them up , or myself) and I need a 240v in , 240v out toroidal (isolation) transformer to drop into the middle of it (see image of my freshly made scary looking death box below).
Problem is, none of the transformers came with wiring diagrams and there are LOTS of pretty coloured wires sticking out, and I have no clue what they all do, as I have never even seen one before now. But, I'm hoping someone here does....
Dim Lamp Isolator (aka, The Box of Death)
(has 4 switchable test lamps, LED display, fuse, added trip switch, socket, and TEST/LIVE 'bypass' switch)
The last piece of the build-puzzle is the 'Isolation transformer', so I bought 3 x different cheap eBay toroidal transformers in the hope that at least one has the requirements for what I need. (i.e. basically only need, 240v AC in and 240V AC out). But the problem is, I think these transformers are so old there are no schematics in Google to be found.
These are the toroidal transformers in question:
1. AMETHYST DESIGNS LIMITED - AD3285T TT3001 0107 (info from seller was; "300va transformer 3.5kgs and 120mm diameter, 230 v primary, 12v secondary" , but I have no clue about the wiring. I'm not understanding how the Black + Yellow wires grouped in pairs can provide 240v and 12v...? (I'm assuming Brown + Blue are for the 240v input supply?
2. ILP TRANSFORMERS - 9T029 (that's all i have...?) From online research, I "think" this model (with having a "9" prefix) could be a 625VA , but no clue on wires V outputs?
(5 x pairs of wires) - Has, 2 x pairs of Red + Blue, then 2 x Pink, then 2 x pairs of Grey + Yellow paired)
3. ILP TRANSFORMERS - 9T631 0545 s/n506. Again, from online research, I "think" this model (with having a "9" prefix) could also be a 625VA , but no clue on wires V outputs?
(4 x pairs of wires) - Orange and Brown seem to be 'sleeved together' on each pair, then Red + Blue paired, and Grey + Yellow paired)
Hoping someone with prior knowledge can assist with, 1. How to test before using any of them, and 2. Wiring colours input/output voltages, for each transformer...?
Cheers guys
Basically, I've built myself a 'Dim Lamp Isolating box' for testing vintage devices and other power supplies (without blowing them up , or myself) and I need a 240v in , 240v out toroidal (isolation) transformer to drop into the middle of it (see image of my freshly made scary looking death box below).
Problem is, none of the transformers came with wiring diagrams and there are LOTS of pretty coloured wires sticking out, and I have no clue what they all do, as I have never even seen one before now. But, I'm hoping someone here does....
Dim Lamp Isolator (aka, The Box of Death)
(has 4 switchable test lamps, LED display, fuse, added trip switch, socket, and TEST/LIVE 'bypass' switch)
The last piece of the build-puzzle is the 'Isolation transformer', so I bought 3 x different cheap eBay toroidal transformers in the hope that at least one has the requirements for what I need. (i.e. basically only need, 240v AC in and 240V AC out). But the problem is, I think these transformers are so old there are no schematics in Google to be found.
These are the toroidal transformers in question:
1. AMETHYST DESIGNS LIMITED - AD3285T TT3001 0107 (info from seller was; "300va transformer 3.5kgs and 120mm diameter, 230 v primary, 12v secondary" , but I have no clue about the wiring. I'm not understanding how the Black + Yellow wires grouped in pairs can provide 240v and 12v...? (I'm assuming Brown + Blue are for the 240v input supply?
2. ILP TRANSFORMERS - 9T029 (that's all i have...?) From online research, I "think" this model (with having a "9" prefix) could be a 625VA , but no clue on wires V outputs?
(5 x pairs of wires) - Has, 2 x pairs of Red + Blue, then 2 x Pink, then 2 x pairs of Grey + Yellow paired)
3. ILP TRANSFORMERS - 9T631 0545 s/n506. Again, from online research, I "think" this model (with having a "9" prefix) could also be a 625VA , but no clue on wires V outputs?
(4 x pairs of wires) - Orange and Brown seem to be 'sleeved together' on each pair, then Red + Blue paired, and Grey + Yellow paired)
Hoping someone with prior knowledge can assist with, 1. How to test before using any of them, and 2. Wiring colours input/output voltages, for each transformer...?
Cheers guys
I suggest you watch a few of the you tube videos that already show you how to identify primary and secondary windings of a transformer. You'll need a DMM. I would start with your simplest transformer, the Amethyst (or even something smaller, simpler that you have around the house/bench for practice). Once you have identified continuity and the resistance of your windings, then you are well on your way to identify which wires are on the primary side and which wires are on the secondary side. Then you can proceed to test them with a low voltage source or variac if you know what you're doing (be safe!).
This way you can prove what the turns ratio(s) of the transformer is/are which will be further proof for you. As an example, a transformer with 230V on one side and 12V on the other side has a turns ratio of 19.17:1. Obviously a transformer with 240 on one side and 240V on the other side has a turns ratio of 1:1.
But be very careful, this can be dangerous if you unclear on what to do, hence my recommendation to watch a few you tube videos. The above video linked is a good start.
Best,
Anand.
This way you can prove what the turns ratio(s) of the transformer is/are which will be further proof for you. As an example, a transformer with 230V on one side and 12V on the other side has a turns ratio of 19.17:1. Obviously a transformer with 240 on one side and 240V on the other side has a turns ratio of 1:1.
But be very careful, this can be dangerous if you unclear on what to do, hence my recommendation to watch a few you tube videos. The above video linked is a good start.
Best,
Anand.
Welcome to the forum!🤝
Be very careful to working with mains voltage!
It looks like none of the transformers you have are isolation transformers!
My suggestion is to go ahead and complete your dim bulb tester without the isolation transformer, you can always install it later. The DBT can be used to test these transformers.
Now you can connect the transformer to the Dim Bulb Tester with a 40 Watt or lower Incandescent bulb, measure the secondary winding output voltage and compare the primary winding input voltage (it should be on your DBT's LED display), the ratio will tell you the actual output voltage if connect directly to 240V mains.
Be very careful to working with mains voltage!
It looks like none of the transformers you have are isolation transformers!
My suggestion is to go ahead and complete your dim bulb tester without the isolation transformer, you can always install it later. The DBT can be used to test these transformers.
Measure its resistance with a DMM, the pair of wires with higher resistance should be the 240V primary winding, my guess is the Brown + Blue pair are have higher resistance and for the 240v input.1. AMETHYST DESIGNS LIMITED - AD3285T TT3001 0107 (info from seller was; "300va transformer 3.5kgs and 120mm diameter, 230 v primary, 12v secondary" , but I have no clue about the wiring. I'm not understanding how the Black + Yellow wires grouped in pairs can provide 240v and 12v...? (I'm assuming Brown + Blue are for the 240v input supply?
Now you can connect the transformer to the Dim Bulb Tester with a 40 Watt or lower Incandescent bulb, measure the secondary winding output voltage and compare the primary winding input voltage (it should be on your DBT's LED display), the ratio will tell you the actual output voltage if connect directly to 240V mains.
Measure the relative resistance of all wires and report back.
I'd be wary of using transformers that you don't know the specifications of. Both voltage and power ratings vary widely. And on that note, just to put another worry to bed, are you actually 'sure' these are isolation transformers? Just that on my small phone screen at least some look like they could be step-down transformers.
But anyway, a basic isolation transformer has two wires in and two out, of the same diameter. Some may have a third wire in for an earth shield. Unfortunately in reality many are made to offer multi-voltage in and/or out options, so these can have their primary and/or secondary windings tapped in multiple places (so multiple wires). Some may even have more than one secondary winding.
You can build a map of the primary and secondary winding(s) based on what wire is connected to what and then the relative impedence or resistance between them. If you are competent to do so safely, and can identify at least the primary windings you could potentially connect to a supply and measure secondary voltages. Current capability and/or duty rating would be a guess based on overall size and conductor area.
I don't know your experience level so you must judge for yourself and take suitable care with whatever you try.
But anyway, a basic isolation transformer has two wires in and two out, of the same diameter. Some may have a third wire in for an earth shield. Unfortunately in reality many are made to offer multi-voltage in and/or out options, so these can have their primary and/or secondary windings tapped in multiple places (so multiple wires). Some may even have more than one secondary winding.
You can build a map of the primary and secondary winding(s) based on what wire is connected to what and then the relative impedence or resistance between them. If you are competent to do so safely, and can identify at least the primary windings you could potentially connect to a supply and measure secondary voltages. Current capability and/or duty rating would be a guess based on overall size and conductor area.
I don't know your experience level so you must judge for yourself and take suitable care with whatever you try.
thanks.
I built the Dim Lamp isolator based on this Youtube video and schematic. dim lamp build and schematic
In it, its shown that any toroidal transformer will do as long as it can supply 240v in and out ? or have i got that bit completely wrong ?
I don't want to damage any of the transformers by connecting it up wrongly inside the Dim Lamp box, which is why I came here to 100% make that happen.
im getting even more confused watching videos lol.... for example with my AMETHYST DESIGNS LIMITED - AD3285T shown above.
Is it not as described when I bought it ? 240v out and 12v out ? and is it in fact just 240v in, and 2 x 12v out (since there are 4 wires output ?)
This is what's confusing as I have been basing my understanding of the wires visible, on the sellers description...
cheers
I only need one of these to give me 240v in , and 240v out. The other outputs will be terminated out of use.
will test with DMM shortly (have an RCD socket right at the source
)
I built the Dim Lamp isolator based on this Youtube video and schematic. dim lamp build and schematic
In it, its shown that any toroidal transformer will do as long as it can supply 240v in and out ? or have i got that bit completely wrong ?
I don't want to damage any of the transformers by connecting it up wrongly inside the Dim Lamp box, which is why I came here to 100% make that happen.
im getting even more confused watching videos lol.... for example with my AMETHYST DESIGNS LIMITED - AD3285T shown above.
Is it not as described when I bought it ? 240v out and 12v out ? and is it in fact just 240v in, and 2 x 12v out (since there are 4 wires output ?)
This is what's confusing as I have been basing my understanding of the wires visible, on the sellers description...
cheers
I only need one of these to give me 240v in , and 240v out. The other outputs will be terminated out of use.
will test with DMM shortly (have an RCD socket right at the source
)
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I would seriously reconsider doing business with transformer companies that do not bother to identify the leads on the label.
If they also do not give you the proper lead identification when asked, then they do not deserve your business.
They do seem to be able to compose legal disclaimers at length, with no problem whatsoever. Think about that.
If they also do not give you the proper lead identification when asked, then they do not deserve your business.
They do seem to be able to compose legal disclaimers at length, with no problem whatsoever. Think about that.
Doesn't look good, if 'OL' means very high resistance.
But also 'surely' those black and yellow conductors are much bigger than the input brown & blue ones? The secondary winding on the toroid look chunky, too. If so, that indicates a higher current capacity on the secondary winding, and therefore also a lower voltage - i.e. it would be a step-down transformer. Step-down transformers are the most common type and (just in case you don't realise) these don't offer mains voltage output.
TBH I'm quite concerned that you don't yet understand the basics, which is potentially very dangerous when working with high voltages. Learning is no bad thing, but take great care of your safety as you go.
But also 'surely' those black and yellow conductors are much bigger than the input brown & blue ones? The secondary winding on the toroid look chunky, too. If so, that indicates a higher current capacity on the secondary winding, and therefore also a lower voltage - i.e. it would be a step-down transformer. Step-down transformers are the most common type and (just in case you don't realise) these don't offer mains voltage output.
TBH I'm quite concerned that you don't yet understand the basics, which is potentially very dangerous when working with high voltages. Learning is no bad thing, but take great care of your safety as you go.
transformer was sold to me as a, "300va transformer, 3.5kgs and 120mm diameter, 230v primary, 12v secondary"....
The black and yellow insulated wires are 'solid copper' , and much thicker than the Brown and Blue wires. They are not further insulated inside the yellow or black insulation.
So... its looking like this one is no use as its probably just 12v ac out, correct ?
Should we now move along to the next transformer ?, i.e. iLP TRANSFORMER - 9T029
Shall i post here the DMM readings i get from it ?
thanks
The black and yellow insulated wires are 'solid copper' , and much thicker than the Brown and Blue wires. They are not further insulated inside the yellow or black insulation.
So... its looking like this one is no use as its probably just 12v ac out, correct ?
Should we now move along to the next transformer ?, i.e. iLP TRANSFORMER - 9T029
Shall i post here the DMM readings i get from it ?
thanks
From the image, I suspect these wires are enameled wires, please clean off part of them with a knife or sandpaper and then measure again. I guess the two wires in the black and yellow tubing are two separate pairs of secondary windings (12V+12V?).
Please!
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ok, so here are the remaining 2 x transformers Ω readings
iLP TRANSFORMER - 9T029
RED + BLUE - OL (on both pairs)
GREY + YELLOW - OL (on both pairs)
PINK - 1.8Ω
iLP TRANSFORMER - 9T631
RED + BLUE - OL
GREY + YELLOW - OL
BROWN + ORANGE - 1Ω (on both pairs)
Are these then safe to connect to mains to measure output voltages ?
Do i need to join any 9T029 wires together ? (shown below) i.e. Blue + Blue, Brown +Brown , to mains N+L?
iLP TRANSFORMER - 9T029
RED + BLUE - OL (on both pairs)
GREY + YELLOW - OL (on both pairs)
PINK - 1.8Ω
iLP TRANSFORMER - 9T631
RED + BLUE - OL
GREY + YELLOW - OL
BROWN + ORANGE - 1Ω (on both pairs)
Are these then safe to connect to mains to measure output voltages ?
Do i need to join any 9T029 wires together ? (shown below) i.e. Blue + Blue, Brown +Brown , to mains N+L?
If I am understanding you correctly - none of those will work as isolation transformer for your dim bulb/isolator.
For an isolation transformer, you need two sets of windings - one pair of wires for 240V input, and another pair for 240V output. Those ones you have are 12V output.
I might also add that you really need to know what you are doing when using an isolation transformer - for example if you have your device under test powered through it, (with no earth connection) and you then connect test equipment that is earthed (eg the ground probe of a scope) then you have lost the protection that the isolation gives you.
I'd also add that decent sized isolation transformers are hard enough to come by.
Your AMETHYST DESIGNS LIMITED - AD3285T - most likely you aren't getting a resistance reading on the secondary because those wires are enamelled. You need to scrape away the enamel on each end to reveal the shiny bare copper and then you will likely find a resistance. This transformer will only give you 12Vac output - not the 240Vac you are looking for.
Finally - this link might help you decipher the ILP transformer.
https://davidmager.co.uk/index_htm_files/ILP transformers 2 .jpg
For an isolation transformer, you need two sets of windings - one pair of wires for 240V input, and another pair for 240V output. Those ones you have are 12V output.
I might also add that you really need to know what you are doing when using an isolation transformer - for example if you have your device under test powered through it, (with no earth connection) and you then connect test equipment that is earthed (eg the ground probe of a scope) then you have lost the protection that the isolation gives you.
I'd also add that decent sized isolation transformers are hard enough to come by.
Your AMETHYST DESIGNS LIMITED - AD3285T - most likely you aren't getting a resistance reading on the secondary because those wires are enamelled. You need to scrape away the enamel on each end to reveal the shiny bare copper and then you will likely find a resistance. This transformer will only give you 12Vac output - not the 240Vac you are looking for.
Finally - this link might help you decipher the ILP transformer.
https://davidmager.co.uk/index_htm_files/ILP transformers 2 .jpg
Isolation transformers are much less common than the step-down or step-up types simply because most power transformers are used to get a different voltage than the line voltage.
So the chances of getting the right used one from eBay are slim, unless the the part numbers / specs can be verified with a manufacturers data sheet.
It's been my experience many eBay sellers of used parts don't really know the specs for what they're selling.
So the chances of getting the right used one from eBay are slim, unless the the part numbers / specs can be verified with a manufacturers data sheet.
It's been my experience many eBay sellers of used parts don't really know the specs for what they're selling.
woodturner-fran,
You (and others), were correct about the wire varnish. it was on that thick I hadn't scraped enough away to make contact. cheers.
That AD3285T transformer does now work, but has 12v output, so useless for my task.
You also kindly provided the same sheet I had originally used to "guess-timate" if the ILP transformers might work. I searched ebay for ones that where in the "9" prefix-code range (or 625VA range), thinking it might work, especially the 93029 one (having 220v on secondary)... I know Mine is marked 9T029 , I had hoped it would be close enough to work given that it had 'two sets' of Red and Blue wires. But am just not sure how to test it properly without damaging it (as it might be 110v input).
93029 has 220v on secondary
https://davidmager.co.uk/index_htm_files/ILP transformers 2 .jpg
What is the safest way to connect the 9T029 up to the mains without damaging it ? (Sadly, I dont have a 110V source (or Variac), and i only have an RCD socket in place for everything I do).
Do i connect just one set of Red and Blue to the mains ? if yes, which set ?
cheers
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I just tested it on the mains (240v). SO, if i connect either set of Red and Blue to the mains, i do get 240v on the Grey and Yellow wires from the same grouping of wires. No voltage on the PINK wires when either set of Red+Blue are connected to mains ?
what can be deduced from these findings ? thanks
i.e.
what can be deduced from these findings ? thanks
i.e.