Transformer question: hot / neutral...

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Hello
My transformers, made by toroidy.pl, are all 250V models (single primary). They‘re both the same color, so connecting them is more or less a breeze.

But, does it matter which wire gets the hot and which the neutral connection? And if it makes a difference, how would I find out which one goes where?

Many thanks
David
 
Hi David,

I think this doesn't matter that much, for myself I would find the inner End of the Transformer to be the HOT wire.

but there is another problem I see for you which could be much worse.

In Swiss we have 99% of hoseholds using 220 volts, and as I know there are only little fluctuations in the outlets. Most times it will be 220 Volts.
Now you are using a Transformer with 250 Volts. it doesn't matter what secondary Voltage you wish to have, only that much: Connecting a 250Volts Transformer to to a 220 volts net, you will loose Secondary voltage. Make sure that you get the right amount of Volts at the secondary from your Transformer.

Example: you would like to get 30Volts AC from a 220 Volts transformer but you have only that 250Volts one. Then you need to calculate the actual output of that 250 Volts so that you know how much you will lose.

30:250= 0.12 x 220 = 26.4VOLTS AC you will get with that Configuration.. if you need to get 40 Volts plus DC 30x1.414=42.42 Volts
Then this is Sure not enough.

Because you will get only 26.4x1.414=37.32 VOLTS looking at it in percentage, then it's 12%! which you will get less.
But this is just my 5 cents...in that matter. if it makes any importance.
Regards Chris
 
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In Swiss we have 99% of hoseholds using 220 volts, and as I know there are only little fluctuations in the outlets. Most times it will be 220V...

Thank you very much for this hint.
Until now, I have been very lucky although I blindly trusted the manuals/recommentations/threads... [emoji28]

Just a little correction I might add: swissgrid (our national power-dealer :) ) converts to 230V / 400V, 220/380 was „our“ standard some time ago.

Still, I shall have a look on that when I‘ll need more xformers.

Best wishes & thanks again!
David
 
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transformers wound for 250 Vac primary voltage?

Do toroid windings have an inner and an outer end indeed?

Aah, my bad, typo! Just looked up, they are indeed 230V ... don't know why or how I came to 250V :eek:

as to the inner / outer end, don't know, but seems logical. Most probably so, the winding has a start and an end, just like a sausage. How to deal with it, well, beats me...
 
Might not be extremely significant with a toroid, but I always test my transformers for the optimal lead to consider neutral. The one with the highest stray capacitance to core/other windings should be wired to the neutral. This is easily tested with a line cord and AC voltmeter (can't use a capacitance meter). Somewhere in this forum is a process I documented.

Essentially, energize the primary and measure voltage between core and ground (earth). Other windings tied to core. Repeat for the opposite polarity. The one with highest stray capacitance will provide the higher voltage to ground.
 
Depends where and when.

Thank you very much for this hint.
Until now, I have been very lucky although I blindly trusted the manuals/recommentations/threads... [emoji28]

Just a little correction I might add: swissgrid (our national power-dealer :) ) converts to 230V / 400V, 220/380 was „our“ standard some time ago.

Still, I shall have a look on that when I‘ll need more xformers.

Best wishes & thanks again!
David


I just measured the power here in my Restaurant in BERN Bümpliz using Digital Meter 219Volts. Measured at the MAIN FUSE.!
On our three phase Oven 380 Volts and not one Volt over it.

230 Volts are still 20 Volts under the spec of that transformer. So the transformer does not deliver full Power. it's still 8% of the should be.

And I know the specs of Swiss electric very well.
If this would be a switching, I wouldn't dare to comment. But here we are talking about transformers. Not the same as a switching, transformers NEVER EVER bring the Power which they are designed too. In best case *95%*and then you have a good one..
It also depends what for you use it.

BTW I use Hamilton Transformers from CANADA.


Enjoy weekend and good build.
Regards
Chris
 
Toroids and its whereabouts

May I ask you why you've got your transformers wound for 250 Vac primary voltage? That's a bit ... unusual, I'd say.

Do toroid windings have an inner and an outer end indeed?

Best regards!


I meant to have seen when unwound a defect Toroid from China, that it had two layers, as soon there are two layers then you will certainly have an inner and an outer winding, and also a inner and outer end, at least for me.

But may Chinese made a mistake, who knows..

If you have a old no more used toroid, then just take a look at it take off the plastic and unwind it...

If not let me know, I'm happy to take some pictures while unwinding a toroid.


And you know, a Toroid has a Primary and a Secondary Layer.. As far as I know those are on top of each other.



Regards Chris
 

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I just measured the power here in my Restaurant in BERN Bümpliz using Digital Meter 219Volts. Measured at the MAIN FUSE.!

And I know the specs of Swiss electric very well.

transformers NEVER EVER bring the Power which they are designed too.

Oops, then it seems swissgrid is bragging about 230V... i never measured it...

And as I said before, i typoed on the 250V, my toroidy is a 230V one. Still ≈5% missing, but it’s working perfectly, delivering 24.6 V at the PSU-output, all good. I maybe should attempt to check its amperage then just to know what’s in it.

Hamilton... never heard of, which means nothing. They’re good I presume?
 
Yea so far the best I could buy..Sorry about the misspelling of the name, it's HAMMOND.
Getting old..

I use in my amps two Transformers, 1 per side. and this is the first transformer which keeps the VOLTAGE. all other I bought losing volts when I switch on the Amplifier.
its a steady of 38Volts @ 5.06 Amps Idle. if i remove the fuses it neither goes up or down, just keeps its 38 Volts.+- you can get it by Farnel.ch
Yea I saw that about the wrong Voltage too late sorry about.. Sometimes 1 or 2 Volts making a big difference, you will notice this difference best when building amplifiers.

And the Steady output is missing because to weak Transformers..

Enjoy Weekend there in Luzern.
 
Yea, living in Toffen*Gürbetal* but have my Restaurant in Bümpliz.
Just was curious about the electricity, so this morning I measured another Power Outlet in my Home(two family house), Kitchen where nothing else in connected on that Wall Outlet, and the meter read: 224Volts. BTW this outlet is secured with a 16amp fuse, means 3680W or 3.68KW, a lot just for an Wall outlet, calculated with 230Volts..

So from there to main Fuses we have about 20 meter Cable, at least, so I think this 230 Volts they are supposedly to deliver is to assure that the consumer gets at least the needed 220 volts.
But to make sure that this is more than only suspicion, I have a friend who is electrician here close to my restaurant, going to ask him next week, what the fact are of this.
cheers..
 
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@ myleftear
I have asked my friend the electrician, and he told me that it is depend of where someone live and ofr the rest, read answer #14Mark Tillotson answer.

My friend sayd about the same as Mark, in the citys it is suppose to be above 230 not much thou.. whatever this means.



Cheers


This probably means that if the gear is working we shall be happy... or so...
[emoji1744]
(Voltage may vary between nearly 220 and 230 V...)

Have a nice evening!
:cheers:
 
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