Use of the word "transformer"

[ericmark]

Another thread raises a very good reason for not calling SMPU ( or any other electronic power convertor ) a transformer.

Provided it is not overloaded or other wise abused a traditional wound transformer has very little risk of failing and becoming a fire hazard. An electronic convertor has several components which age and will at some point in time fail. The failure of a single component in an electronic power convertor can, depending on the quality of build, create a fire hazard, even a good quality unit could become a fire hazard depending on which component(s) have failed.

A door bell transformer fitted in 1952 is still in use, a few door bells have been worn out but the transformer is still in good working order.

Oil filled transformers do present health and safety issues which are not present with the welding inverter which replaced them. Think they are called PCB's and in spite what Terry Pratchett wrote that does not mean particular crunchy bits.

 

[ericmark]

Don't all switching power supplies with a 230/240V AC input invariably contain a transformer? It's difficult to achieve the necessary isolation and fault protection otherwise.
They just have extra electronics to run it at a higher frequency and regulate the output.

A switched mode power supply does not NEED to change the frequency, you can transform to approximately the voltage required and then use the switch mode system to regulate the output. Not a normal way of doing it, but switch mode only means the mark/space ratio is altered to adjust the output. As to if using a capacitor to reduce power rather than a transformer would give the isolation required is up for debate. But even with a transformer because the output is floating there is normally a voltage between the output and earth which can be quite high, however the current to earth is very low.

I personally think the frequency range should be declared on data sheets, there was a picture of a GU10 LED lamp which had 50 Hz written on it. One does expect 50 Hz into a transformer will give 50 Hz out, but with "Electronic transformers" this is not the case. I was I admit surprised to see 50 Hz written on a lamp. The Screwfix advert said transformer not required which raises the question of how you get a 12 volt 50 Hz supply without a transformer? I suppose in theroy you can use a capacitor to drop the voltage, however although possible I know of no device which actually uses that method outside of the lamp package.

 

[Edddd]

Yes, I believe you could do it with a capacitor too. You would have to use a high frequency in that case so that the capacitor would have sufficient impedance to isolate the 50Hz.
A high frequency switch capacitor circuit would also have exactly the same benefit as a high frequency transformer circuit: the capacitor/transformer is much smaller for a given power transfer.

Anyway, whilst in theory a SMPS does not need to contain a transformer, in practice - for the applications we are talking about - it is just an electronically-managed transformer.

 

[JohnW2]

A switched mode power supply does not NEED to change the frequency, you can transform to approximately the voltage required and then use the switch mode system to regulate the output.

Yes, one can do that - but if most of the 'transforming' is done at 50Hz, then one is back to a big and heavy transformer, thereby negating one of the greatest attractions of the SMPSU.

Kind Regards, John

 

[EFLImpudence]

I have not agreed that it "shall be limited".

Yes, you have. You are saying that something which does the same job by a different method should be called something else.

I am talking about what I believe probably would have been better (and less potentially confusing), but (unlike winston) accept what has happened, doubt that it is reversible and therefore see no point in 'going on about it'.

Stop going on about it then.

Things obviously evolve and, as you say, if the functionality remains much the same, then the same word can reasonably continue to be used.

You are saying it shouldn't.
240VAC in 12VAC out - transformer - however it is achieved.
240VAC in 12VDC out - transformer- however it is achieved.

Certainly any current-day technological item (TV, telephone or whatever) will be completely unrecognisable 'within' in comparison with items of similar functionality a few decades ago, yet it remains totally reasonable to continue using the same words, since (all) the items have changed/evolved.

Make up your mind.

However, my point is that, in the case we are discussing, the items have not (all) changed/evolved but, rather, something different has appeared in addition to what the item original was (and still is).

So?

The word "transformer" had a specific technical meaning for many decades,

So? (I suspect it was not originally a stand-alone word but don't know.)

relating to a component which still exists and still needs to be talked about today.

So?
Is there only ONE kind of TV, telephone or whatever?

If (as with TVs, telephones etc.) we had merely seen a technological evolution which had resulted in (all) transformers having evolved into something very physically different but with similar functionality (i.e. if wire-wound transformers had 'become extinct' as a result of that evolution process), then it would probably be reasonable to use the old word for whatever (all) such items had evolved into. However, given that wire-wound transformers do still exist, and do still need to be talked about, the situation is, IMO, very different.

Then you will have to call them w-w transformers.

You are relying heavily on dictionary definitions of "transformer"

So should you. That's what the word means.

but, if one took those definitions literally, we would describe such things as kettles, ovens, 'light bulbs' and loudspeakers as "transformers", but I assume that you would not advocate that.

Then you would have to distinguish between which you want by calling them kettles, ovens, 'light bulbs' and loudspeakers.
I think you're being silly trying to justify the unjustifiable.

In fact, other than the more recent use in relation to toys and the description of people (or groups of people etc.) as "transformers", I can't say that I have seen the word being used to describe anything which 'transforms' other than per the electrical definition.

You mean the same as 'telly' is a television and none of the other 'teles' and 'phone' is a telephone and none of the other 'phones'?

 

[stillp]

240VAC in 12VDC out - transformer- however it is achieved.

I hate to agree with Winston, but I wouldn't call that a transformer.
PSU, power supply, transformer-rectifier...

 

[EFLImpudence]

I know but the voltage has been transformed.

That's the whole problem with a specific item being called something that means something else.

 

[JohnW2]

Yes, you have. You are saying that something which does the same job by a different method should be called something else.

I certainly haven't said 'shall', and not even 'should' - merely that, IMO, it would have been better if the use of language had been different.

You are saying it shouldn't. 240VAC in 12VAC out - transformer - however it is achieved. 240VAC in 12VDC out - transformer- however it is achieved.

You cut my quote short, leaving off "... (all) the items have changed/evolved.". From that, and from what I subsequently wrote, you surely must have understood what I was saying - namely that it is reasonable to use the old word IF (as with TVs and telephones) evolution has been such that everything has evolved and the "things of old" no longer exist to any significant degree and hence no longer needed to be talked about (other than in a historical context, when further explanation could be given).

Then you will have to call them w-w transformers.

Exactly my point. There still are plenty of wire-wound transformers around, and we need to be able to talk about them clearly. The fact that the word "transformer" has been 'hijacked' means that we now have to qualify the word if we want it to have the same meaning as it did a few decades ago.

You mean the same as 'telly' is a television and none of the other 'teles' and 'phone' is a telephone and none of the other 'phones'?

Colloquial English could have evolved differently, but it didn't. Although "telly" might have (but didn't) come to be used to refer to any number of other things, how often have your heard someone say In everday conversation) "telly" when they were talking about something other than a television? In my experience, other than in a few specialised contexts, that's extremely rare.

Kind Regards, John

 

[stillp]

So has the frequency!

 

[JohnW2]

I hate to agree with Winston, but I wouldn't call that a transformer.
PSU, power supply, transformer-rectifier...

I think that many people (if not EFLI) would agree that it really is going a bit too far into the realms of potential confusion to describe something which converts AC to DC as a transformer. Even parts of EFLI's argument would probably not accept that since, even in the pre-SMPSU days, no-one would have dreamed of referring to something which converted AC to DC as a transformer - so he could not talk about 'unchanged functionality'. Such things were called PSUs back then (or maybe 'AC to DC converters', although that may be taken to imply no voltage change), just as (IMO) they still should be today.

Kind Regards, John

 

[JohnW2]

So has the frequency!

Does that somehow relate to my immediately preceding post, or whT? Some indication of context is always helpful.

Kind Regards, John

 

[EFLImpudence]

I certainly haven't said 'shall', and not even 'should' - merely that, IMO, it would have been better if the use of language had been different.

Obviously.

You cut my quote short, leaving off "...

It's in the next quote.

(all) the items have changed/evolved.". From that, and from what I subsequently wrote, you surely must have understood what I was saying - namely that it is reasonable to use the old word IF (as with TVs and telephones) evolution has been such that everything has evolved and the "things of old" no longer exist to any significant degree and hence no longer needed to be talked about (other than in a historical context, when further explanation could be given).

I don't see the difference.

Exactly my point. There still are plenty of wire-wound transformers around, and we need to be able to talk about them clearly. The fact that the word "transformer" has been 'hijacked' means that we now have to qualify the word if we want it to have the same meaning as it did a few decades ago.

The hi-jacking was the original decision to call them transformers - if it was not an abbreviation of a longer name.

Colloquial English could have evolved differently, but it didn't. Although "telly" might have (but didn't) come to be used to refer to any number of other things, how often have your heard someone say In everday conversation) "telly" when they were talking about something other than a television? In my experience, other than in a few specialised contexts, that's extremely rare.

That was my point in answer to your suggestion that a lot of things transform something.

 

[EFLImpudence]

I think that many people (if not EFLI) would agree that it really is going a bit too far into the realms of potential confusion to describe something which converts AC to DC as a transformer.

Has the voltage not been transformed?

 

[stillp]

Does that somehow relate to my immediately preceding post, or whT? Some indication of context is always helpful.

Kind Regards, John

Yes, your post wasn't there when I posted a response to EFLI at #22.

 

[JohnW2]

It's in the next quote.

Apologies - I missed that. However, the fact that you actually quoted it means that I would have expected you to understand what I was saying.

The hi-jacking was the original decision to call them transformers - if it was not an abbreviation of a longer name.

As I've implied before, I really don't think we should be quibbling today about what happened to language some 150, or whatever, years ago. Given scientific and technological advances during the period of the Industrial Revolution, vast numbers of new (technological and scientific) things had to be given names during the 18th and 19th centuries - and I think that a substantial proportion of those 'new names' represented (partial or complete) 'hijackings' of words that had previously had other meanings. You surely don't think that they were all 'wrong', do you?

Kind Regards, John