Dimmable GU10

[winston1]

I was told that the transformers are the likely things that go for the MR16 halogens. We had these installed back in 2002.

You were told wrongly. Transformers rarely fail. Switch mode power supplies often fail and are frequently used for cheapness (in the short term).

Of course many MR16 halogen are 240 volt so no not require a separate supply.

 

[ban-all-sheds]

It is labelled wrongly. Yet another example of stupid manufacturers who don't know what they are selling.

 

[winston1]

So what. You have 4 examples of stupid manufacturers who don't know what they are selling.
Why didn't you also include those trying to sell plugtops, and digital aerials, or those that tell you to put a 3 amp fuse in line because they think it protects the appliance not the cable.?

 

[ban-all-sheds]

So what.

So:

1. They do transform voltage.
2. They are called transformers by the people who make them, sell them and buy them.
3. There are no dangers of people ending up with something which is not what they need.
4. A useful exercise for the reader would be to consider where the balance of stupidity lies .

 

[winston1]

So:

1. They do transform voltage.
2. They are called transformers by the people who make them, sell them and buy them.
3. There are no dangers of people ending up with something which is not what they need.
4. A useful exercise for the reader would be to consider where the balance of stupidity lies .

1. Yes, but not by electromagnetic induction, which is a requirement in the definition of a transformer.
2. We have already established that they are stupid and do not know what they are making/selling/buying.
3. There seem to be plenty of people on these forums who do just that and complain that their LEDs don't work properly.
4. By calling equipment by the wrong name.

 

[333rocky333]

You were told wrongly. Transformers rarely fail. Switch mode power supplies often fail .

It just appears to look that way because theres more of the latter in use nowadays.
In the 90s nearly all were toroidals, and i was changing 100s, many had overheated, blistered the cases and some even blown apart, there was no decent protection like on the new electronic jobs, so they resorted to fitting fuses on them and were a pain having to drag the things out to fit a new fuse when the lamps failed.
Many premises had fires due to the output leads shorting, i know of a boots shop in romford and a pub in harlow, where the outputs were wired in something like 1mm flex to unfused outputs, they shorted together due to the lamp heat melting the wires in the holder

 

[bernardgreen]

In the 90s nearly all were toroidals, and i was changing 100s, many had overheated,

Over heating suggests either overloaded and IR losses becoming too high or with some low grade units shorted turns.

there was no decent protection like on the new electronic jobs

Good quality SMPS may have "decent" protection but a lot of the SMPS unit on sale to the general public have no protection at all. A common failure is the electrolytic capacitor across the rectified AC mains ( 320 volts DC ) explodes inside the confined space and the PCB including the mains terminations is covered in conductive debris and the only current limit is the 6 amp MCB in the consumer unit.

 

[aptsys]

1. Yes, but not by electromagnetic induction, which is a requirement in the definition of a transformer.

Don't talk drivel. All of the illustrated SMPSUs use electromagnetic induction for the voltage conversion. The difference being that the transformer is a small ferrite core transformer with a high switching frequency rather than 50Hz. The output is still isolated and galvanic isolation is the only means to achieve this.

 

[bernardgreen]

All of the illustrated SMPSUs use electromagnetic induction for the voltage conversion.

Often the transformer is a 1 to 1 fed with high frequency chopped DC with an effective ( average ) voltage into the transformer that is the same as that required on the output

Those illustrated in this thread so far almost certainly do have a high frequency wound transformer between mains and output to achieve the galvanic isolation between mains input and ELV output. But not all SMPS have a transformer. Some have one side of the mains ( hopefully the Neutral ) connected directly to the 0v of the ELV output and a semi-conductor switch between the other side of the mains ( hopefully the Live ) and the positive of the ELV output. If the switch fails short circuit the output becomes 230 volt AC via a current liniting capacitor and/or resistor.

This arrangement is often used in multifuntion LED fairy lights where the lamps are permanently wired to the SMPS module and mains polarity is assured. ( by it being a plug top SMPS )

 

[ban-all-sheds]

1. Yes, but not by electromagnetic induction, which is a requirement in the definition of a transformer.

They transform a voltage. See #4.

2. We have already established that they are stupid and do not know what they are making/selling/buying.

No, they are making devices which transform a voltage and call them that. See #4.

3. There seem to be plenty of people on these forums who do just that and complain that their LEDs don't work properly.

If someone buys the wrong type of something it is not the maker's fault for calling it a type of something. See #4.

4. By calling equipment by the wrong name.

No....

 

[winston1]

A dropper resistor transforms voltage but no one called it a transformer. A SMPT is NOT a transformer even if it contains a small one.

 

[bernardgreen]

They transform a voltage. See #4.

They, SMPS, do nit transform a voltage, they change one type of supply into a different form of supply. typically 230 volt AC into 12 DC eff

No, they are making devices which transform a voltage and call them that. See #4.

if they only transform the voltage then how come the frequency is changed and the AC becomes DC

If someone buys the wrong type of something it is not the maker's fault for calling it a type of something. See #4.

You would say customer was a victim of fraud if the falsely described item they had bought was anything other than an SMPS mis named as a transformer

 

[winston1]

Don't talk drivel. All of the illustrated SMPSUs use electromagnetic induction for the voltage conversion. The difference being that the transformer is a small ferrite core transformer with a high switching frequency rather than 50Hz. The output is still isolated and galvanic isolation is the only means to achieve this.

A more polite way to say it would be what about the small transformer inside?

The answer of course is that that just because one of the components is a small transformer does not mean the whole thing is a transformer, any more than the whole thing could be called a capacitor or resistor.

 

[ban-all-sheds]

They, SMPS, do nit transform a voltage, they change one type of supply into a different form of supply. typically 230 volt AC into 12 DC eff

I'd say that changing 230V AC to 12V DC was making a marked change in the form, nature, or appearance of the voltage, wouldn't you?

if they only transform the voltage then how come the frequency is changed and the AC becomes DC

Because they transform it. They make a change to it. They change it's nature from AC to DC. They transform it.

You would say customer was a victim of fraud if the falsely described item they had bought was anything other than an SMPS mis named as a transformer

 

[bernardgreen]

I cannot find the document for the details ( and they may be restricted circulation )/

Around 2003 a company installed new lighting in a science laboratory. It was specified by the building services manager that the lighting was to be ELV supplied by a transformer. It was written as " a transformer " and not specifically as a "wound transformer and not an electronic transformer".

When the new lighting was switched on items of sensitive electronic equipment in the laboratory malfunctioned.

Spurious radiation from the several SMPS units was to blame.

Litigation ensued and blame was allocated between the company that installed the lighting ( they should have known SMPS were not compatible with the type of equipment used on the laboratory ) and the building services manager who was aware that SMPS would disrupt the operations in the laboratory and should have made that clear by stating no SMPS to be installed.