L6-20 Plugs convert to standard 240v?

[JohnW2]

Older equipment transformers, back in the days when the UK had several voltage standards, would have several adjustable voltage tappings to cope.

Indeed, but that is essentially (old) 'history'.

Equipment has to either be designed to work with a range of voltages, or a set voltage.

Sort-of - except that, in the real world (other than in some very specialised environments) there is not such a thing as a 'set voltage'. Given that there will always be quite a wide range of permissible supply voltages (such as 216.2 - 253V in UK), it makes no sense to design equipment such that it will not work satisfactorily with any voltage within that range.

Modern SMPSU supplied equipment can be designed to work with anywhere from 100 to 260v.

It can, and often is. Indeed, it could be designed to work over whatever range of voltages one wanted - but the range you mention covers virtually any supply voltage one would find anywhere in the world.

For the avoidance of doubt, I have come across motors with name plates specifying they are able to work on a range of voltages - that ability starts at the design stage. Others specify just a single voltage.

Yes - but, as above, when they "specify just a single voltage" they obviously don't mean to imply that it will only work at exactly that one voltage.

Kind Regards, John
Edit: typo corrected

 

[plugwash]

Even when devices specify a range of voltages, my understanding is that said range is a range of nominal voltages and tolerances are beyond that. So your "100V-240V" power supply will have an actual input range of more like 90V to 264V.

 

[JohnW2]

Even when devices specify a range of voltages, my understanding is that said range is a range of nominal voltages and tolerances are beyond that. So your "100V-240V" power supply will have an actual input range of more like 90V to 264V.

Even that is possible. However, the range Harry quoted (100-260V) is so wide (and often starts at 90V) as to encompass almost any actual voltage one is likely to encounter, in which case the nominal voltages are not particularly relevant.

I think that (nearly ) all of us understand that if a 'single voltage' is specified, the intended meaning is that the figure refers to nominal voltages, so if that 'single voltage' is within the range 220-240V, it effectively means that it will work satisfactorily anywhere where the nominal supply voltages is ("in the 200s") - which, in practice, means most places other than the US.

Kind Regards, John

 

[ericmark]

Indeed, but that is essentially (old) 'history'.
Sort-of - except that, in the real world (other than in some very specialised environments) there is not such a thing as a 'set voltage'. Given that there will always be quite a wide range of permissible supply voltages (such as 216.2 - 253V in UK), it makes no sense to dewsign equipment such that it will work satisfactorily with any voltage within that range.
It can, and often is. Indeed, it could be designed to work over whatever range of voltages one wanted - but the range you mention covers virtually any supply voltage one would find anywhere in the world.
Yes - but, as above, when they "specify just a single voltage" they obviously don't mean to imply that it will only work at exactly that one voltage.

Kind Regards, John

Think some typo errors there, "it makes no sense to dewsign equipment such that it will work satisfactorily with any voltage within that range." I think should have said "it makes sense to design equipment such that it will work satisfactorily with any voltage within that range."

There are some cases where the nominal voltage can be a problem, we tend to say 12 volt from 11.4 volt to 14.8 volt and motor vehicle stuff would take that range, but put a bulb designed for a SELV system in a house in a caravan and we likely have a problem when the caravan has a stage charger taking the voltage to 14.8 volt then floating at 13.4 volt, but with a low voltage domestic supply we expect the standard range, and there should be no problem within that range.

95 ~ 240 volt is common on devices, even when we know it can go to 254 volt, may be if we kept ringing manufacturers they would alter it to say 95 ~ 255 volt? But it is very unlikely to be a problem with a motor.

 

[bernardgreen]

In the good old days fluctuating voltages were dealt with using Iron–Hydrogen resistors

Iron–hydrogen resistors were used in the early vacuum tube systems in series with the tube heaters, to stabilize the heater circuit current against fluctuating supply voltage. In 1930s Europe it was popular to combine them in the same glass envelope with an NTC-type thermistor made of UO2 until 1936, known as Urdox resistor and acting as an inrush current limiter for the series heater strings of domestic AC/DC tube radios.

source https://en.wikipedia.org/wiki/Iron–hydrogen_resistor

 

[JohnW2]

Think some typo errors there, "it makes no sense to dewsign equipment such that it will work satisfactorily with any voltage within that range." I think should have said "it makes sense to design equipment such that it will work satisfactorily with any voltage within that range."

Yes, there is a typo - my apologies (now corrected). I could have worded it as you suggest, but what I had actually intended was (as now corrected):

"it makes no sense to design equipment such that it will not work satisfactorily with any voltage within that range."

There are some cases where the nominal voltage can be a problem, we tend to say 12 volt from 11.4 volt to 14.8 volt and motor vehicle stuff would take that range, but put a bulb designed for a SELV system in a house in a caravan and we likely have a problem when the caravan has a stage charger taking the voltage to 14.8 volt then floating at 13.4 volt, but with a low voltage domestic supply we expect the standard range, and there should be no problem within that range.

That's really rather different from a 'nominal voltage'. The upper parts of the 11.4V-12.0V 'range' we think about in relation to rechargeable 12V batteries exists only because those are the sort of voltages one expected to see whilst the battery is being charged. A non-rechargeable battery with a 'nominal' voltage of 12V would never have an actual voltage across its terminals which was appreciably greater than 12V.

95 ~ 240 volt is common on devices, even when we know it can go to 254 volt, may be if we kept ringing manufacturers they would alter it to say 95 ~ 255 volt? But it is very unlikely to be a problem with a motor.

Well, 253V in the UK. However, as plugwash said, when they label something as, say, 95V-240V, they are probably talking about nominal voltages, so are probably implying that voltage's up to well over 260V are OK.

Kind Regards, John

 

[Jackrae]

Not exactly relevant but when I worked in the food industry, some of the equipment we used was sourced in America and fitted with Baldor drive motors rated for 380v 60Hz
On 415v (as it was then) 50Hz it ran somewhat slower, (83% of rated speed) with 10% over-voltage, quite happily.

 

[Harry Bloomfield]

Yes - but, as above, when they "specify just a single voltage" they obviously don't mean to imply that it will only work at exactly that one voltage.

The US market is large. It costs more money for them to design and manufacture for 'foreign markets', so generally they do not. Were it me, I would ask them if it is acceptable to run them on a UK mains of 240v 50Hz, rather than take the risk.

 

[JohnW2]

Yes - but, as above, when they "specify just a single voltage" they obviously don't mean to imply that it will only work at exactly that one voltage.

The US market is large. It costs more money for them to design and manufacture for 'foreign markets', so generally they do not. Were it me, I would ask them if it is acceptable to run them on a UK mains of 240v 50Hz, rather than take the risk.

I don't really understand how your comment relates to mine which you quoted and are responding to. If a US manufacturer "specified just a single voltage", without considering 'foreign markets', the 'single voltage' they specified would surely be one which made it obvious that it wasn't suitable for 240V 50Hz, wouldn't it?

Kind Regards, John

 

[Harry Bloomfield]

I don't really understand how your comment relates to mine which you quoted and are responding to. If a US manufacturer "specified just a single voltage", without considering 'foreign markets', the 'single voltage' they specified would surely be one which made it obvious that it wasn't suitable for 240V 50Hz, wouldn't it?

I thought the manufacturer had in fact done that, by stamping 230v on the plate, rather than a range of voltages. 230v 50Hz would cover the EU, perhaps a larger market than the UK.

Anyway - it is up to the OP to risk it, or contact the manufacturer to approve the equipments use on the UK's 240v supply.

 

[BS3036]

I thought the manufacturer had in fact done that, by stamping 230v on the plate, rather than a range of voltages. 230v 50Hz would cover the EU, perhaps a larger market than the UK.

No - 230V would cover the EU and the UK, as both have a nominal voltage of 230V.

Possibly Harry is not aware that at the same time we changed our nominal voltage from 240V to 230V, the EU changed theirs from 220V to 230V.

 

[Harry Bloomfield]

No - 230V would cover the EU and the UK, as both have a nominal voltage of 230V.

Where does the plate indicate that the 230v is a nominal voltage?

It clearly doesn't, nor does it suggest a range of acceptable voltages - so the prudent thing to do is ask the manufacturer.

 

[JohnW2]

I thought the manufacturer had in fact done that, by stamping 230v on the plate, rather than a range of voltages. 230v 50Hz would cover the EU, perhaps a larger market than the UK.

As I said, the reality is that if all that appears on an appliance is a single voltage "in the 200s", then I think one can reasonably assume that they are talking about nominal voltages and that any voltage one could/would encounter in the the EU (and most of the non-US world) would be OK.

In the case of a few of the things which contain motors, the difference between 50Hz and 60Hz could make a difference, but one would hope that the manufacturer would be aware of that and would be explicit about what was required.

Kind Regards, John

 

[JohnW2]

Where does the plate indicate that the 230v is a nominal voltage?

If it gives just a single figure, then I think one safely assume that it is a 'nominal' figure.

You surely aren't suggesting that, if they just indicate "230V", they are saying that 229.9V or 230.1V would not be acceptable, are you?

Kind Regards, John

 

[Harry Bloomfield]

As I said, the reality is that if all that appears on an appliance is a single voltage "in the 200s", then I think one can reasonably assume that they are talking about nominal voltages and that any voltage one could/would encounter in the the EU (and most of the non-US world) would be OK.

In the case of a few of the things which contain motors, the difference between 50Hz and 60Hz could make a difference, but one would hope that the manufacturer would be aware of that and would be explicit about what was required.

Kind Regards, John

To be fair, the OP has not provided much information at all, as what this actual equipment is, but how difficult can it be, to simply ask the manufacturer if it is suitable for use on UK voltages?