Electrical Engineering - Devices to convert 240 v, 50 H to 120v 60 Hz?

Author

Devices to convert 240 v, 50 H to 120v 60 Hz?

RedFox

2005-08-11, 10:21 pm

What are these called? and where could I buy them in various wattages, say
10w, 50 w, etc, or is it KVAs?

TIA

rf

TimPerry

2005-08-11, 10:21 pm

"RedFox" <RedFox@NoDen.con> wrote in message
news:ehSKe.4528$WD.1607@newsread1.news.pas.earthlink.net...
> What are these called? and where could I buy them in various wattages, say
> 10w, 50 w, etc, or is it KVAs?
>
> TIA
>
> rf
>

i would call it a power supply and an inverter.

you obtain a power supply that operates from 220 - 240 VAC @50 Hz. it
outputs 12 - 13.8 VDC.

the inverter then runs on 12 VDC and outputs 120 VAC @ 60 Hz

you might be able to find an all in one box somewhere but my guess would be
the price would be high and it probably will be a special order

John G

2005-08-11, 11:21 pm

"RedFox" <RedFox@NoDen.con> wrote in message
news:ehSKe.4528$WD.1607@newsread1.news.pas.earthlink.net...
> What are these called? and where could I buy them in various wattages,
> say
> 10w, 50 w, etc, or is it KVAs?
>
> TIA
>
> rf
>
What do you want to run?
You may not need to change the frequency.
--
John G

Wot's Your Real Problem?

RedFox

2005-08-12, 1:21 am

"John G" <Greentest@ozemail.com.au> wrote in message
news:42fc0256$0$32226$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>
> "RedFox" <RedFox@NoDen.con> wrote in message
> news:ehSKe.4528$WD.1607@newsread1.news.pas.earthlink.net...
> What do you want to run?
> You may not need to change the frequency.
> --
> John G
>
> Wot's Your Real Problem?

Thank you Tim and John.

Electronics - receiver, amplifier, speakers, tape units, cine projector, and
small power tools.

TIA

rf

John G

2005-08-12, 2:21 am

"RedFox" <RedFox@NoDen.con> wrote in message
news:IiVKe.4802$RS.1715@newsread3.news.pas.earthlink.net...
>
> "John G" <Greentest@ozemail.com.au> wrote in message
> news:42fc0256$0$32226$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
[color=darkred]
> Thank you Tim and John.
>
> Electronics - receiver, amplifier, speakers, tape units, cine
> projector, and
> small power tools.
>
> TIA

Some of those devices need a local (110v) wall wart just like the 240
volt one that came with them and most of the rest will more than likely
run from a 110 to 240 volt transformer and be happy with the 60 hertz.
It is really not possible to be sure without seeing and reading the name
plate on each device.
Or it may turn out cheaper to buy a local equivalent device.
--
John G

Wot's Your Real Problem?

Palindr☻me

2005-08-12, 6:21 am

RedFox wrote:
> "John G" <Greentest@ozemail.com.au> wrote in message
> news:42fc0256$0$32226$5a62ac22@per-qv1-newsreader-01.iinet.net.au...
>
>
>
> Thank you Tim and John.
>
> Electronics - receiver, amplifier, speakers, tape units, cine projector, and
> small power tools.
>
I am not sure whether you have 240v 50 Hz equipment that you
want to run off 120 volt or a 240 v supply that you want to
use to power 120 v equipment? You could have just moved to
your present posting time zone - or you could just be
preparing to move from it - so that doesn't help either.

Converting voltage is a doddle:

Many bits of electronics kit these days will work on either
- maybe with the need to slide a voltage selector switch on
the box.

Many use an external power brick and the manufacturer/ local
electronics shop can provide a suitable replacement.

You can buy "autotransformers" in various wattages values
from a few watts to a few kW. These typically have a
"normal" socket on them that you can just plug your foreign
unit in to. Your power tools may need one of these.

There are other converters - some which simply use a power
rectifier to allow 120v units to run off 240v. I wouldn't
use one with anything in your list..If the converter feels
very light, it is probably one of these.

Converting frequency is much more difficult and expensive.

Unfortunately your tape decks, record players and projectors
may need it because they may use drive motors with speed
determined by supply frequency. Sometimes they have
mechanical ways of allowing for 50 or 60 Hz - eg a sleeve
that can be fitted/removed from a shaft, two positions on a
pulley wheel. Or an alternative (often user-fitted) rotary
part from the manufacturer that can be fitted as a replacement.

Failing that - one option is to use a portable generator. I
know one person who shipped a generator home with everything
else. This probably won't apply in your case, but I thought
that I would mention it.

Otherwise, you need either inverters or rotary converters.
The latter are mostly for kW and tend to be expensive and
make a noise - but I have several government/army surplus
ones that only cost a few pounds and will probably last
longer than I will. They produce really excellent, low
noise, electrically isolated, outputs.

Inverters are electronic bits of kit that take the input
supply, convert it to dc and then rebuild a sine wave at the
right frequency and voltage. Some produce a pretty good sine
wave out - others don't. The problem with a poor sine wave
is that it produces harmonics that can be very audible and
practically impossible to get rid of, if using radio or
audio equipment. It isn't always obvious, from the technical
description, as to whether a particular inverter will be
good or bad, in this respect. You really need to try it.

They come in a wide range of power outputs and a very wide
range in cost.

So, basically, it would be best to go through everything and
reduce to a minimum that which really must have the "right"
voltage and frequency. Then consider replacing them! Then
buy an inverter(s) stating clearly what the intended purpose
is - in the UK, at least, that will allow you to return it
and get your money back, if it does produce too much
interference with your audio/radio.

--

Sue

furles@mail.croydon.ac.uk

2005-08-12, 12:21 pm

What makes and models of film projectors? Many of them can be changed
to run on the other frequency. Some tape recorders can also, e.g. by
moving a belt to a different step on a pulley.

RedFox

2005-08-15, 2:21 am

<furles@mail.croydon.ac.uk> wrote in message
news:1123856886.549599.199660@g44g2000cwa.googlegroups.com...
> What makes and models of film projectors? Many of them can be changed
> to run on the other frequency. Some tape recorders can also, e.g. by
> moving a belt to a different step on a pulley.

Thank you John G, Palindr?me and Furles, for the very helpful comments.

My film projector is German made so it should be ok, though I'm not sure how
it copes
with the frequency change. It's out of my reach at present so I can't look
at it. As Furles suggested, I have a DUAL turntable that has a voltage
switch 220-110 and a replacement pulley. The tape recorders I have not
looked closely at but will soon. With a VCR there is a double problem - the
TV format, in addition to the frequency difference. Another of the problem
pieces is a Sony receiver that has a plate mark of 110 v, 60 Hz and no
change possibility. I asked Sony about 220v 50 Hz and they said to use an
AVR, or something like that. I asked what they meant and didn't respond. I
did a search and came up with zillions of hits of all kinds.
Somehow I had expected fairly inexpensive 220 - 50 Hz => 11- 60 Hz for small
items around 20 watts but haven't identified any.

Thanks again.

rf.

Palindr☻me

2005-08-15, 7:21 am

RedFox wrote:
> <furles@mail.croydon.ac.uk> wrote in message
> news:1123856886.549599.199660@g44g2000cwa.googlegroups.com...
>
>
>
>
> Thank you John G, Palindr?me and Furles, for the very helpful comments.
>
> My film projector is German made so it should be ok, though I'm not sure how
> it copes
> with the frequency change. It's out of my reach at present so I can't look
> at it. As Furles suggested, I have a DUAL turntable that has a voltage
> switch 220-110 and a replacement pulley. The tape recorders I have not
> looked closely at but will soon. With a VCR there is a double problem - the
> TV format, in addition to the frequency difference. Another of the problem
> pieces is a Sony receiver that has a plate mark of 110 v, 60 Hz and no
> change possibility. I asked Sony about 220v 50 Hz and they said to use an
> AVR, or something like that. I asked what they meant and didn't respond. I
> did a search and came up with zillions of hits of all kinds.
> Somehow I had expected fairly inexpensive 220 - 50 Hz => 11- 60 Hz for small
> items around 20 watts but haven't identified any.

Well, domestic VCRs are effectively obsolete now anyway and new ones are
very cheap. But I would transfer the tapes to DVDs and move on.

For AVR, read autotransformer. OK, you can get autotransformers with
switched taps that act as an "Automatic Voltage Regulator" - to allow
for very variable utilitiy supplies. You probably won't need anything
that complicated or expensive and a simple 220 > 110 volt
autotransformer will do. Maplin (UK) have one rated at 100W:

http://www.maplin.co.uk/Module.aspx...=31899&doy=15m8

Note that these do NOT change the frequency - but only the voltage. So
typically it will change 220-50Hz => 110 - 50Hz

If the Sony receiver is also a mains-driven alarm clock - you will have
problems. It quite possibly won't keep accurate time. There is often a
link on the clock board inside that can be made or broken to allow for
mains frequency (much like the mechanical equivalent of a sleeve on a
shaft or a pulley change, as I suggested for mechanical kit) so it may
be possible to fix this - but the link is probably soldered and you need
someone used to working with asoldering iron on electronics, if you
aren't.

--
HTH
Sue

John G

2005-08-15, 7:21 am

"Palindr?me" <sb382638@hotmail.com.invalid> wrote in message
news:11g0nl21bg6s6b6@corp.supernews.com...
> RedFox wrote:
>
> Well, domestic VCRs are effectively obsolete now anyway and new ones
> are very cheap. But I would transfer the tapes to DVDs and move on.
>
> For AVR, read autotransformer. OK, you can get autotransformers with
> switched taps that act as an "Automatic Voltage Regulator" - to allow
> for very variable utilitiy supplies. You probably won't need anything
> that complicated or expensive and a simple 220 > 110 volt
> autotransformer will do. Maplin (UK) have one rated at 100W:
>
> http://www.maplin.co.uk/Module.aspx...=31899&doy=15m8
>
> Note that these do NOT change the frequency - but only the voltage. So
> typically it will change 220-50Hz => 110 - 50Hz
>
> If the Sony receiver is also a mains-driven alarm clock - you will
> have problems. It quite possibly won't keep accurate time. There is
> often a link on the clock board inside that can be made or broken to
> allow for mains frequency (much like the mechanical equivalent of a
> sleeve on a shaft or a pulley change, as I suggested for mechanical
> kit) so it may be possible to fix this - but the link is probably
> soldered and you need someone used to working with asoldering iron on
> electronics, if you aren't.
>
> --
> HTH
> Sue
>
Caution>>>>>>>
AUTOtransformers are not permitted in most 230volt countries because it
is possible to get your 110volt device connected to the 230volt hot and
a tap half way down instead of the neutral and a tap halfway up.
I would be very surprised if they are allowed in the UK but then I do
not know where you or the OP are.

Really the simplest answer to all this is to uy new devices at the new
location. (What a great excuse to update.)
--
John G

Wot's Your Real Problem?

Palindr☻me

2005-08-15, 10:21 am

John G wrote:
> "Palindr?me" <sb382638@hotmail.com.invalid> wrote in message
> news:11g0nl21bg6s6b6@corp.supernews.com...
>
>
> Caution>>>>>>>
> AUTOtransformers are not permitted in most 230volt countries because it
> is possible to get your 110volt device connected to the 230volt hot and
> a tap half way down instead of the neutral and a tap halfway up.
> I would be very surprised if they are allowed in the UK but then I do
> not know where you or the OP are.
>
> Really the simplest answer to all this is to uy new devices at the new
> location. (What a great excuse to update.)

"Most"? I hadn't realised that, would you like to list a few?

They are certainly widely available in the UK. If you would like to go
to rswww.com and search on "autotransformers" - you would find
everything from a few tens of watts single phase to rather larger three
phase.

The ones intended for "consumer" use have a permanent mains lead with a
moulded on plug - the UK plug is polarised and the problem that you
mention cannot happen unless the wiring infrastructure is incorrect.

--

Sue

Andrew Gabriel

2005-08-15, 10:21 am

In article <430068d7$0$4552$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
"John G" <Greentest@ozemail.com.au> writes:
>Caution>>>>>>>
>AUTOtransformers are not permitted in most 230volt countries because it
>is possible to get your 110volt device connected to the 230volt hot and
>a tap half way down instead of the neutral and a tap halfway up.
>I would be very surprised if they are allowed in the UK but then I do
>not know where you or the OP are.

There's no problem in the UK, as our mains supplies are polarised
and live/neutral distinction maintained into appliances.
Most other parts of Europe do not have polarised socket outlets though.

--
Andrew Gabriel

RedFox

2005-08-15, 4:21 pm

"Andrew Gabriel" <andrew@cucumber.demon.co.uk> wrote in message
news:430091c6$0$38038$5a6aecb4@news.aaisp.net.uk...
> In article <430068d7$0$4552$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
> "John G" <Greentest@ozemail.com.au> writes:
>
> There's no problem in the UK, as our mains supplies are polarised
> and live/neutral distinction maintained into appliances.
> Most other parts of Europe do not have polarised socket outlets though.
>
> --
> Andrew Gabriel

Thanks Andrew for the coments.
I will be moving to Portugal, possibly later to Spain.
I'll watch for that possible polarization problem

rf

RedFox

2005-08-15, 4:21 pm

"Palindr?me" <sb382638@hotmail.com.invalid> wrote in message
news:11g0nl21bg6s6b6@corp.supernews.com...
> RedFox wrote:
how[color=darkred]
look[color=darkred]
the[color=darkred]
problem[color=darkred]
an[color=darkred]
I[color=darkred]
small[color=darkred]
>
> Well, domestic VCRs are effectively obsolete now anyway and new ones are
> very cheap. But I would transfer the tapes to DVDs and move on.

That's exactly my plan but I don't have the time before I move.

> For AVR, read autotransformer. OK, you can get autotransformers with
> switched taps that act as an "Automatic Voltage Regulator" - to allow
> for very variable utilitiy supplies. You probably won't need anything
> that complicated or expensive and a simple 220 > 110 volt
> autotransformer will do. Maplin (UK) have one rated at 100W:
>
> http://www.maplin.co.uk/Module.aspx...=31899&doy=15m8
>
> Note that these do NOT change the frequency - but only the voltage. So
> typically it will change 220-50Hz => 110 - 50Hz
>
> If the Sony receiver is also a mains-driven alarm clock - you will have
> problems. It quite possibly won't keep accurate time. There is often a
> link on the clock board inside that can be made or broken to allow for
> mains frequency (much like the mechanical equivalent of a sleeve on a
> shaft or a pulley change, as I suggested for mechanical kit) so it may
> be possible to fix this - but the link is probably soldered and you need
> someone used to working with asoldering iron on electronics, if you
> aren't.
>
> --
> HTH
> Sue

Thank you. Thank you. Thank you :-)

The Sony doesn't have an alarm clock but it may have a timer.
It's been a while since I had a close look.

I'll make a note of your comment and will investigate it. I
have used soldering irons mannnnnnnnnnny times.

rf

RedFox

2005-08-15, 4:21 pm

John G

2005-08-15, 9:21 pm

"Palindr?me" <sb382638@hotmail.com.invalid> wrote in message
news:11g13dehn70vde7@corp.supernews.com...
> John G wrote:
>
>
> "Most"? I hadn't realised that, would you like to list a few?
>
> They are certainly widely available in the UK. If you would like to go
> to rswww.com and search on "autotransformers" - you would find
> everything from a few tens of watts single phase to rather larger
> three phase.
>
> The ones intended for "consumer" use have a permanent mains lead with
> a moulded on plug - the UK plug is polarised and the problem that you
> mention cannot happen unless the wiring infrastructure is incorrect.
>
> --
>
> Sue

Yes I thought afterwards I should have said SOME rather than most.

But it is still possible to buy 13amp plugs in the UK and misswire
anything. (RS pt no. 490-009 for instance)

AND some autotransformers listed by RS are commercial (rather than
consumer) with terminals to be miss wired with ease.

So my caution remains even if it is not recognised as a problem in some
countries.
--
John G

Wot's Your Real Problem?

phil-news-nospam@ipal.net

2005-08-15, 11:21 pm

On Mon, 15 Aug 2005 20:05:10 +1000 John G <Greentest@ozemail.com.au> wrote:

| AUTOtransformers are not permitted in most 230volt countries because it
| is possible to get your 110volt device connected to the 230volt hot and
| a tap half way down instead of the neutral and a tap halfway up.

I know at least in Schuko plug countries, and compatible, polarization
is not applied to the plug pins, so either one could be grounded. That's
why an autotransformer is unsafe. The type of plugs used in UK and AU
could be polarized since there is only one way to plug them in. Since
I have heard that Argentina uses the same plug as Australia, but with
the polarization reversed, that would imply there is a standard in these
countries. But of course there is the risk when 110 volt users travel
to these countries.

The plugs in the USA appear to have been polarized (the grounded slot
is larger) for quite a long time. I recently saw a receptacle that was
made in 1920, and it was polarized.

| I would be very surprised if they are allowed in the UK but then I do
| not know where you or the OP are.

Just use a full isolation transformer.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

phil-news-nospam@ipal.net

2005-08-15, 11:21 pm

On 15 Aug 2005 12:59:50 GMT Andrew Gabriel <andrew@cucumber.demon.co.uk> wrote:
| In article <430068d7$0$4552$5a62ac22@per-qv1-newsreader-01.iinet.net.au>,
| "John G" <Greentest@ozemail.com.au> writes:
|>Caution>>>>>>>
|>AUTOtransformers are not permitted in most 230volt countries because it
|>is possible to get your 110volt device connected to the 230volt hot and
|>a tap half way down instead of the neutral and a tap halfway up.
|>I would be very surprised if they are allowed in the UK but then I do
|>not know where you or the OP are.
|
| There's no problem in the UK, as our mains supplies are polarised
| and live/neutral distinction maintained into appliances.
| Most other parts of Europe do not have polarised socket outlets though.

In most cases there should be no need for this. Everything metal that
does not need to conduct power should be grounded. Edison style light
sockets (screw-in base) make it easy to get shocked on the shell. But
as big as they are, one could touch the center contact, too, so they
are bad news in general. When I build my house, I will have NONE of
them around anywhere. I'm still trying to choose what to have in their
place. I have heard they are no longer allowed in Germany. Maybe I
will have to do my light hunting in Europe and figure out how to comply
with the voltage limitations for lights in the NEC (US electrical code).
I may well go with 12 volt lighting all over.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

magic

2005-08-17, 4:21 pm

hei,

Could be Autotransformer (technology moving fast). Whatever power or
voltage or else you need, the input should have nominal percentage
allowed (+ - ). This means too ideal to get actual figure.

tks

magic

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