220V to 110V voltage converter for U.S. charger : that works !



#2

Hi everybody,

I recently posted a thread when I was looking for a solution to use the charger designed for U.S. voltage of a HP-33C I received a few weeks ago, as I live in France where the voltage supply is 220V, instead of 110V in the U.S.

First of all, I would thank here all the persons who answered my question and helped me.

I finally found, and bought (12,50 Euro shipping included), a 45W 220V-240V AC to 100V-120V AC Plug-In Voltage Converter, and tested it last days : that works fine !

Probably most of the readers will know this solution, but maybe it may help someone who's got the same "problem" one of this days, who knows ?

This will be my modest contribution to this forum...

Regards.


#3

They are not the same.

A transformer has an iron core (you can tell by its weight), and will deliver a sinusoidal voltage output. In your example, you will get a 110 V sinusoidal output from a 220 V sinusoidal input.

So the output will be similar enough to the USA 110 V mains, and your HP charger (which, incidentally, contains a transformer itself) will not "be aware of any difference" (see note below).

On the other hand, there are devices called "voltage converters", which are suited for irons, hairdryers, mixers, and other appliances. They work by altering the waveform, their output is no longer sinusoidal, but its power is equivalent (root mean square) to the 110 V mains. It is up to the receiving device to cope with the waveform issue. A heating element, a lamp, or a motor will almost always work with such converters; but electronic devices or transformers may suffer because their input will not be similar enough to the 110 V sinusoidal mains.

These voltage converters are electronic circuits, and are much lighter than transformers. Sometimes they are advertised as "travel" or "foreign" power converters.

I would strongly advise against using voltage converters to feed HP calculator AC adapters. They may just work (by luck, or for a while), but they may cause harm, even not instantaneously.

Transformers are on the safe side.

Note: Actually, 220 V mains have a 50 Hz frequency almost everywhere; 110 V USA mains are 60 Hz based. Using the HP USA AC adapter with the 110 V 50 Hz output of a 220 to 110 transformer will make it work a little warmer because of the different frequency and it's influence on the core magnetic behaviour. But this difference will not cause any harm.


#4

Perhaps a minor point, but the single-phase (normal residential or office) voltage here is supposed to be 120V +/-5%, or 114V-126V. The previous requirement was 120V +5% -10%, or 108V-126V, or taking the average of the highest and lowest, 117V, which no doubt explains why that's a fairly common nominal voltage for appliances. That's at the service entrance with no load; the voltage at an outlet on a loaded circuit will be lower, depending on the wiring resistance and load. Often an appliance will have a nominal voltage of 115V or 110V, and many will work okay as low as 100V. Of course for heavier duty appliances that use both "hot" wires, double the voltages.

Regarding the frequency, it's not just the U.S., but all of North and Central America, and quite a bit of South America, that uses 60Hz for most electrical power.

Regards,
James


#5

Hi, James --

Quote:
Of course for heavier duty appliances that use both "hot" wires, double the voltages.

For international readers, this is typical of 120-volt household AC
systems, in which two circuits and a neutral are provided. With the neutral tapped to the center of the 120-V transformer secondary, the two circuits are effectively 180 degrees apart, like a see-saw. Single-phase 240 V for heavy loads -- such as ranges, dryers, and fixed heaters -- is achieved by using both circuits instead of just one circuit and the neutral.

I believe that three-phase 220-V AC is common in Europe, at least in urban areas.

Quote:
Regarding the frequency, it's not just the U.S., but all of North and Central America, and quite a bit of South America, that uses 60Hz for most electrical power.

Surprisingly enough, part of Japan is also developed for 60 Hz, while other parts utilize 50 Hz. The infrastructure built after World War II by American companies, such as General Electric and/or Westinghouse, is 60 Hz. The infrastructure built by European companies (I assume Siemens) is 50 Hz. Energy can be exchanged between the systems using a set of "back-to-back" AC-DC-AC converters.

-- KS


#6

Quote:
I believe that three-phase 220-V AC is common in Europe, at least in urban areas.

Today, it is three phase 230 VAC. Reason was the unification of former 240 VAC (used in Britain) and 220 VAC (used elsewhere). IIRC this was done some 15 years ago.

Best regards, Walter


#7

Hello!

Quote:
IIRC this was done some 15 years ago.

Add 10 years to that ... some things really take awfully long to accomplish! The common 230 volts were agreed upon through IEC standard 60038 in 1983 already.

Greetings, Max

BTW: As others have already said, the small diffrerences in voltage usually create no problems. But the difference in frequency can cause problems, especially with video signals and elecric motors (like in cooling fans and synchronous drives like those of telescope mounts).

Edited: 19 Mar 2007, 7:58 a.m.

#8

Look here for more than you ever wanted to know about power line voltages, frequencies and types of electrical plugs:

http://www.calinst.com/literature.asp

Click on "World Power Guide".

You have to register to do this download but it is well worth it if you want to know about the many variations. Be warned that this is a PDF of over 30 pages.

Scanning the Guide, I found that Johannesburg, South Africa is listed as having both 50 HZ a.c. power as well as d.c. power. My copy of the guide is several years old so I don't know if this is still true.


-- Richard.

#9

Hello Karl,

Quote:
For international readers, this is typical of 120-volt household AC systems, in which two circuits and a neutral are provided. With the neutral tapped to the center of the 120-V transformer secondary, the two circuits are effectively 180 degrees apart, like a see-saw. Single-phase 240 V for heavy loads -- such as ranges, dryers, and fixed heaters -- is achieved by using both circuits instead of just one circuit and the neutral.

In Brazil this system is used only in central São Paulo city, except that the voltages are 110 and 220 V. Everywhere else three-phase wye systems are used (mostly 220/127 V; 380/220 V in some states). Frequency is 60 Hz, as already mentioned by Luiz. Because of São Paulo influence it's not uncommon to hear low-skilled electricians saying 110 V instead of 127 V. Until recently, incandescent light bulbs labeled 110 V (and actually designed for that voltage) were sold all over the country. Of course, they didn't last long under 127 V.

Regards,

Gerson.

#10

Quote:
I believe that three-phase 220-V AC is common in Europe, at least in urban areas.

In the UK (and I assume the rest of Europe) a 3-phase supply is available anywhere at a price. Such supplies are typically used for large motors, or for computer centres. The 'low voltage' 3-phase supply has three wires (red, yellow, blue) at 120 degrees out of phase with one another. The voltage between one phase and earth is 240V, the voltage between two phases is 415V.

I see from Wikipedia the colours are going to be 'harmonised': http://en.wikipedia.org/wiki/Three-phase_electric_power to brown/black/grey.

I don't have any 'big iron' but I understand some hobbyists have a 3-phase supply to their home!


Regards,
John

#11

Hi Andrés, guys;

In Brazil we have the 'conventional' three-phase 220VAC, 60Hz. Reasons appart, I have no informations about where are 60Hz or 50Hz used. I do not remember having access to such information. Anybody?

About video signals and electrical motor speed: current all-analog TV sets (either generation or receivers) are somehow rare, most of the new stuff (if not all) being digital when generating control signals are the issue. TV receivers mainly use switching power supplies, thus converting the AC supply into DC and using high-frequency PWM to control convertion (some thousands of hertz). So the 60Hz reference is internally generated, instead of using the AC mains reference.

Electrical motors designed to operate with 60Hz actually may need extra fanning when connected to 50Hz to keep lower temperature because, in most cases, their fan is built in their own axle and the air flow will be reduced in about 17% in this case.

Cheers.

Luiz (Brazil)


#12

Olá Luiz,

Quote:
Reasons appart, I have no informations about where are 60Hz or 50Hz used. I do not remember having access to such information.

Paraguay uses 50 Hz. Half the turbines in Itaipu are designed for 50 Hz. That's why a 600 kV DC transmission is used when Paraguay sells its surplus energy to Brazil. If I am not wrong, the power of the voltage converters in both ends are 5000 or 6000 MW. That's what I call a voltage converter! :-)

Cheers,

Gerson.


#13

re: "That's why a 600 kV DC transmission is used when Paraguay sells its surplus energy to Brazil. If I am not wrong, the power of the
voltage converters in both ends are 5000 or 6000 MW. That's what I call a voltage converter!"

Even here in the US, where there is no need to change from 50 to 60 Hz, some transmission lines are also run in DC at similar voltage levels, so they get the big voltage converters, too. Benefit: no radiation loss from the line.


#14

I never heard of that before. Interesting.

#15

Hi Luiz, everybody!!

First of all, I apologize if my posting was not as complete or correct as it could have been. My main concern was to alert for possible damage to some of our beloved calculators because of the not-always-known difference between "electronic power converters" and "transformers". I felt time was running out, and something has to be posted in the shortest possible time.

I learned about this difference in a hard way some 30 years ago. I was connecting a (then) rare telephome answering machine (110 V based) in my "soon-to-be parents-in-law" home (220 V, as AC comes here). The salesperson included a power adaptor with the answering machine, but (oh!) it was not heavy at all!... Well, the machine worked for some ten minutes... but then we all heard a loud noise, and the smell of a burned electrolytic capacitor showed that something had went wrong.

I then realized a triac circuit was doing a not good enough "voltage conversion"...

End of story: Fortunately, I was able to put a new electrolytic in, fix the thing, connect a classical transformer, and the whole incident was over; as witnessed by the fact that we are about to celebrate our 24th wedding anniversary this year :-)

Regarding power systems, in Argentina we are supposed to have 220 V 50 Hz, and triphase systems are 380 V. Of course, these are rms, not peak values.

Our government here is trying to "manage" a large increment in the electric power demand, caused by a combined effect of politically-fixed prices, increased economic activity, and little long-term infrastructure planning (you may perceive my disagreement here). So it is very possible that, at this very same moment, we have something like 199.95 V and 48.7 Hz... You know, it is within the 10% range and the populace will not notice it. And the engineers out there have little influence for the upcoming elections. Sad.

One of these days they may decide to "manage" gravity...


#16

I didn't know that Argentina was on the euro-electric standard (220, 50 Hz) rather than the U.S. 60 Hz system. Are your neighbors (other than Paraguay) also 50 Hz?

(O.T. I have a beautiful stringed instrument I had custom-made in Buenos Aires. The 1st try got lost in the mail, but the luthier had insured it and so he simply made another one and sent it along a few weeks later. Apparently valuable things have a habit of getting "lost" in correo argentino. Perhaps there is some "management" of the post as well as electricity and gravity).

Edited: 24 Mar 2007, 9:54 a.m.


#17

It's amazing how well informed and interested this group is in electric power distribution and generation (I assume). I am too and just came across this new book that might be of interest to others here: The Grid. I'm waiting for my copy to arrive so can't tell you how good/bad it is, but there was a review of it in some journal that I get (IEEE Spectrum maybe?) and they liked it.


Edited: 24 Mar 2007, 12:15 p.m.


#18


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