Moving From USA Overseas... Looking For Advice re: Electrical Service and Gear


hello all,

i'm moving from the USA to Vietnam (220V / 50 hz) and am looking for some advice on the best and safest way to hook up my system out there.  the area i'm moving to - district 2 in ho chi minh city - apparently has power outages monthly.  any advice on safely running my gear out there would be appreciated.

  • is it better to have my gear converted to 220V, or simply use a 220V - 120V step down transformer?
  • should i use an uninterruptible power supply (UPS / battery backup) or is a good surge protector sufficient?
  • is it possible to use a step down transformer in line with a UPS, ie, wall to UPS, UPS to transformer, transformer to gear?

as you can see, i have no idea what's the best and safest way to run USA spec equipment in Vietnam and would appreciate all inputs and recommendations.

thanks!
Scott 
128x128srosenberg
+1 Thank you Al.
I’ll wait for your findings as well...

In the meantime I located the website for Todd transformers I mentioned before, the unit is called 3 tap (which I mistakenly wrote prong!) and this co. Has been around for forty years...

anywho, here is a bit from them:
http://www.toddsystems.com/geninfo.html

"No transformer of any type can change frequency. Frequency is unimportant to the normal operation of most loads: most motor driven loads will simply run at a slightly different speed than they did at their rated frequency; simple heating equipment (broilers, coffee pots, etc.) will operate with no problem at all. However, motor loads whose proper operation depends upon frequency, such as clocks, turntables, timers, cassette players, etc. must be converted for voltage with a transformer and then also have their gears and/or pulleys changed for speed correction.

Some motor loads are heat sensitive to frequency changes. To avoid overheating sensitive motors, such as those that continuously stop and start, or run non-stop -- refrigerators, air conditioners, washing machines, shop equipment, etc., it is good practice to run 60 Hz motors at 10% less voltage when operated on 50Hz (e.g. 115 V 60 Hz equipment should operate at 100 - 105 V at 50 Hz). Conversely, to obtain full power from a 50 Hz motor operated on 60 Hz, it is necessary to supply it with 10% extra voltage (e.g. 220 V at 50 Hz should be operated at 250 - 260 V at 60 Hz)."...

lastly, I’ve seen people stating that they’re using external transformers with an amp just like mine (Levinson 532h) overseas with no issues... So I’m thinking that this may be more of an issue with TT, tape decks etc.?...
l'll wait for Al’s inputs...
thanks again

Thanks for the additional info, Lucidear. Following is the text of the inquiry I sent to Acupwr via their website:

Regarding your autotransformers that can convert from 50 to 60 Hz and vice versa, and are indicated as being intended for use with refrigerators, freezers, and other such appliances:

1)Would you recommend that these autotransformers can be used to power a high quality stereo system?

2)Can you provide me with some indication as to how these devices convert frequency? As an electrical engineer I know that a transformer or autoformer by itself cannot do so.

3)Can you provide me with some indication of how greatly the resulting output differs from a pure sine wave. For example is it a stepped approximation of a sine wave, or a sawtooth waveform, or some other approximation of a sine wave having large amounts of distortion?

Thank you.

Shortly afterward I received a phone call from a fellow who described himself as being non-technical but who said he had spoken to one of their technical people. He said that the tech person told him the output is essentially a pure sine wave, but that they would only recommend these devices for use with motor-driven appliances, and would not recommend them for use with a stereo system. I asked why that would be the case if the output is essentially a pure sine wave, and he couldn’t provide an answer but thought it had something to do with the connected motor providing a "kick" of some sort to the transformer. I repeated question 2 to him and again he couldn’t answer. He said he would try to have the tech person contact me to provide further detail, but that hasn’t happened yet.

I’ll post back if and when the tech person provides further info. Meanwhile I can only speculate that the "kick" he refers to, that would be provided by a connected motor, might have something to do with a phenomenon called "inductive kickback." That is the principle by which the induction coil in a car generates the very high voltage pulse that is applied to the spark plugs, and is the reason that a tube amp having an output transformer (which is inductively based) should not be operated without a load.


The bottom line at this point: I would not take the chance of using these devices with valuable audio equipment. Also, as was indicated earlier in the thread there are many audio components that are designed such that they can be used at both frequencies, as long as the voltage is proper. That should be indicated on their nameplate and/or in their manual.

Best regards,

-- Al


No way I'd move such a nice system all that way.  Too risky.  Better to find someone local to take care of your system until you are stateside again.  ;-)
Al,

thanks for you consideration and contributions to this thread.  Acupwr also makes step down transformers that only effect the voltage - frequency remains unchanged.

i have confirmed that all of my gear will be fine on 50hz, so am only condiderig these units.  Do you share the same concerns about the voltage only autotransformers?

is there another step down transformer that you would recommend?

thanks again,
Scott

Al, what do you think will happen if a turntable AC synchronous motor is run on 120 V and 50 hz instead of 60 hz ?
Also, is the the frequency really always stable 60 hz here in the US ? Voltage is definitely not.