USA mains voltage.

[PeterD]

That confuses voltage and frequency in the question and reply. For
frequency, a transformer designed for 50 hz will usually work just fine
at 60, but one designed for 60 may not work well at all on 50 hz power.

Ignoring issues such as ferro-resonate transformers and other frequency
optimized transformers.

 

[Phil Allison]

"Peter Dope"

Yep, Japan's standard is 100 volts--the only country that I know of with
that voltage! How'd that happen? Got me!

** The end result of very long cable runs from overloaded US supplied 110
volt diesel generators back in 1945. The average voltage at outlets was
around 90 to 100 volts - so lamps and other locally made appliances were
sized for this.

Most of Japan's pre WW2 electricity system was destroyed by USAAF bombing.




.... Phil

 

[Martin Brown]

You have it backwards. It is crappy US only transformers in cheapo
wallwarts that saturate on Japanese 50Hz mains and they don't exactly
blow up so much as run mad hot, then melt the casing, blow fuses and/or
catch fire. Decent cheap generic global PSUs are widely available to US
ex-pats in Akihabara and similar electronics markets in Japan.

Many unregulated supplies have enough headroom that the 20% lower
voltage isn't an issue unless under heavy load, but the lower frequency
in the 50Hz part of Japan can be bad for US 60Hz only transformers. It
is much less of a problem these days with modern switchers.

Domestic Japanese kit is always good for 50 or 60Hz - it has to be. Most
will tolerate a 20% overvoltage on the mains input without too much
complaint, but obviously will run hotter as a result.

Regards,
Martin Brown

 

[Phil Allison]

"Martin Brown = Fool "

You have it backwards.

** No - you have.

It is crappy US only transformers in cheapo wallwarts that saturate on
Japanese 50Hz mains

** Impossible - since the AC voltage is only 100 volts

and they don't exactly blow up so much as run mad hot, then melt the
casing, blow fuses and/or catch fire.

** All total, ABSOLUTE BULLSHIT !!!


.... Phil

 

[Jamie]

I always thought that the 120 VAC spec was for the service entrance,
and 115 VAC at the receptacle.
I frankly don't know where the 117 or 100 numbers comes from.

Anyway got the real scoop on this?
I may have learned it at one time, but have since forgotten it.

-mpm

Yes, you're correct..

120 at the pole, 115 at the plug with a load on it.

5% drop on the average is what's allowed in voltage drop
from the service to your outlets with a load.
Lowest Voltages(loaded heavy) : 110, 220 and 440
Loaded voltages(average) : 115v, 230, and 460.
highest(unloaded): 120, 240 and 480..

It's not uncommon to see the high voltages exceed their limits, for
example, we may see 125, 245 and 496 volts here..

Of course you also have 208 which there really isn't a window
spec that I know of, unless you count the 5%. Most of the time that I
know of, this is used for lighting and
a tap is used (Delta) to get your 120 service. I have seen 220 equipment
operating off of 208 voltages and seem to be ok as long as you don't
push them to the limits, motors for example.


Jamie