On Friday, 19 July 2019 18:49:20 UTC+1, NY wrote:
"The Natural Philosopher" wrote in message
...
On 19/07/2019 16:30, NY wrote:
"Martin Brown" wrote in message
...
A decent proportion of hotel bathrooms have 240v ac available in them.

Quite possibly, though maybe 220 V (two anti-phase 110 V supplies, as is
supplied to houses to run high-power devices like aircon, tumble driers,
cookers).

However I'd still expect it to be 60 Hz, not 50 Hz. Depending on how much
the transformers or coils in motors are tuned, they may or may not work
at 60 if there are designed for 50.


60hz works on 50hz transformers. The reverse is less lilkely to be true

Ah, OK. I thought it might be a reciprocal arrangement, but evidently it's
not.

no, a transformer needs more steel to run at 50Hz than 60.

I wonder how US came to standardise on 60 Hz and Europe on 50 Hz in the
first place.

they had more sense

Is it generally 50 Hz = 230 V (+/- tolerances) and 60 Hz = 110 V (+/-
tolerances)

mostly

or are there some countries which have standardised on 230 V @
60 Hz or 110 V @ 50 Hz?

Japan has 100v at both 50Hz & 60Hz. US supplies 220v at 60Hz as well as 110.

In my innocence, I thought that 240 V implied bayonet light bulb fittings
and 110 V implied Edison screw light bulb fittings... Until I first went
round IKEA and couldn't work out why a Swedish (and so 230 V/50 Hz) country
would stock only screw-fitting light bulbs. Then I learned that we in the UK
are in the minority, and many countries *both 110 V and 230 V* use the same
screw fittings.

110v & 230v ES are different sizes, but so close that you can still get bulbs into the wrong size socket, albeit with resulting problems! The Victorians still have a thing or 2 to answer for.

Incidentally, if you are buying SES (female) to SBC (male) or to LBC (male),
look out for a design flaw that we encountered with some cheap converters
(probably of Chinese origin): the central spring contact which should touch
the tip of the ES bulb, also makes contact with the sleeve of the bulb as it
is pushed in when the bulb is screwed in. Result: a loud bang and the MCB
(and maybe RDC) trips. Happened to us with several converters of one make,
so they are going back to Amazon with a note "DANGEROUS PRODUCT: WITHDRAW
FROM SALE".

Lightbulb adaptors have always not been designed right & very prone to not working. No BS ever standardised them. A percentage are fundamentally unsafe.


NT

Even more incidentally, when you are installing Philips Hue bulbs, or other
similar ones which are capable of being turned off at the bulb even though
there is power to the socket, don't make the mistake that I did as I was
rewiring the GU10 adaptors up in the bedroom ceiling. Remember that even
though none of the bulbs are lit, there may still be power. I'd been so good
about turning off both the wall switch and the relevant MCB, apart from the
one time I forgot... 240V through a finger is not to be recommended, even
for the regulation 30 msec before the RCD trips.