Electrical Engineering - 50hz appliance on a 60hz power supply

Author

50hz appliance on a 60hz power supply

wilson

2007-09-16, 3:25 am

Can i use a 220volt- 50hz clock radio on a 220volts- 60hz power supply
output??? What will happen if i try to use it on the said power
supply??? Will the digital clock run faster??? PLEASE HELP!!! Thank
you.

contrex

2007-09-16, 9:25 am

On 16 Sep, 06:49, wilson <wilsonchu...@gmail.com> wrote:
> Can i use a 220volt- 50hz clock radio on a 220volts- 60hz power supply
> output??? What will happen if i try to use it on the said power
> supply??? Will the digital clock run faster??? PLEASE HELP!!! Thank
> you.

it depends what kind of clock it is. Many older models were synched to
the AC frequency so that, as you surmise, they will run 20% faster on
60Hz than on 50 Hz. That's one-fifth, or twelve minutes every hour. I
have a suggestion for you. It assumes you have a fairly accurate watch
or other timepiece to use as a reference. The system clock in a PC is
fairly accurate.

1. Plug the clock radio into the AC supply.
2. Set the clock in the clock radio to the right time.
3. Write that time on a piece of paper, or commit it to memory.
4. Wait one hour by your other timepiece. During this time you could
drink some beer, read a book, surf for porn, daydream, whatever.
5. When your reference clock tells you one hour has passed, look at
your clock radio.
6. If the time shown is the same as the watch, the clock radio doesn't
use the AC frequency.
7. If it shows a time 12 minutes later than the watch, it does.
8. That's it.

If it is faster, you can probably still use the radio (people's
voices, music, etc, won't be shifted upwards in frequency by 20%) but
to get any use out of the clock you would have to (a) remember when it
was last showing the right time, and (b) do some mental arithmetic
when you check the time or set the alarm.

Beachcomber

2007-09-16, 5:25 pm

On Sun, 16 Sep 2007 08:35:27 -0000, contrex <mike.j.harvey@gmail.com>
wrote:

>On 16 Sep, 06:49, wilson <wilsonchu...@gmail.com> wrote:
>
>it depends what kind of clock it is. Many older models were synched to
>the AC frequency so that, as you surmise, they will run 20% faster on
>60Hz than on 50 Hz. That's one-fifth, or twelve minutes every hour. I
>have a suggestion for you. It assumes you have a fairly accurate watch
>or other timepiece to use as a reference. The system clock in a PC is
>fairly accurate.
>
>1. Plug the clock radio into the AC supply.
>2. Set the clock in the clock radio to the right time.
>3. Write that time on a piece of paper, or commit it to memory.
>4. Wait one hour by your other timepiece. During this time you could
>drink some beer, read a book, surf for porn, daydream, whatever.
>5. When your reference clock tells you one hour has passed, look at
>your clock radio.
>6. If the time shown is the same as the watch, the clock radio doesn't
>use the AC frequency.
>7. If it shows a time 12 minutes later than the watch, it does.
>8. That's it.
>
>If it is faster, you can probably still use the radio (people's
>voices, music, etc, won't be shifted upwards in frequency by 20%) but
>to get any use out of the clock you would have to (a) remember when it
>was last showing the right time, and (b) do some mental arithmetic
>when you check the time or set the alarm.
>
>

Just to add to this...

Analog clocks (those with motors in them) will most likely not run
correctly at a different frequency.

Digital Clocks - You might find that most will work. These are the
ones that have an internal (quartz or other) timebase.

When digital clocks first came out, in many cases, the timebase was
tied to the power line frequency (not an internal quartz crystal).
The power company was in control of the accuracy of your clock. You
might have a problem with this style clock if you try a different
frequency.

Most modern clocks have a small DC power supply to convert line
voltage (AC) to (DC) and everything runs off of that with an internal
time base. It's a bit cheaper and simpler to build them that way.

Beachcomber

daestrom

2007-09-17, 5:25 pm

"Beachcomber" <invalid@notreal.none> wrote in message
news:46ed942d.19008312@news.verizon.net...
> On Sun, 16 Sep 2007 08:35:27 -0000, contrex <mike.j.harvey@gmail.com>
> wrote:
>
>
> Just to add to this...
>
> Analog clocks (those with motors in them) will most likely not run
> correctly at a different frequency.
>
> Digital Clocks - You might find that most will work. These are the
> ones that have an internal (quartz or other) timebase.
>
> When digital clocks first came out, in many cases, the timebase was
> tied to the power line frequency (not an internal quartz crystal).
> The power company was in control of the accuracy of your clock. You
> might have a problem with this style clock if you try a different
> frequency.
>
> Most modern clocks have a small DC power supply to convert line
> voltage (AC) to (DC) and everything runs off of that with an internal
> time base. It's a bit cheaper and simpler to build them that way.
>

Interestingly, I have a digital clock that has an internal battery backup
for power failures. When there is AC power available, it keeps near perfect
time and doesn't need setting. If the power goes out for an hour or so, the
display is dark (LED's drain batteries pretty fast). When the power is
restored, it is about five minutes fast for every hour it ran on the
battery.

So apparently it 1) Uses grid frequency for a time base when available 2)
Switches to an internal time base when grid is not available and 3) the
internal time base is slightly 'fast' (so I won't oversleep if there's a
power outage at night by design??)

daestrom

> Beachcomber

Don Kelly

2007-09-18, 3:25 am

----------------------------
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote in message
news:46eefb5c$0$32527$4c368faf@roadrunner.com...
>
> "Beachcomber" <invalid@notreal.none> wrote in message
> news:46ed942d.19008312@news.verizon.net...
>
> Interestingly, I have a digital clock that has an internal battery backup
> for power failures. When there is AC power available, it keeps near
> perfect time and doesn't need setting. If the power goes out for an hour
> or so, the display is dark (LED's drain batteries pretty fast). When the
> power is restored, it is about five minutes fast for every hour it ran on
> the battery.
>
> So apparently it 1) Uses grid frequency for a time base when available 2)
> Switches to an internal time base when grid is not available and 3) the
> internal time base is slightly 'fast' (so I won't oversleep if there's a
> power outage at night by design??)
>
> daestrom
>

Mine runs a bit slower on battery backup but I am retired. Does it have an
employment sensor or simply assume that if you have the alarm on- you have
to work?
Cheers
--

Don Kelly dhky@shawcross.ca
remove the X to answer

contrex

2007-09-22, 1:25 pm

On 16 Sep, 21:45, inva...@notreal.none (Beachcomber) wrote:

> When digital clocks first came out, in many cases, the timebase was
> tied to the power line frequency (not an internal quartz crystal).
> The power company was in control of the accuracy of your clock. You
> might have a problem with this style clock if you try a different
> frequency.

My father was a power station engineer before he retired, and he told
me how every hour or so they used to compare the time shown by a clock
synched to the local AC with that shown by an accurate quartz clock,
and if there was any discrepancy, speed up or slow down the
alternators until agreement was reached.

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