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I'm curious as to how household appliances are able to convert frequency, obviously they can change voltage through transformers. If anyone could just tell me what devices change frequency and I can do some research myself, just having trouble getting started on the topic! I'm no engineer, just an electrical apprentice who is curious, none of my tradesman have looked into it before. Thanks!

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  • \$\begingroup\$ There is no simple way to change frequency of AC voltage. If it has to be done, the AC must be changed to DC (rectified and filtered) and then changed back to AC at the new frequency. \$\endgroup\$
    – DoxyLover
    Commented May 2, 2014 at 2:00
  • \$\begingroup\$ Okay, thank you :) i think i misunderstood a few things i was told, and it lead me to think that 'universal' appliances converted the mains frequencies they recieved, as oppose to thinking of it as the frequencies they recieve are less relevant. \$\endgroup\$ Commented May 2, 2014 at 3:42

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AC frequency conversion is not done in any household appliances that I know of, barring audio/music peripherals that only deal with small-signal voltage and current levels. Appliances rated for both 50 and 60 Hz either involves transformers with multiple taps that balance between the different RMS power of the two frequencies, or implement switching power supplies.

If you're looking for equipment that can produce AC power at different frequencies, you'll want to look into what's called a 'variable-frequency drive.' I believe they're used as variable-speed motor drivers, such as for centrifuges and other lab equipment.

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Appliances are not designed to be universally compatible. Although most stove/ovens convert AC to DC for the smart control panel with a crystal controlled clock, so V-I ratings are relevant only. But for large motorized AC appliances, these are not cost effective to be designed for dual frequencies 50/60 with some exceptions.

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  • \$\begingroup\$ Okay, so what would happen in the case of using an American appliance in Australia and vise versa? @user41215 I asked a question yesterday, and was told that most appliances are universal, if I remember correctly, I'll have a read of what I was told yesterday just to make sure, but I believe someone mentioned most appliances are universal, and take mains power, and convert the voltage and frequency \$\endgroup\$ Commented May 2, 2014 at 2:27
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    \$\begingroup\$ Major appliances tend to be cost reduced for regional power sources only \$\endgroup\$
    – user41215
    Commented May 2, 2014 at 2:34
  • \$\begingroup\$ Ah okay, I had another look at the answers I received yesterday and it's a bit different to what I thought, I'll take some time to look over what you've said and what I was told yesterday, thanks for your help! \$\endgroup\$ Commented May 2, 2014 at 2:37
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    \$\begingroup\$ Many electronic devices have "universal" power supplies - they will operate correctly on 90 to 250 volts (or so) and 50 or 60 Hz power, to produce the DC voltages required by the device. Heating appliances are generally designed for one voltage (120 or 240 volts) and don't care about frequency. Things with electric motors driven directly by the AC power input likely won't work correctly on the wrong frequency (60 Hz motors will run slower, and may overheat, on 50 Hz.) \$\endgroup\$ Commented May 2, 2014 at 2:54
  • \$\begingroup\$ What about a resistive AC load like a light bulb? I could imagine that theoretically if you ran a light bulb on 1 Hz you could see it light up twice per second. Are you able to give me any examples of appliances that will operate correctly with different voltages/frequencies? I'm wondering if there would be minor changes in the operation of the appliances with the small fluctuations of frequency like 50-60Hz, like non critical, small changes in the operation of the appliance? surely it must have some effect on the devices. @PeterBennett \$\endgroup\$ Commented May 2, 2014 at 3:38

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