50 Hz and 60Hz

Discussion in 'General Electronics Chat' started by msak671@hotmail.com, Aug 10, 2013.

  1. msak671@hotmail.com

    Thread Starter New Member

    Aug 4, 2013
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    I want to ask what is the difference between 50Hz and 60Hz, because in my country there is voltage 220V, 50HZ but in some countries they are having 110V, 60Hz.
    So I am using a step down transformer which is 220V to 110V converter, so i want to ask that if i use appliances which works on 110V 60Hz then will it work???
    can my transformer convert 50Hz into 60Hz too??
     
  2. MrChips

    Moderator

    Oct 2, 2009
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    No, the transformer cannot change the line frequency.

    How well the conversion works depends on the specific appliance.

    If the unit converts the AC to DC, e.g. most computer electronics, audio, wall warts, etc. it should work ok.

    If the unit provides heat energy such as toaster, electric frying pan, it should be ok.

    If the unit depends on the AC 60Hz that it is designed for, e.g. electric AC motors, wall clocks, then no, it will not work properly.
     
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  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If the portable appliances have Universal motors, (many have) you will find very little difference.
    If split phase induction motors, they will run slightly lower in RPM, and possibly slightly higher amperage.
    As already mentioned, if purely resistive, then no difference.
    Only things that use synchronous motors will be off ( I doubt that you have a record player!;)).
    Max.
     
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  4. hhechmi

    New Member

    Aug 10, 2013
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    It should work fine, most components will tolerate a 1/6 aproximate increase in current, but any AC rotating component, will run 5/6 slower. 50 and 60 hz are the number of time the current alternates (AC) in a second from hight to high. It is generally tied the rotational speed of the generator producing the electricity. In the US and most of the American Continent, a multiple of 60Hz and 110V phase to neutral. In the rest of the world, it is a multiple of 50 and 220V.
     
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  5. #12

    Expert

    Nov 30, 2010
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    I must disagree a bit. A a long time ago, before switching regulators were invented, I did the math that said my analog power supplies would melt if you tried to use them at their alleged limits on 50Hz power. That's why European versions were designed. Do you think that todays computer aided designs include a penny's worth of extra material so they can survive at 50Hz instead of 60Hz? Only if the label says they will.

    Still, the simple loads like heaters will work properly. The carousel in the microwave oven will rotate at 5 RPM instead of 6 RPM, wall clocks will be off by 4 hours a day, stuff like that. Bottom line is, "Read the Label". If you don't find the specification for 50Hz, watch cautiously for overheating until you are sure it is working well.
     
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  6. MaxHeadRoom

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    Jul 18, 2013
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    I have moved back and forth between N.A. and UK (60hz-50hz) and so far have had no problems.
    Most hand tools and appliances use Universal motors, which run from 60Hz down to DC, Hence Universal.
    There are not many synchronous motor clocks around now, most run off of a 32.768Khz crystal.
    Switching supplies in most computer equipment don't care either.
    Induction motors will run that much slower and slightly warmer, but usually within tolerance.
    Max.
     
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  7. #12

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    Thanks, Max. I freely admit that my experience is very old, and I've never left the USA (except to buy a BLT in Canada). I just suffer from what WBahn recently called, "a well nourished sense of paranoia". Those 1973 power supplies I worked on would fail badly on 50Hz, so anything used "off label" rings the caution bell for me.
     
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  8. crutschow

    Expert

    Mar 14, 2008
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    I would think the big concern would be transformers (any device that uses a line powered transformer, a good example being most A/V receivers). They are usually designed very close to their design limits to minimize cost and thus a 60Hz transformer on 50Hz will likely saturate, draw large magnetizing currents, and overheat. Using a 50Hz transformer at 60Hz should generally be no problem.
     
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  9. #12

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    Right. That's the "A" answer. The "B" answer is that the filter capacitors in an analog power supply are usually not oversized by 16% so they can't keep the Vcc high enough between 100Hz rectifier pulses.
     
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  10. ian field

    Distinguished Member

    Oct 27, 2012
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    There are a few things to watch out for; such as a transformer designed for 60Hz (assuming set for the correct voltage) will have lower inductive reactance (Xl) at 50Hz, and will therefore draw more current than intended. If the designer didn't allow enough safety margin - it could let the magic smoke out when you load it!

    Old fashioned mantelpiece clocks & record players with synchronous motors will run at the wrong speed if operated from the wrong frequency.

    Most rectifier input SMPSUs aren't fussy about mains frequency as the bridge rectifier/reservoir capacitor turn it into DC anyway

    Always check the label for voltage though - auto or wide range PSUs are getting more common, but some still have to be set for the right voltage.

    Usually an SMPSU is built for 220V, the reservoir capacitor is split into 2 units in series - a link or switch shorts the junction between the 2 capacitors, to one AC leg of the bridge rectifier to turn it into a voltage doubler - some are automatic, some not - always check!
     
  11. MaxHeadRoom

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    Jul 18, 2013
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    I have used mainly Hammond transformers ,among other major manuf. for many years and all of the specs have always listed a supply of 50/60Hz.
    I just can't see anyone specifically designing such a thing as imprecise as a mains low freq transformer that tight?
    Max.
     
  12. #12

    Expert

    Nov 30, 2010
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    Please review post #5. A 50 Hz transformer requires 6/5 times as much iron to work without magnetic saturation becoming a problem. 20% as a safety factor went out of style when 5% resistors were invented.
     
  13. ian field

    Distinguished Member

    Oct 27, 2012
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    Some manufacturers supply transformers with 2 110V primaries that can be series for 220V or parallel for 110V, presumably you need to give them a little extra safety margin when chosing a VA rating for 220V 50Hz use.
     
  14. #12

    Expert

    Nov 30, 2010
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    Exactly.
    The problem is that this safety margin of 20% more iron is not designed into "60Hz only" transformers. Another aspect is the power line voltage. At my house, it has climbed from 230 RMS to 250 RMS in 40 years, but I still find transformers labeled, "115V/208V/230V" on the shelves at my wholesaler distributor. Try one of those on 250V @ 50Hz and the safety margin that the manufacturer threw in for free would have to be more like 30% to make it work properly.

    ps, must mention that Hammond transformers are top quality, judging from the ones I have used. A 60Hz model rated at 230 volts still won't run for very long on 50Hz at 250 volts, but at least Hammond makes transformers that can work at 50Hz, and some of them have primary taps for high line voltage.
     
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