220 volts Versus 120 volts

Discussion in 'General Electronics Chat' started by donskiter, Nov 23, 2006.

  1. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
    1. Hi guys! i noticed that every countries have their different voltages supply..in my country we used 220volts other countries used 120volts... im just confused can u pls enlighten me...what is more economical to used 120v or 220v? advantages & disadvantages using 120V or 220V? We all know a TV that was manufactured at Japan having 120v can used to other country that have 220V using step up transformer...

    2. I saw lately my friend have a halogen bulb w/ the specifications of 24Volts ac 5Owatts, the problem is he told me that the store he used to buy that bulb are out stock only available are 22.8Volts ac 50 watts...This will be used at the OR lights ( heraeusHanaulux ) ...im just confused! that the reason i come out w/ my question no. 1..What is the reason of having different voltages used to light up a bulb having a 50 watts:Is there any effect in intensity of the lights and operation of the equipments? confuse: .....By the way in our countries we used 220volts ac.

    3. 220volts versus 120volts .........:rolleyes:
     
  2. mrmeval

    Distinguished Member

    Jun 30, 2006
    833
    2
    There are three I can think of:

    1)Manufacturing considerations.
    2)Proprietary considerations.
    3)Historical considerations.

    1)For some reason it's easier or cheaper to make it that way or we want to create condition number 3 using condition number 2 so we can retire to the Bahamas.

    2) We want to make it unique to our company so we can create condition number 3.

    3) We made it this way and now you're stuck with it and have to buy goof ball idiotic device. We either did it because it was easier to do then or because we wanted to use condition number 2 to create this condition so that we'd be sipping fruity froo froo drinks and lusting after teenagers in the Bahamas while you're pulling your hair out and lining our retirement fund. Isn't that special?
     
  3. Dcrunkilton

    E-book Co-ordinator

    Jul 31, 2004
    416
    11
    Lower voltages are safer, less of an electric shock hazard. Higher voltages are more efficient in delivering high levels of power (kilowatts) due to the smaller size of wire required. The longer the distance that the power must be delivered, the higher the voltage need to be to minimize losses. (I squared R).
     
  4. wireaddict

    Senior Member

    Nov 1, 2006
    133
    0
    First, as far as the 22.8V lamp is concerned, go ahead & use it on 24V [provided the base is the same so it fits].

    Second, as dcrunkilton said, higher voltage does the same amount of work with less current, therefore less voltage drop across the the feeder wiring. That's why dual voltage motors should be connected for the higher voltage as much as possible. Hope this helps.

    Dave
     
  5. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
     
  6. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0

    Im a bit confused? u told me that..( Higher voltages are more efficient in delivering high levels of power (kilowatts) due to the smaller size of wire required )...In our country we have 220 v supply...I have aircon in my room i noticed that when the technician install it he used other wire that is more bigger in size compare to other wiring in my house..i know that aircon have higher wattage...Can i have also mathematical explanation regarding to my question ( power, current,volts..)...ADVANCED THANKS :) ...
     
  7. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
    THANKs....Ya... the base appearance are identical ....But the problem is we know that there difference is very small but it might short it the life span of the bulb & it might burn sooner...what do u think? Actually We still searching & waiting for the Bulb....hope to rcve reply to u as soon as possible...thaks
     
  8. wireaddict

    Senior Member

    Nov 1, 2006
    133
    0
    Yes, the bulb will burn out a little faster, maybe a few days sooner out of a typical life span of maybe two years. Not a big deal. 24 volt lamps are able to withstand the 28 V [battery] charging voltage in military vehicles. If you're really interested in long lamp life consider using 24 V white LEDs; they're directly interchangeable with most incandescents. You can find them online via Google; one source is NTE [www.nteinc.com].
     
  9. donskiter

    Thread Starter Member

    Nov 17, 2006
    29
    0
    Finally we found the bulb w/ 24 volt in other store in our place.... Bye the way Thanks for the idea & advise wireaddict...
     
  10. Dcrunkilton

    E-book Co-ordinator

    Jul 31, 2004
    416
    11
    This link will give you more details :
    http://www.allaboutcircuits.com/vol_2/chpt_10/1.html

    An over simplified version follows:

    If a 2000 W load is fed by a 100 V source the current required is:
    P=EI
    I=P/E = 2000/100 = 20 A


    If the 2000 W load is reconfigured for a 200 V source, the current is cut in half:

    I=P/E=2000/200 = 10A

    Therefore a smaller cross-section wire can be used which saves on the weight of copper and cost. The way to decrease the current for the same amount of power is to increase the voltage.

    The higher the wattage of the load and the longer the distance to the load the more important it is to minimize the wire size by going to a higher voltage. For example, the power line between your line transformer and the utility subatation is 7,200 V. The line between the substation and generating station could be 10's to 100's of thousands of volts.
     
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