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Correct abbreviations for electrical units.

broadgage
One thousand watts is it 1Kw or is it 1KW both are used.

Is a "board of trade unit" 1Kwh or is it one 1KWH.


Likewise 1Mw or 1 MW

And 1Mwh or 1MWH.


And spelling.

Power inverter or power invertor or is either correct.
  • 0
    Correctly, there is usually a space separating the value from the units, so:


    1.5 kV

    400 V

    1 MΩ

  • 0
    So should I write Kilocycles or kilocycles Kc/s or kc/s. Yes I know its or herts now but I can't pronounce that but I can pronounce  cycles.
  • 0
    davezawadi (David Stone):

    Simon, we do not usually refer to kK, and the temperature is not kelvins, it is Kelvin, say 300 K. The degrees are Centigrade degrees, just that the zero is moved, for very low temperatures, and certain thermodynamic points which depend on absolute temperature. 0K is about -273 degrees C.


    The National Physical Laboratory would disagree with you on that one, as would the US National Institute of Standards and Technology (NIST).  The unit of temperature is kelvin, and for current is ampere.  And the same for all the derived units (hertz, newton, pascal, joule, watt, and so on).

    https://www.npl.co.uk/si-units
    https://physics.nist.gov/cuu/Units/units.html


    But, oddly, temperature can also be in degrees Celsius, with a capital C.


  • 0
    Simon Barker:
    davezawadi (David Stone):

    Simon, we do not usually refer to kK, and the temperature is not kelvins, it is Kelvin, say 300 K. The degrees are Centigrade degrees, just that the zero is moved, for very low temperatures, and certain thermodynamic points which depend on absolute temperature. 0K is about -273 degrees C.


    The National Physical Laboratory would disagree with you on that one, as would the US National Institute of Standards and Technology (NIST).  The unit of temperature is kelvin, and for current is ampere.  And the same for all the derived units (hertz, newton, pascal, joule, watt, and so on).

    https://www.npl.co.uk/si-units
    https://physics.nist.gov/cuu/Units/units.html


    But, oddly, temperature can also be in degrees Celsius, with a capital C.




    So even the supposedly learned, pointed headed, white coated people can get things wrong.


    Z.


  • 0
    Even my 1929 book entitled "Mechanical World Electrical Pocket Book" advertising Brook motors on the front cover, uses a small v for Volts. GGGGRRRRRRRRRrrrrrrrrrrrrrrrrrrrrrrrrrrrrr.


    That is no way to show respect for poor old Alessandro.


    So, we use a big V when it has a number in front of it like 400 V, but a small v when referring to an unspecified number like "low voltage".


    Z.
  • 0
    But they are inconsistent! The thermodynamic temperature is Kelvin (K) but the Celsius temperature is degrees Celsius? If you think that is right you will believe anything! I think that I defined it in the proper scientific manner. You need to give the reason you think this inconsistency is correct because I was taught exactly as I said by a relatively important Electrical Engineer. Looking at a few of the Physics textbooks I have, the problem seems to have occurred when °C was changed to Celsius. The textbooks are happy that the symbol K and word Kelvin temperature measured using the centigrade scale from absolute zero. The same does not happen with Celsius, which is a temperature measured from the ice point in centigrade degrees. Very odd, however, the error is repeated throughout many GCSE and A level textbooks, but most of my University level ones ignore the subject completely. As most can understand what is meant by either designation of temperature it probably doesn't matter too much.


    You will notice that all this is somewhat similar to BS7671, a committee comes to some definition by agreement, and after discussion, a vote may be taken. It is usually quite difficult to overturn a majority, so the consensus, right or wrong, tends to end up in the resulting document, book, or whatever! The arguments can go on for a long time, several of the committee having strong views, but the Chairman has to get a result, hence the vote. It happens a lot.
  • 0
    Simon Barker:

    The National Physical Laboratory would disagree with you on that one, as would the US National Institute of Standards and Technology (NIST).  The unit of temperature is kelvin, and for current is ampere.  And the same for all the derived units (hertz, newton, pascal, joule, watt, and so on).

    https://www.npl.co.uk/si-units
    https://physics.nist.gov/cuu/Units/units.html



    Strange that the base unit for mass is the kilogram and not gram!


  • 0
    There's probably a good reason why BS 7671 changed the abbreviation for "alternating current" from "a.c." to "AC" too - but the logic escapes me.

       - Andy.
  • 0
    Why do we speak of AC Voltages instead of just AV (Alternating Voltages) ?
  • 0
    ebee:

    Why do we speak of AC Voltages instead of just AV (Alternating Voltages) ?


    ebee, now I know how you got your nickname. Please don't ask any more awkward questions. ??


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