Electronics Forum / Basics / April 2007

  Why do you think should we use square waves?

  You couldn't afford to pay your electric bill if it was a square
wave, because the line and transformer losses would be excessive.

Why are you an idiot HABSHI ?

Graham

An AC generator, by virtue of its design, produces sine wave voltage. A
square wave could be produced from a DC source, but the harmonics would
cause extreme losses as well as annoying audible noise. Three phase AC
produces constant power, which means the generator will not present a
variable load to the driving force, and maximizes efficiency.

Higher frequency AC can be more efficient by reducing sizes of
transformers, motors, and other magnetic components, but audible noise
becomes even more annoying, and long distance transmission suffers from
higher losses. Many long distance HV transmission lines are now DC,
converted back and forth from/to AC by means of SCRs, IGBTs, and other
solid state devices.

Paul

On 29 Apr 2007 21:31:44 -0700, in message
<1177907504.620230.30140@c35g2000hsg.googlegroups.com>, Shashi
<shashidharaar@gmail.com> scribed:

Because it's the cheapest and easiest way to transmit power, and the second
most efficient means.

What would you use to produce the square wave?  What would its advantages
be for power transmission?  What would be the disadvantages?

"Shashi"

**  Cos that is what rotating generators / alternators have produced since
decades.

** Cos the ratio of RMS to peak value being  0.71 has become so important.

Square wave power that would operate lamps normally would not operate 90%
of electronics.

........   Phil

Transformers and motors would be inefficient and very noisy. Light
bulbs would be noisy, too. Power distribution systems would have
terrible spike and ringing problems, and capacitor or rotating
power-factor correction wouldn't work. The square waves would be
hopelessly distorted by the time they got to a load.

Is that enough?

Long-distance high-voltage transmission lines are sometimes DC.

John

Because sine is defined exactly in time and does NOT introduce harmonics
which can have unpredictable influences on different products.
BTW, what IS 'square wave AC?'
This kind of 'math' keeps the "penny counters" happy and the industry
prosperous.

HTH

Stanislaw.

Sine is easier to generate, higher harmonics
cause power loss, and unwanted noise.