Talk:Basic Electrical Generation and Distribution

Merge with electric motors and generators

It has been proposed that this page be merged with the wikibook Electric Motors and Generators due to inactivity on that page. I have decided to try and jumpstart some editing there and have therefore decided to remove this at the suggestion of another user on that page. There will no doubt be some discussion of electrical machines on this page but an in depth treatment would be better kept elsewhere I think.Crobar (talk) 08:50, 16 July 2010 (UTC)

Does this article belong in a physics curriculum?

This article seems to be primarily a discussion of how electrical power is generated and distributed, not about the physics of electricity itself. While informative, I think this article belongs elsewhere.

130.74.33.61 20:21, 11 May 2006 (UTC)Claus Hetzer

I agree. The practice of the generation and distribution of electricity as an application is largely the domain of electrical engineers and should be shelved with other EE topics.

Jtvisona 02:36, 8 March 2007 (UTC)

I studied to be an Electrical Engineer and the discussion in this article, in my opinion, does not belong under electrical engineering. It has to do with Electricity and power generation,so there should be somewhere it could go.

viningc 10:15, 20 May 2008 (UTC)

I agree also, the two are inextricably combined. I.E. One converts Electricity to motion, the other converts motion to Electricity.

damage

This module currently claims that the non-sinusoidal outputs of lower-cost square-wave inverters causes noise and damage to a "lot of appliances".

Is that so? Is this "noise" any worse than plugging these appliances directly into my wall socket, which usually has a bunch of higher-frequency noise?

• resistive heating devices such as toasters, light bulbs, electric ovens -- the element would heat up just as well with DC or a square wave as with a perfect sinusoid. (Edison designed his incandescent light bulbs to work from DC power).
• electronic devices such as microwave ovens, personal computers, transistorized audio equipment -- these devices immediately convert the AC to a regulated DC voltage in their power supply; the rectifier would work just as well (perhaps even better) with DC or a square wave as with a perfect sinusoid.
• Triac dimmers (wikipedia:dimmer) can't work with DC, but they should work fine with a square wave.
• motors: 3 phase power is required to give constant torque. Motors that try to use the single phase available at a residential output are going to have little pulses of torque and pulses of heating no matter how perfect the sine wave is.

The Wikipedia: inverter (electrical) article briefly mentions "Some loads need a nearly perfect sine wave voltage supply in order to work properly.", but doesn't ever mention "damage". This module would be a good place to go into detail -- which loads would those be?

What kind of appliance would be "damaged" or even temporarily affected by the "noise" of a square-wave inverter? --DavidCary (talk) 12:59, 11 August 2008 (UTC)

I have had problems with laptops and motors on a triangle wave inverter, I had no idea that square wave inverters exist. This site lists devices which will not work with a modified sine wave much less a (ghasp) square wave http://www.donrowe.com/inverters/inverter_faq.html#modified (From a Nomad Aug 2008)

Thank you, Nomad. I appreciate the link. Alas, the list on that web page has large categories of things, then qualifies them with "some", with no particulars I can track down -- reminding me of the vagueness of urban legends.

Because I design electronic devices, I would like to know specific details of how exactly things fail, so that I can design things that avoid those particular failure modes. I want to see completely new failure modes! ;-).

Wikipedia: LED power sources#Lighting LEDs on mains specifically mentions "Operation on square wave and modified sine wave (MSW) sources, such as many inverters, causes heavily-increased resistor dissipation in CR dropper, and LED ballasts designed for sine wave use tend to burn on non-sine waveforms. ... An inductor and rectifier makes a more suitable ballast for such use, and other options are also possible. Dedicated integrated circuits are available that provide optimal drive for LEDs and maximum overall efficiency."

That seems to imply that "square wave ... inverters" exist. And I finally get some details. The "CR dropper" technique doesn't work with square wave inverters. However, many engineers consider the "CR dropper" technique "dodgy and dangerous".[1]

Since "CR dropper" power supply has a power factor near 0, it is questionable whether they meet EU-mandated power factor laws, such as EN61000-3-2.

Most devices -- as I've listed above -- don't seem to have any problem with square wave inverters, and in fact work more efficiently with a square wave.

Do any products that were designed after EU-mandated power factor laws went into effect still have this problem? --DavidCary (talk) 03:41, 27 August 2009 (UTC)

Currently this book claims that modified-sine or pure-sine inverters have "the current drain on the direct current supply is less choppy" than square-wave inverters.

It seems to me that the current pulled from the battery will be more "choppy" with those inverters than with a square-wave inverter.

Incandescent light bulbs (and high-power-factor computer power supplies) will pull -- except during the very brief zero-current switchover -- constant power from a square-wave inverter, which in turn will pull constant current from its battery. Incandescent light bulbs (and high-power-factor computer power supplies) pull a "sine squared" power from a perfect sine wave inverter, and a "square wave power" from a modified sine wave inverter -- in both cases, the light pulls a varying power, a power that is less than 1/4 the max power for 1/3 of the cycle, and more than 3/4 the maximum power for 1/3 of the cycle. --DavidCary (talk) 01:09, 28 August 2009 (UTC)

The noise may depend on the type of motor. Vacuum cleaners typically uses AC/DC brush motor. These should work fine on modified sine. However a fan typically uses a single-phase split-capacitor induction motor, and it's possible that these could be noisier on a modified sine. Mikiemike (talk) 02:21, 29 December 2010 (UTC)