Re: How Does an Electric Motor Know How Much Electricity Is Needed

From	Sylvia Else <sylvia@not.at.this.address>
Newsgroups	sci.physics
Subject	Re: How Does an Electric Motor Know How Much Electricity Is Needed
Date	2016-04-27 15:41 +1000
Message-ID	<dob1noFrlo9U1@mid.individual.net> (permalink)
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On 27/04/2016 3:25 PM, benj wrote:
> On 04/26/2016 11:49 PM, Sylvia Else wrote:
>> On 27/04/2016 1:32 PM, Wally W. wrote:
>>> On Wed, 27 Apr 2016 13:14:03 +1000, Sylvia Else wrote:
>>>
>>>> On 27/04/2016 12:58 PM, Wally W. wrote:
>>>>> On Wed, 27 Apr 2016 11:33:17 +1000, Sylvia Else wrote:
>>>>>
>>>>>> On 25/04/2016 2:39 AM, reber g=emc^2 wrote:
>>>>>>> It even pulls in more electrons when doing moire work
>>>>>>> automatically.WOW  I can see why the thickness of a wire obeys the
>>>>>>> inverse square law.  I love electric motors,and I'm big on electron
>>>>>>> flow. Trebert
>>>>>>>
>>>>>>
>>>>>> With increasing load, it slows down. As it does, the current has to
>>>>>> increase so that the back EMF at the reduced speed still equals the
>>>>>> applied voltage.
>>>>>
>>>>> It's all describable, but it is still akin to magic.
>>>>
>>>> It doesn't seem akin to magic to me.
>>>>
>>>> Sylvia.
>>>
>>> Lessee ... the generator in the next town knows just how many
>>> electrons it should send to my motor.
>>
>> Of course it doesn't. The electrons in the wire respond to the local
>> voltage gradient in the wire. Increasing the load on your motor slows it
>> down, and the reduced back EMF increases the voltage gradient at the
>> input to the motor. So more electrons at that point. That changes the
>> voltage gradient a bit upstream, and more electrons flow there. The
>> change propagates along the wire, at a good fraction of the speed of
>> light, until it eventually reaches the generator, which responds
>> accordingly.
>>
>> With an AC system, everything's cycling 50 or 60 times a second anyway,
>> and the effect of the motor load is superimposed on that.
>>
>> Sylvia.
>
> Nice theory Sylvia, but generally speaking motors don't slow down when
> delivering power. So how does your theory work with synchronous motors?

In a synchronous motor, the current and the power factor, are a function 
of the angle between the rotor and the rotating field. When you load a 
synchronous motor there is indeed a temporary reduction in speed while 
the angle increases, which leads to an increase in current and power 
factor. The increased current, coupled with the angle, cause in increase 
in torque, which prevents further increase in the angle, and the speed 
returns to what it was originally.

Again, nothing magical, just a straight forward application of 
electromagnetism.

Sylvia.

Thread

How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-24 09:39 -0700
  How Does an Electric Motor Know How Much Electricity Is Needed HVAC <mr.hvac@gmail.com> - 2016-04-24 09:56 -0700
    Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-24 23:52 -0400
      Re: How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-25 11:49 -0700
        Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-25 14:37 -0500
          Re: How Does an Electric Motor Know How Much Electricity Is Needed Sergio <invalid@invalid.com> - 2016-04-25 21:14 -0500
  Re: How Does an Electric Motor Know How Much Electricity Is Needed Sergio <invalid@invalid.com> - 2016-04-24 12:17 -0500
  Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-24 14:14 -0500
  Re: How Does an Electric Motor Know How Much Electricity Is Needed Double-A <double-a3@hush.com> - 2016-04-24 13:41 -0700
    Re: How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-24 16:19 -0700
      Re: How Does an Electric Motor Know How Much Electricity Is Needed HVAC <mr.hvac@gmail.com> - 2016-04-24 16:45 -0700
      Re: How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-25 11:45 -0700
        Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-25 14:25 -0500
          Re: How Does an Electric Motor Know How Much Electricity Is Needed jimp@specsol.spam.sux.com - 2016-04-25 19:39 +0000
          Re: How Does an Electric Motor Know How Much Electricity Is Needed Double-A <double-a3@hush.com> - 2016-04-25 17:08 -0700
            Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-25 19:16 -0500
              Re: How Does an Electric Motor Know How Much Electricity Is Needed jimp@specsol.spam.sux.com - 2016-04-26 00:41 +0000
              Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-25 23:05 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-26 03:11 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Sergio <invalid@invalid.com> - 2016-04-26 17:29 -0500
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Double-A <double-a3@hush.com> - 2016-04-26 13:11 -0700
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-26 19:03 -0500
          Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-25 21:59 -0400
  Re: How Does an Electric Motor Know How Much Electricity Is Needed Sylvia Else <sylvia@not.at.this.address> - 2016-04-27 11:33 +1000
    Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-26 22:58 -0400
      Re: How Does an Electric Motor Know How Much Electricity Is Needed Sylvia Else <sylvia@not.at.this.address> - 2016-04-27 13:14 +1000
        Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-26 23:32 -0400
          Re: How Does an Electric Motor Know How Much Electricity Is Needed Sylvia Else <sylvia@not.at.this.address> - 2016-04-27 13:49 +1000
            Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-26 23:53 -0400
              Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-27 00:06 -0400
            Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-27 01:25 -0400
              Re: How Does an Electric Motor Know How Much Electricity Is Needed Sylvia Else <sylvia@not.at.this.address> - 2016-04-27 15:41 +1000
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-27 07:06 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed edprochak@gmail.com - 2016-04-27 05:31 -0700
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-27 09:21 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed edprochak@gmail.com - 2016-04-27 11:06 -0700
                Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-27 11:22 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed jimp@specsol.spam.sux.com - 2016-04-27 16:44 +0000
                Re: How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-27 11:35 -0700
                Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-27 18:44 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed Wally W. <ww84wa@aim.com> - 2016-04-27 22:16 -0400
                Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-27 23:09 -0400
      Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-26 23:34 -0400
  Re: How Does an Electric Motor Know How Much Electricity Is Needed "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-04-27 11:44 -0700
    Re: How Does an Electric Motor Know How Much Electricity Is Needed Sam Wormley <swormley1@gmail.com> - 2016-04-27 15:45 -0500
      Re: How Does an Electric Motor Know How Much Electricity Is Needed Sergio <invalid@invalid.com> - 2016-04-27 22:30 -0500
        Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-28 00:38 -0400
    Re: How Does an Electric Motor Know How Much Electricity Is Needed benj <nobodyxx@gmail> - 2016-04-27 18:43 -0400
  Re: How Does an Electric Motor Know How Much Electricity Is Needed gyansorova@gmail.com - 2016-04-27 11:58 -0700

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