Groups > sci.physics.electromag > #20087

Re: Question about power capacity of electrical motors.

From	"Tim Williams" <tiwill@seventransistorlabs.com>
Newsgroups	sci.physics.electromag, sci.electronics.design, sci.physics
Subject	Re: Question about power capacity of electrical motors.
Date	2017-07-23 14:32 -0500
Organization	A noiseless patient Spider
Message-ID	<ol2tdf$1hb$1@dont-email.me> (permalink)
References	<okdk1a$426$1@dont-email.me> <oked4c$dj9$1@dont-email.me> <oksjee$qt5$1@dont-email.me> <oku6ej$6ip$1@dont-email.me> <okvreq$egr$1@dont-email.me>

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"Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> wrote in message 
news:okvreq$egr$1@dont-email.me...
> Thanks for the informative response. So at least one of these high 
> magnetic field labs does it without superconductors. If they do this by 
> being additive of the magnetic fields that raises the possibility it would 
> also work with electric motors.

Yeah, but going over 2T is obviously an economic and thermal challenge.

Room temp superconductors, even if they have to be cooled a bit below room 
temp to be useful, would open up a lot of interesting possibilities, though. 
You could dump the iron, and shrink things quite a bit, even if the Bmax 
isn't any higher.


> BTW, what is the relation between the magnetic field strength, the 
> current, and the power output? That is to say, even if the magnetic field 
> is limited, can we increase the power output by increasing the current 
> nevertheless.

Incomplete: voltage and current, or velocity and torque, is power.

Some motors overlap responsibilities, for example the series wound machine 
has load current in the field winding, so B depends on current, which is 
torque.  But torque depends on B, which is current, so torque actually goes 
quadratically with current.  Similarly, EMF and RPM vary with current, so 
the RPM is highly variable, too.  (Which is the observation: series wound 
and universal motors have very high torque at low RPM, and very high RPM at 
low torque.)

But, broadly speaking, B goes as I, and P goes as B^2.  The force applied to 
the motor is due to a difference in flux densities; flux density gives a 
pressure, the Maxwell strain, p = B^2 / (2*mu).

(Pressure is also energy density, so this gives the energy density of an 
inductor, for instance.)

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Contract Design
Website: http://seventransistorlabs.com

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Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-15 13:43 -0400
  Re: Question about power capacity of electrical motors. Cursitor Doom <curd@notformail.com> - 2017-07-15 18:39 +0000
  Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-15 18:31 +0000
    Re: Question about power capacity of electrical motors. Piglet <erichpwagner@hotmail.com> - 2017-07-15 20:09 +0100
      Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-15 19:19 +0000
        Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 05:44 -0400
          Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 15:24 +0000
            Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 12:17 -0400
              Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 17:07 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:42 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 18:05 +0000
                Re: Question about power capacity of electrical motors. John S <Sophi.2@invalid.org> - 2017-07-21 13:46 -0500
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 15:07 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 19:30 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 17:31 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 22:11 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 19:04 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-22 00:22 +0000
    Re: Question about power capacity of electrical motors. krw@notreal.com - 2017-07-15 18:46 -0400
      Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-16 02:00 +0000
        Re: Question about power capacity of electrical motors. krw@notreal.com - 2017-07-15 22:38 -0400
          Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-16 03:07 +0000
            Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-16 09:20 +0200
    Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-15 21:46 -0400
      Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-16 02:13 +0000
        Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 05:49 -0400
          Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 15:26 +0000
            Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 12:45 -0400
              Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-21 12:08 -0500
              Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 17:10 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:43 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 18:07 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 15:10 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 19:32 +0000
                Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 17:32 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 22:11 +0000
              Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-22 10:51 -0400
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-22 17:55 -0500
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-22 17:58 -0500
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-22 18:56 -0500
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-22 21:25 -0400
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-23 20:01 -0500
                Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-24 05:35 -0400
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-24 08:39 -0500
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-24 20:15 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-25 11:56 +0200
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-25 20:23 -0500
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-26 20:28 -0500
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-29 18:47 -0500
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-29 21:18 -0400
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-29 23:59 -0500
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-31 17:05 -0400
                Re: Question about power capacity of electrical motors. Lofty Goat <rlwatkins@gmail.com> - 2017-07-24 20:13 -0500
    Re: Question about power capacity of electrical motors. David Lesher <wb8foz@panix.com> - 2017-07-17 22:29 +0000
    Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-21 04:18 -0400
      Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 15:29 +0000
  Re: Question about power capacity of electrical motors. John Larkin <jjlarkin@highlandtechnology.com> - 2017-07-15 12:51 -0700
    Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-15 23:47 -0500
      Re: Question about power capacity of electrical motors. benj <nobody@gmail.com> - 2017-07-16 00:58 -0400
        Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-16 09:22 +0200
          Re: Question about power capacity of electrical motors. benj <nobody@gmail.com> - 2017-07-17 01:13 -0400
            Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-17 08:46 -0500
      Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 06:26 -0400
        Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 15:32 +0000
          Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-21 11:09 -0500
            Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-21 21:44 -0400
              Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-21 22:17 -0500
                Re: Question about power capacity of electrical motors. benj <nobody@yahoo.com> - 2017-07-22 02:16 -0400
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-23 10:33 +0200
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-23 16:34 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-24 12:10 +0200
                Re: Question about power capacity of electrical motors. John S <Sophi.2@invalid.org> - 2017-07-24 05:19 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-24 12:32 +0200
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-24 08:52 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-24 16:56 +0200
                Re: Question about power capacity of electrical motors. Serg io <invaalid@invalid.com> - 2017-07-24 12:02 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-24 23:51 +0200
                Re: Question about power capacity of electrical motors. John S <Sophi.2@invalid.org> - 2017-07-24 17:16 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-25 01:12 +0200
                Re: Question about power capacity of electrical motors. John S <Sophi.2@invalid.org> - 2017-07-24 18:25 -0500
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-25 11:54 +0200
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-24 17:19 -0400
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-24 17:10 -0400
                Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-24 23:33 +0200
                Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-24 21:02 -0400
          Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:12 -0400
            Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 17:25 +0000
              Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:45 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-21 18:08 +0000
              Re: Question about power capacity of electrical motors. benj <benj@nobody.net> - 2017-07-21 18:53 -0400
                Re: Question about power capacity of electrical motors. jimp@specsol.spam.sux.com - 2017-07-22 00:23 +0000
    Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 06:00 -0400
      Re: Question about power capacity of electrical motors. Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-07-21 09:48 -0400
        Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:30 -0400
      Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-21 17:30 +0200
        Re: Question about power capacity of electrical motors. rickman <gnuarm@gmail.com> - 2017-07-21 13:34 -0400
          Re: Question about power capacity of electrical motors. John S <Sophi.2@invalid.org> - 2017-07-21 13:08 -0500
  Re: Question about power capacity of electrical motors. "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-07-15 19:51 -0500
    Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-21 06:05 -0400
      Re: Question about power capacity of electrical motors. "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-07-21 19:36 -0500
        Re: Question about power capacity of electrical motors. Jos Bergervoet <jos.bergervoet@xs4all.nl> - 2017-07-22 10:39 +0200
          Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-22 12:47 -0400
            Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-26 18:18 -0400
              Re: Question about power capacity of electrical motors. "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-07-26 18:27 -0500
        Re: Question about power capacity of electrical motors. "Robert Clark" <rgregoryclark@gmSPAMBLOACKail.com> - 2017-07-22 11:40 -0400
          Re: Question about power capacity of electrical motors. "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-07-23 14:32 -0500

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