[AMPS] parasitics

Tom Rauch w8ji.tom@MCIONE.com
Fri, 22 May 1998 23:08:37 +0000

> Date:          Fri, 22 May 1998 20:20:26 -0400 (EDT)
> From:          km1h@juno.com
> Subject:       Re: [AMPS] parasitics
> To:            amps@contesting.com

Ian Wrote:

> >Nobody has come up with a real explanation of how the forces necessary
> >to bend a filament are generated, applying the same principles as an
> >electric motor. 

I posted the force levels about six months ago, when a discussion 
about filaments breaking from current and magnetic fields was posted.

The worse case total force from filament wire to filament wire was 
7.65 grams for thirty amperes in a 572B filament. 

To put this in perspective, consider the "great forces" in a meter 
movement. A single turn winding takes dozens of amperes to produce a 
few grams of torque against a very strong field magnet. It takes a 
 a lot of ampere-turns in a close area with a very dense field 
(generally concentrated by an iron core) to get strong forces.

Try to build a motor with air core coils, and see how well it works. 
Now consider what the tube looks like.....

73, Tom W8JI

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