[Boatanchors] Are 400 Hz variac's good for anything but a real 'boat anchor'
jfor at quik.com
Mon Jul 18 11:17:57 EDT 2011
You are entitled to your opinion.
> But the 7:1 guys are correct Nowhere in the thread has anyone suggested
> applying 120vrms/60Hz to a 400 Hz variac. The 7:1 factor is the required
> de-rating needed to operated a 400 Hz variac on 60 Hz in order to avoid
> core saturation.
> --- On Mon, 7/18/11, J. Forster <jfor at quik.com> wrote:
> From: J. Forster <jfor at quik.com>
> Subject: Re: [Boatanchors] Are 400 Hz variac's good for anything but a
> real 'boat anchor'
> To: "Bruce Long" <coolbrucelong at yahoo.com>
> Cc: "Bill L''Fuqua" <wlfuqu00 at uky.edu>, doc at kd4e.com, "John Hurst"
> <hurstjsj at verizon.net>, "'Boatanchors List'" <boatanchors at puck.nether.net>
> Date: Monday, July 18, 2011, 10:58 AM
> The statement is true. In a properly designed 400 Hz transformer operating
> at the rated voltage, the iron is not being saturated during any part of
> the cycle.
> If you go to 60 Hz with the same applied voltage, the iron will be
> hopelessly saturated, and it's incremental permeability will drop to near
> that of free space. It's like the iron just vanished.
> The magnetizing current will go up far, far more tha 7x.
>> "The magnetizing current @60 Hz will *much* higher than 7 times the
>> at 400Hz."
>> Please explain- justify.
>> I agree with the 7:1 guys on this.
>> Basically the issue arises in the electronic speed/torque control of
>> induction motors. Bruce KJ3Z
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