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Re: [TCML] 50Hz = 'short end of the stick?'



On 03/29/2010 02:24 PM, Christopher Karr wrote:
Date: Mon, 29 Mar 2010 01:11:38 -0700
Subject: Re: [TCML] 50Hz = 'short end of the stick?'
From: davep@xxxxxxxx
To: tesla@xxxxxxxxxx


For example, a line frequency which is lower results in a less-efficient
transformer (weight:wattage)
     Low frequency, if designed for, is higher efficiency in
     the transformer.  Hence (as noted) the past (and, indeed,
     present) use of 25 Hz, 16 2/3, etc in specific applications.
First, I would like to ask for a reference on this subject; it seems that the opposite would be true. For example, do aeroplanes not use 400Hz transformers and 'line' frequency? Is this not because the weight of the transformers can be reduced, due to the higher frequency having a higher saturation-point in the laminations?

Or, is the type of efficiency you speak of purely electrical and in total neglect of materials expense? If that's the case, then if there are fewer voltage reversals in a given time, of course there's going to be a potential for a greater efficiency, as long as you are speaking in purely watts(in):watts(out) terms.

Thank you,

  - Christopher Karr 		 	
Go back to 1900 iron and you will find out that the prohibitive cost of thin laminations prefers lower frequencies.

that being said, today's iron is optimized for 60Hz.

in theory it shouldn't matter, but the issue is the iron loss curve does not follow the frequency to the 1.6 power, so you can't drop the frequency 16% and increase the flux 6% and figure the iron loss will be the same.
It will still be higher.

-Eldon
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