Re: [Amps] Shock hazard?

[Will Matney <craxd1@ezwv.com>]

Speaking of transformers, I'm always looking for new-old books on them, 
and found one of interest to several on here. The title of the book is 
"Electronic Transformers And Circuits", 2nd edition. It was written by 
Reuben Lee, copyright 1947 & 1955. The library of congress catalog 
number is 55-10001. Reuben Lee was an advisory engineer for Westinghouse 
Electric. The book was written after Hipersil C-cores came out and has 
good information on them. This is the first book I've found with 
information on Hipersil cores. The only other that I know of would be 
old catalogs from Westinghouse. The trade name "Hipersil" is not 
produced anymore. I'm not sure who bought the name from Westinghouse. 
Magnetic Metals make the exact type with a different trade name for the 
steel named Microsil. The two major things to use in transformer 
formulas using Hypersil steel is the flux density (B) and the stacking 
factor (K). According to the book, Hipersil has a flux density of 17,000 
gausses (17 kilogauss) and a stacking factor of 95. The book discusses 
the difference between M-15 steel and Hypersil where M-15 is a non-grain 
oriented steel and Hypersil is a grain oriented. By todays standards, 
Hypersil is about the same material as M-6. Most transformers using EI 
cores use anywhere from M-19 to M-15, and M-6 for high efficiency 
transformers.

The big downer about the book, and it is a dilly, is they don't show one 
formula for sizing the core! They have every other formula except this 
one. They reference this by saying one can use experience to determine 
the size. Of course this is not a good idea and there is three main 
formulas for calculating the cores cross sectional area. The rest of the 
information is up to date and good though. To see how to size C-cores, a 
good book to get is the C-core catalog from Magnetic Metals.

Best & 73's

Will Matney



Tony King wrote:

> At 03:50 PM 11/12/2004, Harold B. Mandel wrote:
>
> > Dear Will,
> >
> > Let's see, the a.c. cord is probably not polarized, so that means the
> > chassis can either be hot or neutral, depending upon the insertion.....
>
>
> Looking at the pictures, the line cord doesn't appear to be grounded.  
> In the 7th picture you can clearly see the line cord attached to a 5 
> lug terminal strip with two of the lugs attached with rivets to the 
> chassis.  The line cord is not attached to one of those. One would 
> hope that the applied line voltage goes to transformer windings. Of 
> course a 3 wire cord would help but without it doesn't necessarily 
> mean there is a dangerous condition.
> <snip>
>
> 73, Tony W4ZT
>
>
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