[Prev][Next][Index][Thread]

Re: Oil Burner Ignition Transformers

Subject:  Re: Oil Burner Ignition Transformers
   Date: Tue, 13 May 1997 06:39:21 -0700
   From: Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization: Stoneridge Engineering
         To:  Tesla List <tesla-at-pupman-dot-com>
 References: 
            1


Tesla List wrote:
> 
> Subject:  Re: Oil Burner Ignition Transformers
>   Date:   Mon, 12 May 1997 15:15:15 -0400
>   From:   "Thomas McGahee" <tom_mcgahee-at-sigmais-dot-com>
>     To:   "Tesla List" <tesla-at-pupman-dot-com>
> 
> ----------
<SNIP>

> 
> I would be interested in whether any other coiler has ever
> encountered an ignition transformer that was NOT current limited. In
> my experience they are invariably 10KV at 20 to 30 ma. Has anyone out
> there ever encountered one that was like a pole pig rather than a
> neon transformer? (By this I mean that it REQUIRED an external
> ballast.)
> 

All of the older, constant running, versions I've run into were
self-limiting. Have'nt seen (or looked for) any of the newer versions. 

> Alfred also remarked to me that every microwave transformer he has
> encountered has NOT had any magnetic shunts. This also goes counter
> to my own experience. I have ALWAYS found the magnetic shunts to be
> located between the primary and secondary, consisting of a bundle of
> iron strips wound with one or two turns of insulation and placed
> between the "O" and the "I" part of the core. Has any one else out
> there found anything different?
> 

Yeah - just this weekend! Went to a local Hamfest, and a guy sold me a
big trannie out of a commercial microwave oven - this was the Mother of
all Microwave transformers! It consisted of two identical secondary
windings wound over two primary windings, and the core measures 4.5" x
8" x 2.5", and outputs 6 KV center tapped! A filament winding was on one
leg. There was NO center core, nor was there any shunt - the laminations
were "C" type, not "E" type. This beast was basically an open-core plate
transformer. Price was $2.00 - couldn't pass it up for my boatanchor
collection! :^) 

Now until this time any of the home model microwaves I've cannibalized
(a half-dozen or so) have had shunted trannies, about half the size and
weight. I've targetted these for future tube coil work, so haven't tried
direct shorting any ala disruptive service. Have heard that the current
control in some of these is not very great, with very high short-circuit
currents being seen on at least some units. Will have to try shorting
some of these and measuring primary current at lower AC input from a
variac to see...

Safe transformations to ya!

-- Bert --