CJ

Transformer Processing
« on: October 05, 2019, 02:36:07 AM »
the first job you get if hired by a transformer shop is processing.

why? it is the dirtiest, smelliest,  and most disgusting job in the shop,

if your lucky, business picks up and they hire a new guy for processing and you get to cut core or do assembly, if you graduate from that you go to hookup.

if you have special skills you get to be a winder.

why is processing the worst? well, you are working with the varnish tank, solvents to clean varnish, like trichloroethane which is rapidly being phased out of production for reasons that need not be explained,

also used in the processing dept are end capping epoxies , used to seal off the edges of high voltage coils to prevent arc over and corona, the coils are stood up in a sand box, sand is poured into the tops of the coil margins to provide a dam for the epoxy, then the epoxy is mixed, usually a two part resin (sticky stuff)mixed with some type of powder to make "mud".  then the brown mud is carefully poured into the coil tops, any spills have to be cleaned up or the epoxy hardens to the coil cover and when it is removed, the insulation rips out and the boss gets mad,

other messy processing jobs include pulling a vacuum on transformer tanks and sucking transformer oil into the tank after a 24 hour vacuum to suck out moisture,  usually the oil was Shell Diala, which was stored in a big tank out back, if it got on your clothes or in your hair it would take three washings to get rid of it,

smaller high voltage units used Dow Silicone oil which has superior insulating qualities and is non flammable, unlike the Shell mineral oil. 

so varnish, solvents, oils and epoxies, throw in an oven to bake the varnish impregnated transformers and you have one gross job! glad i got out of there and on to the core chopping machine, which made enough noise to allow me to crank the  radio way up in the back room,

anyway, how do you process a transformer if doing DIY work at home?

get a toaster oven at the Goodwill, line the rack with tile, bake the transformers for 2 hours at 200 to dry them out and also to heat up the varnish so it flows easier into the center of the windings, take out the the transformers and dip them in a can of spar varnish, make sure you do not use water based products, i use minwax gloss spar varnish, 

next, bake the transformers overnight at about 175 degrees F,  i run an extension cord way out back because it smells to high heaven when the solvents are being baked off, these vapors have a nasty habit of finding there way into the house if not set out about 50 ft,  even then, i have to keep the windows close for a few hours until the main fumes have been burned off,  make sure of the temp otherwise you will leach the colors out of the hookup wires, or if really hot, damage the PVC insulation.

scrape off the varnish globs while the transformers are still hot, and you are done.

endbells?  phosphate clean them, wipe them down, put them in the toaster oven at 150 F for 1/2 hour, pull them out and paint them with rattle can enamel, put them back in the oven for 2 hours and you will have a scratch proof finish without having to wait over night, or even a week if you put the paint on too thick.

here is a  processing table i made out of an old freezer rack and a piece of junk furniture, varnish is stored in a jar as the lid provides a better seal so the varnish does not scab over, Twinnings Earl Grey cans are the way to go for dipping, and Stouffers Lasagna plastic microwave dishes work great for disposable baking dishes ,
« Last Edit: October 05, 2019, 02:43:36 AM by CJ »
If I can't fix it, I can fix it so nobody else can!
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gyraf

Re: Transformer Processing
« Reply #1 on: October 08, 2019, 03:34:51 AM »
Thanks. Really appreciated.
..note to self: don't let Harman run your company..

alexc

Re: Transformer Processing
« Reply #2 on: October 18, 2019, 10:23:55 PM »
Lol,  the 'alpha and the omega'    ....    first job is 'transformer processing'   ....  last job is  'transformer CJ-ing'   :)

I mean, one doesn't just give over iconic vintage transformers to just anybody to 'detail-document' or 'CJ-ing' as the term is in the modern engineering parlance!
I ping therefore I am


 

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