hardening of the transformer winding

[MacIntoshCZ]

Hello,
I need to harden the transformer winding. At low frequencies, I think the winding is buzzing due to magnetostriction. Any congestion? Thanks

 

[Nigel Goodwin]

As far as I'm aware you simply soak the windings in varnish.

 

[MacIntoshCZ]

As far as I'm aware you simply soak the windings in varnish.

Varnish... hmmmmmm =)

 

[crutschow]

The noise is likely coming from the transformer laminations, not the windings.

 

[ronsimpson]

In yokes for CRT monitors we heated up the copper until the insulation just started to milt. This holds the wire in place.
We passed current in the windings to create heat. We did not do this with transformers.
Probably does not help. RonS

 

[MacIntoshCZ]

I am also thinking about liquid resin, what do you think?

 

[Nigel Goodwin]

The noise is likely coming from the transformer laminations, not the windings.

The varnish soaks in those as well.

 

[Diver300]

I silenced one transformer by heating heating it up in molten candle wax, so all the gaps were full of wax and the laminations couldn't move.

 

[ChrisP58]

Vacuum impregnation is often used to ensure the varnish gets deep into all the gaps and cracks.

 

[Nigel Goodwin]

Vacuum impregnation is often used to ensure the varnish gets deep into all the gaps and cracks.

Rather difficult to do at home, and it sounds like he's currently doing nothing to stop vibration?.

 

[MaxHeadRoom78]

A couple of methods often used is bead of weld across the laminations, another is long small dia bolts through the laminations in each corner, with the bolt insulated by bushing.

 

[ronsimpson]

transformer .................................. in molten candle wax

That way when it catches fire there is plenty of fuel.

 

[Nigel Goodwin]

That way when it catches fire there is plenty of fuel.

 

[throbscottle]

Homo Ludens is the best source of hobbyist info about transformers. http://ludens.cl/Electron/trafos/trafos.html He mentions transformer/impregnation varnish in several places on this page. Worth a read.

 

[Diver300]

That way when it catches fire there is plenty of fuel.

There really wasn't much wax that remained in the transformer. They don't have much free space.

 

[ronsimpson]

There really wasn't much wax that remained in the transformer. They don't have much free space.

If the windings were as neat a can be. The wax will be 25% and copper will be 75% of the winding area.
I was joking. I have seen fires and adding fuel seemed a bad idea.

 

[unclejed613]

That way when it catches fire there is plenty of fuel.

i once worked for a manufacturer that used transformers that had been dipped in some kind of wax... my guess is, to meet UL requirements the wax had some kind of flame retardant in it...

 

[Reloadron]

A couple of methods often used is bead of weld across the laminations, another is long small dia bolts through the laminations in each corner, with the bolt insulated by bushing.

Same and then they went into an impregnation tank of varnish. Vacuum, pressure, vacuum, pressure several times over. Something pretty cool was watching the process. When we would pull vacuum the varnish would actually boil. Anyway after cycles of vacuum pressure they went into an oven and baked. Pretty long process overall but it got it done. Years ago I worked with aircraft 400 Hz stuff. When large transformers would whine the technicians would wedge a wood block against the laminations and hammer it down till things got quiet. .

Ron

 

[gary350]

When I worked for the Transformer factory we used polyurethane on copper wire windings. NEW transformers were very slowly lowered into a tank of polyurethane for about 12 hours so air had time to escape while polyurethane replaced the air. Then transformers were drained and baked in a oven until polyurethane was dry.

When I make transformers at home on my lathe I hand paint polyurethane onto each layer of wire with a brush. Big wire air dries easy in warm weather about 1 week with no oven. Smaller wire does not dry as quick.

If your trying to refurbish and old transformer you might be ok to hand paint it with polyurethane, let it soak in then paint it several more times & soak in several more times.