Transformer Noise source & cure

Well, the hum is the vibration of the coils and the laminations of the transformer.  Make sure the core and the windings are mounted solidly and nothing can move.

Even after you do that, some transformers are louder than others.

Thanks John!  This one seemed to get louder after I worked on it (maybe the ambient noise just went down...)  Have you ever tried and had success in making one quieter?  If so, how'd you do it?  Thanks again,

S/F Mike

It's hit or miss trying to quiet them.  I used some wooden shims between the coil and core on one that helped, but it actually made another worse!  I know a guy that dipped the core in varnish to quiet one, but I'm not willing to go to all that trouble.

Try dipping it in Paraffin. They do that for guitar pickups.

That's what the lacquer is for, but it's a PITA to remove the core and dip it!  I can't see Paraffin being any less trouble, and I suspect the lacquer would penetrate farther to do more good.

Another issue is you have to keep the area the rollers or sliders contact free of any coating.

What model is the transformer?

John:

Fender and Gibson have been potting ( dipping in paraffin ) for over 60 years, but what do they know!

I didn't say it wouldn't work, just that it would be messy. Of course, dipping the transformer in anything is bound to be a bit messy. 

Of note is that the core of these transformers will also get a lot warmer than a guitar pickup, and the paraffin might melt during extended operation.  Paraffin melts at around 100-120F, and I can imagine transformer cores easily exceeding that in operation.

I would not recommend paraffin, as I would expect it would melt from the heat generated by the transformer.

Here's a fix.

http://www.tranz4mr.com/Tranz4..._Type_R_Hum_Fix.html

I wonder if dipping the older core in lacquer would help?

Thanks John & all,

(This is on a Lionel LW) I used some fiber gasket material between the core and the laminations on one side that had a gap and I used some card stock between the laminations and the transformer frame and it worked!  Just to be sure I applied the technique to a second LW on my layout that I had just accepted to be a "loud one" and it also is much quieter now. 

Thanks so much for the insights & ideas.  I can always count on this forum to provide the help I need when I get stuck!

S/F Mike

American Flyer used wood shims in their transformers. When an AF transformer gets too loud first thing to do is to tap the 2 shims in farther. Might work in an LW.

It was hit or miss for me, but it's been a long time since I tried it.  Worked some of the time...

I would listen to Kent S. (Tranz4mr)   He has a very nice website; some of which is dedicated to transformers and their repair.  Sorry this information has been a while in coming...  I've been to the site before but for the life of me, I could not find it quickly.  Its added to my favorites now!

Best,

Dave

I think you will find the paraffin is used to prevent wood from absorbing moisture. I have boiled lots of hard maple in paraffin to make it in to insulators.  it is used extensive on old railway equipment.  Also on marine applicants. I have seen paraffin treated maple insulators still in service after 100 years.  The problem with dipping the laminations into varnish is that it would have to be baked to get to harden in the small airless voids between the iron strips. Modern motor shops would use an epoxy to get the material to harden without air.  They would also draw a vacuum on the part to get the air out of the cracks so the epoxy would flow in, then apply pressure to drive the epoxy in.  You might want to take the core to a small motor shop and see if they can do a VPI treatment on it. 

That's probably way too much trouble and expense for an old transformer!