[bluffbeach]

I have been collecting for the last few years and am finally getting serious about building my larger layout. I have collected 3 transformers and am rewiring them now in preparation. The RW(110 watts) has always had a low hum and I have used it lightly over the last few years. The 1033(90) is quiet as a church mouse and the KW(190) has a pronounced hum.
I have never used the large ones before. Do I need to be concerned with the mum or it it normal for them? Seems the hum decreases slightly when they have a little load.
Appreciate any comments will be appreciated.

 

[Dennis461]

Q. Do you know why transformers hum?




A. They don't know the words!

 

[Big Ed]

Most hum some. Some more then others as something may be a little loose inside.
It can be due to loose winding or lamination's of the transformer core.
Some "hum" more then others, if it gets real hot, is the time to investigate.

 

[D&J Railroad]

You mentioned that you were rewiring the transformers. What do you mean by that? Are you rewrapping the wire around the transformer core?

 

[T-Man]

The KW has two brackets holding the plates. The tighter they are the lower the hum.

 

[cid]

A. They don't know the words!

Elect Engineering joke....

 

[highvoltage]

Hum is normal. Magnetic fields produced by the windings set up vibrations in the plates. As mentioned if they are tightly secured, they will hum less.

 

[Tranz4mr]

They all hum a little bit. The way the core is constructed makes it hum more or less. In older Lionel transformers the steel plates In the core are loosely stacked and they will hum some. More if they aren’t restrained well. In newer versions of Lionel transformers the layers are stacked, drilled, riveted into 2 solid parts that the coils or windings slip onto. The 2 parts are glued and Then pressed together making them very quiet. That is unless the glue fails then the hum is really loud. KW’s and ZW 275’s come with both types of cores.

 

[DonR]

Even those huge power company transformers hum...it's the theme song
of Alternating Current...You'll notice that every transformer hums at the
same pitch...60 cps in the Americas.

Don

 

[bluffbeach]

You mentioned that you were rewiring the transformers. What do you mean by that? Are you rewrapping the wire around the transformer core?

Hope all see this. I did not get notifications about more replies after the guy looking for the words. Came back to share what I found on Classic Toy. Same thing y'all tried to tell me. Another tidbit though; I was looking for the difference in the ZW transformers. Seems they were all the same power with the later ones having better better (riveted) stacks. Your explanations explained all my different hums and resolved my worries about safety. Thanks!
ps. My rewiring was only putting new power cords on. Most of the older ones have cracking cords. Rewrapping a core is way beyond me.