Remove Fan Hum when speed controlling?

[rive22]

This is for regular AC powered fans, not computer fans.

Anyone know how to do this? I saw a video a long time ago about soldering on some capacitors or resistors, etc. I have some industrial fans that I need to speed control to be more quiet which they do wonderfully but I need to remove the hum noise in the motor that most fans seem to make when doing this.

Would greatly appreciate any info, thanks.

 

[rive22]

Somehow found my way onto Variable output Transformers. Think I may be onto something.

 

[rive22]

Somehow found my way onto Variable output Transformers. Think I may be onto something.

This does the trick! Fantastic, smooth as ice sounding fans ahh I love it. To think all those crap speed controllers on the market make people think that's the proper way to do it.