Hello,
I would like mach to control my spindle speed.  Ive herd people talk about vfd's and stuff.  but i know nothing about them.  If anyone can point me in the right direction it would be great.

I have a 3.25 hp porter cable router.  About the only thing i know about it is it pulls 120v and 15 amps.  Right now its hooked up on a solid state relay to control on and off. 

Thanks,