Hi All, I recently got a catalog from Eagle America tools. On page 49 is a router motor speed controller rated up to 3 1/4 HP or 115 Volts/15 Amperes. It is on sale for $34.99. The part # is 421-1300. Web page is at: http://www.eagle-america-dot-com/ Question: Has anyone tried this particular unit successfully on a Tesla coil? Did filters improve the performance of this unit (aka prevent it from being cooked)? Cheers, Barry