2 replies to this topic

[kram]

I would like to be able to vary the speeds of some of my power tools for different purposes. These tools are stationary and typically have 3/4 to 1 1/2 HP motor running 120V 60Hz. Simply varying the input voltage voltage only results in a complete stall and inability to restart. Any help would be greatly appreciated.

[marke]

Hello kram

There are generally two types of single phase motors used for this application. The simplest motor is the induction motor, but more commonly on small hand held tools, the universal motor is used.
With an induction motor, the speed of the motor is determined by the frequency of the supply and so in most cases, there is no easy way to vary the speed. A three phase induction motor can be speed controlled by varying the frequency applied to it, so you caould replace the single phase induction motors with small three phase induction motors and then use single phase input, three phase output speed controllers to achieve you requirements.
Universal motors ( have brushes internally) can be speed controlled by the use of a variable voltage. Ther are solid state controllers and variacs that will achieve this result.
Best regards,