speed control

[sabu386]

Has anyone tried a router speed control on a grizzly or simular knife grinder. 3450 on a 10 inch drive wheel sounds a bit fast to me.

 

[89diesel]

You can only use a speed controller on a DC motor. The only way to control the speed on an AC motor is to use a VFD (variable frequency drive) but the cost of these units is usually prohibitive.

 

[silver_pilate]

With the small and cheap speed controls for AC motors, you sacrifice all of your torque and it just won't work for a belt grinder that needs torque to turn the belt against the work piece.

There's just no way to slow the Grizzly down without some good ingenuity and engineering.

--nathan

 

[sabu386]

Seamed too simple to work. Are routers rectified and are actually dc motors?

 

[65535]

Routers and a lot of handtools are field wound universal motors. AC/DC. They lose a ton of torque. DC motors lose torque unless a proper driver is used.

DC motors can be controlled with constant torque with a proper driver.
1PH AC motors lose torque fast, and risk overheating when slowed.
3PH AC motors can be speed controlled with a VFD for constant torque.

I worry a lot of people just throw out the term VFD and motor without knowing what exactly works.

I never did understand exactly why you would want to slow down a router very much.

 

[sabu386]

Router turn 25000 rpm which is fine with small diameter bits. when you install a 3 inch diameter pannel raiser you have or need to slow it down.