speed control of 2 x 110v 2kw angle grinder motors

[SteveMR]

As the title states I would like to control the speed of 2 x 110v 2kw angle grinder motors.

I would like 5 speed settings and is there a simple solution to this I could build as a beginner?

Cheers,

Steve

 

[poor mystic]

In electric motors the current is partly controlled bt he resistance of the motor windings and partly by the inductive reactance of the windings. So although reducing the frequency of the AC supply does also lower the speed of the motor it also allows greater currents to flow - the motor becomes more and more like a short circuit as frequency is reduced. At low supply frequencies there can be large currents flowing, which are likely to damage the motor.
When supply frequency is increased, less power is available.

 

[duke37]

You could try a lamp dimmer circuit, this consists of a resistor, capacitor,diac and triac. A normal lamp dimmer will not be powerful enough so you will need a bigger triac. This will adjust the speed but will not control it with varying loads.