I want to control the speed of induction motor single phase (about 1.5 kw / 2 hp \ 220 volt \ 50 hz and 1400rpm) using dimmer(triac) , i try this circuit i chang the value of C1 to get best control the circuit worked acceptably but not very well , not requested i Noticed that the range of control the speed with variable resistance R1 is tight and when i Reduce the Speed the motor have some noise
1-how i can solve the proplem of the thigt range of the control speed?
2-how i can solve the proplem of the noise in the motor?
3- what the Disadvantages and Damage of this kind of control on the motor? and by this kind of control As a result i reduce the voltage so the torque will be reduce , are i am right ? so what is the benefits?
for circuit Rs= 27 Ω ,5 watt and c1 = 300nf ,400volt and the load is the motor and triac is bta41

 

 

The suitable answer for a 1ph motor of this size is to use a 3ph motor on a VFD, using 1ph supply.
1ph motors, especially of this size, do not control well, even with a 1ph VFD, which are not that popular.
They tend to drop out of run at low speed or on a load.
Smaller PSC motors or shaded pole motors will, but these are generally 1hp maximum.
Max.