[SOLVED] Controlling Speed of single phase motor

[venkates2218]

Hai,
I tried to control the speed of Single phase induction motor.The motor is reversible and we can choose the direction by chaning the tapping.
For controlling the speed i'm using Firing angle method with BTA16 TRIAC.

Full speed RPM is 750.Have to reduce this RPM to 500RPM.By varying the firing angle,I'm able to control the speed.

Let's consider,the firing angle is changed by changing the value from 0 to 100.
Initial firing angle value=24 for 500RPM

If the rpm is lesser than 490 mean firing angle will be added by one,if greater then 510 means subtracted by 1.This correction will made for every 2 seconds time interval.

It working fine,but when the rpm is low,firing angle value is increased too much,same problem for higher value also.

How to main constant RPM by changing the values.?Is there any specific method or any other algorithm is available.?

 

[Carry for cents bazar]

Please post the circuit. It should be easy to make a driver for the triac. This is an AC motor?

 

[FvM]

Please post the circuit. It should be easy to make a driver for the triac. This is an AC motor?

Circuit details are always interesting, but I presume that's not the problem here. Motor type is clearly specified in the initial post.

Suggests you review various previous threads about single phase induction motor control. Some are already linked at the bottom of this page.

Generally, stable speed control of induction motors by voltage respectively phase angle variation is only possible for certain load conditions, e.g. fans or centrifugal pumps. Speed feedback can help a bit.

The described control algorithm is a pure I controller, PI would be probably better and achieve faster reaction. Ki and Kp have to be properly adjusted and may be made speed setpoint dependend.