AC motor control

[win_832001]

Hello there..here I have a project that required AC motor which is control by using PIC16F84.. Can anybody guide me with :

a) Idea to connect this two device - PIC and AC motor.
b) If possible, can anybody to attach a website link that can help me to solve the problem.

 

[instruite]

**broken link removed**
above link may be help you get started

 

[stevez]

Some comments or questions that might help:

A. What kind of AC motor? Single phase, 3 phase ....universal or synchronous in that RPM is tied to frequency of supply. Don't get too wrapped up in this but it does make a difference. Note if common single phase you need to worry about the starting circuit if the plan is to vary the speed.

B. By control do you mean just on or off, reverse, variable speed, multi-speed...?

C. If on/off, reverse - more or less switching tasks, are relays sufficient? If so, then PIC to relay is common interface.

D. If variable speed, do you intend to create the variable frequency/variable voltage power supply to go with it - or will the VFD be a separate system? If it is separate - what are the inteface requirements - 4 to 20 ma, 0-10 volts, some kind of serial data transfer?

Lots of questions intended to help you narrow the possibilities.

 

[win_832001]

sorry stevez..i don't mention clearly about the specification of AC motor and a control way that I need..
a. The type of AC motor that I want to control is single phase AC motor.
b. by control to just on and off and its turning bidirectional. I have idea that the motor should use limit switch to limit the rotation of the motor between 0 to 90 degree..
c. The AC motor rotate with constant speed. Is there need to create variable frequency/variable voltage power supply?

d. I also lack of example of circuit..did u have a guide on how can I get the example circuit that similar with this project.

thank you...

 

[stevez]

I'll rearrange your response a little:
A. You have a single phase AC motor
B. You want to turn it on/off and provide a reversing function.
C. You want constant speed, no need to vary. Shall we presume the design RPM - example 1725 rpm @ 60 Hz. We will presume that your normal AC mains power is the source unless you say otherwise.

In B you also mention that you want to limit the rotation to 90 degrees, one quarter turn. Is this an AC motor on a gear reducer? Explain the application just a little more. To actually operate what I consider to be a normal AC motor within only 90 degrees of rotation (unless its a gearmotor) might ruin it.

 

[Hero999]

You can't control the speed of a single phase AC motor reliably, it just isn't possible.

A single phase motor chreates two phase either by using a shading coil or by using a capacitor. Both are frequency dependant so if you change the frequency too much it will have trouble starting.