# HELP”

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### #1 VICTOR

VICTOR

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Posted 12 November 2003 - 06:16 PM

HELLO”

I AM A NEW MEMBER AND I NEED TO FIND A CONTROL POWER FACTOR CIRCUIT BASED MICROCONTROLLER.

THANKS

### #2 marke

marke

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Posted 12 November 2003 - 07:10 PM

Hello Victor
Welcome to the forum.

There are many microprocessor based controllers for automatic power factor correction available. I am sure that your local supplier of power factor correction capacitors can supply one to you.

Best regards,

### #3 VICTOR

VICTOR

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Posted 13 November 2003 - 11:15 AM

THANKS MARKE, BUT I LIVE IN A SMALL TOWN, AND THERE IS NOT DOCUMENTATION ON THE TOPIC, I AM STUDENT I NEED TO FIND THIS CIRCUIT FOR MY PROJECT END OF CAREER.

THERE ARE NOT CIRCUITS THAT YOU CAN HELP ME?

BEST REGARDS

### #4 marke

marke

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Posted 13 November 2003 - 07:47 PM

Hello Victor

Sorry, I do not know of circuits freely available that you can copy, however, this is not a difficult task to design. (I presume that you are expected to do this rather than copy one!)
Firstly, I would make the assumption that you are measuring displacement power factor on a single phase, (makes life easier) and there fore you are not concerned about the shape of the waveform. I would use a comparator on the voltage input to give a square wave output, high when the input is posative and low when the input is negative, or to put it anotherway, you are indicating the polarity only. I would use a current transformer on the same phase and terminate it with a suitable shunt, then use a comparator to indicate the polarity of the current flow. Take the output of these two comparators and measure the percentage of the time that they are at the same polarity. This can be done with a simple RC circuit and an analogue meter, or it can be done using conters in a microprocessor, your choice. That is one easyway to make the power factor measurement. From the output of this, you can then make decisions in software on relay control etc.

Hope this helps,
Best regards,

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