# VFD Presentation



## CYoung (Apr 19, 2013)

Hi Guys.
First time poster, long time reader. 
I am presently in my last semester as an electrical engineering technology major. Today, I gave a test run of my final power point on VFD's and one of the questions from professor was why sensorless vector. I get the whole sensorless concept and was able to explain than no encoder/resolver was needed to supply feedback. The vector part, I didn't have an answer for. His statement was when he hears the term vector, he thinks vector diagrams. After doing some quick research, I see that their operation is based on vector diagrams and a whole bunch of math. Anyone have any suggestions on how I can explain with out adding another 20 slides?

Thank You


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## JRaef (Mar 23, 2009)

CYoung said:


> Hi Guys.
> First time poster, long time reader.
> I am presently in my last semester as an electrical engineering technology major. Today, I gave a test run of my final power point on VFD's and one of the questions from professor was why sensorless vector. I get the whole sensorless concept and was able to explain than no encoder/resolver was needed to supply feedback. The vector part, I didn't have an answer for. His statement was when he hears the term vector, he thinks vector diagrams. After doing some quick research, I see that their operation is based on vector diagrams and a whole bunch of math. Anyone have any suggestions on how I can explain with out adding another 20 slides?
> 
> Thank You


I would suspect that your prof already knows the answer, he is trying to get YOU to discover it yourself. Being able to explain it without 20 slides in a PPT is a good exercise, most of the people I talk two would not understand the math involved anyway.

To get you on the right path, do some research on a "motor equivalent circuit" diagram. From that you can see that what a motor is doing can be broken down into interactions of sub-level components such as inductance, reactance, impedance, resistance etc. (ignore the over simplifed versions). All of those interactions can be broken down further into mathematical expressions and vector algorithms. What makes a vector drive different is in its ability to measure and model the motor circuit mathematically, then apply approriate reactions. That means it has a much more powerful microprocessor than previous versions, or in some cases, a math coprocessor, to separate out and calculate the vectors of voltage, current and/or frequency that correspond to the desired effect you want to accomplish in the drive based on the performance feedback loop.


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## CYoung (Apr 19, 2013)

> To get you on the right path, do some research on a "motor equivalent circuit" diagram. From that you can see that what a motor is doing can be broken down into interactions of sub-level components such as inductance, reactance, impedance, resistance etc. (ignore the over simplifed versions). All of those interactions can be broken down further into mathematical expressions and vector algorithms. What makes a vector drive different is in its ability to measure and model the motor circuit mathematically, then apply approriate reactions. That means it has a much more powerful microprocessor than previous versions, or in some cases, a math coprocessor, to separate out and calculate the vectors of voltage, current and/or frequency that correspond to the desired effect you want to accomplish in the drive based on the performance feedback loop.


JRaef
Thanks for the response. I did some research on the equivalent motor circuit. I see what you mean as far as breaking all the individual components down. Hopefully, I will be able to get point across without confusing my self. All else fails I will fall back to the old saying "Bedazzle with brilliance or baffle with bull****" 

Once again Thanks


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