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From: Taylor Jacobus on 9 Jan 2010 12:03
To test the motor I have created a three phase voltage source. I have troubleshooted the model and have figured out that when running a simple sine wave I can reset the step size for 60 hertz frequency to .001 and it follows the signal correctly for 5 seconds. The only problem is if the simulation time is longer than 5s, lets say 10s then for the first five seconds nothing is shown and the last five seconds it follows the signal. Im guessing there is a limit on the number of points or zero crossings??? Im using the ode45 solver with max and initial step sizes .001. Can someone explain to me why this is?

My end goal is to provide a reference sheet for different motors. Lets say for changing voltages. So for different voltages the motor would output a certain rotor speed. My total simulation time could be over 60s.

Any help would be appreciated. Thanks.
From: nil on 11 Jan 2010 12:20


yep you are right , its abt the number of points on the graph. i also had the same problem , what you need to do is to change the settings of the scope , you have to double click on it and then there is a place at the top where you can change the parameters of the scope . in some pllace you will see the limits of the number of points i think , you may set it to inf. ( infinity) to display the whole result.however my advice is that 60 sec is very long and the simulation can take a lot of time . why dont you use another solver?

.....hope that helps... can you manage to do it? btw i would need your help , if you know abt motors......

nil
From: Taylor Jacobus on 12 Jan 2010 15:57
"nil " <nilan29(a)yahoo.co.uk> wrote in message <hifmkn$7of$1(a)fred.mathworks.com>...
>
>
> yep you are right , its abt the number of points on the graph. i also had the same problem , what you need to do is to change the settings of the scope , you have to double click on it and then there is a place at the top where you can change the parameters of the scope . in some pllace you will see the limits of the number of points i think , you may set it to inf. ( infinity) to display the whole result.however my advice is that 60 sec is very long and the simulation can take a lot of time . why dont you use another solver?
>
> .....hope that helps... can you manage to do it? btw i would need your help , if you know abt motors......
>
> nil

Thanks! That has been killing me. If you need anything, I will do my best. I have a few papers and I am almost done with my induction motor. Let me know>
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