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Induction machine how to provide load torque

0 votes
Hi there,

To specify the load torque of the open stator coils induction machine, I was attaching a 'controlled torque' block at the what seemed to be the output terminal of the machine, as shown in the attached image. I assumed this was load torque in Nm units. I now have a feeling that this is incorrect, because:

a) When I view the electrical torque output, it settles at a different value at steady state. It is supposed to settle at the load torque value

b) When I give a negative value of controlled torque, the machine does not seem to go into generator action. I'm expecting an angle between 90 and 180 degrees between voltage across terminals and current through machine during generation.

Please guide me on how to proceed.
asked Jan 31 by archie1112 (21 points)

1 Answer

0 votes
Hello archie,

you meet the same problem that i have ever met. and i try many times cannot solve it, so i make the modification of the motor model. you can have a try and see if this can help you.

1. right click the motor model ---subsystem--break the library link, then unprotect the motor model

2. go under the subsystem and "add" a load to the mechanical subsystem

see the bild below.

best regard

answered Jan 31 by yanshaofei333 (56 points)
Dear Shaofei,

Thank you for your good answer. Thanks for showing me how to modify inbuilt blocks. Your treatment will give right answer. However, I realized that it was equivalent to my approach of using a controlled torque source. I had been saying that electrical torque output will equal load torque at steady state using the relation Te=Tl+J(dw/dt)+Bw, since from class I've been used to neglecting the friction term B as being very small. However, in the inbuilt model, the friction value is '1' by default, which is why my electrical torque output was settling at a different value depending on the speed of rotation.

How do we find the power rating of the open end winding machine model? Rated voltage, power output..?