Eddy Current Dynamometer Design

ragu4uragu4u Member Posts: 4

Its a Testing setup (Eddy Current Dynamometer) for Switched Reluctance motor.

Drum is a hollow cylinder. Drum and Pole will rotate along same axis. Drum is connected to Motor to be tested(SRM). Pole has excitations, when it excited it attract with drum. Motor rotates drum. Hence Pole also rotates with same speed.

Pole rotation is blocked and its connected to load cell for torque measurement. When Motor Rotates and pole rotates same speed with drum( same speed as motor), we can measure torque at particular speed. Then we reduce the excitation them the drum will slip from pole magnet

So particular torque we should give particular magnetic force of attraction to drum.

1. How this magnetic attraction force can calculated??

2. Is this can be simulated in ansys maxwell( with drum rotation transient)


  • nchodenchode Posts: 331Forum Coordinator
    edited October 2020


    Thanks for providing more clarity on your application (You should have replied this in your yesterdays post to avoid duplication).

    As per your application your main requirement is to find how much force will be exerted on the drum by the pole when it is energized - Please correct if this is not.

    1) How this magnetic attraction force can calculated??

    Assign excitation to the coil and assign force parameter to the drum. when you run the analysis you should be able to plot the force acting on the drum against the current. You can run parametric analysis with current as variable and figure out the amount of force acting on the drum at various current values.

    Depending on the results you can decide the number of turns and current required to pull the drum.

    2) Is this can be simulated in Ansys Maxwell( with drum rotation transient)

    Yes, you can run the transient simulation by assigning band to the drum (or all the moving objects along with drum) and defining motion setup.

    But designing the pole(electromagnet) is all what you are aiming. Simulation as explained in the first step should be enough.

    (I have a small question on the figure above. if the drum is connected to motor shaft through a bearing, which is fixed, how will the drum along with the motor move towards pole? - If you have drawn this fig. only for representation purpose its ok )

  • ragu4uragu4u Posts: 12Member

    Thank you for your valuable replay.

    I draw it for only representation.

    Drum and pole also rotating ones. Pole rotation is blocked and its connected to load cell for torque measurement. If pole attracts drum, motor torque can read in load cell. Testing motor has maximum torque, So Electromagnet should develop a Braking torque to Stop drum rotation.

    1. How this braking torque calculated using Ansys Maxwell ( I found torque curve on ansys. But its only in x,y or z direction. Drum is a rotating part. Which direction should I consider?)
  • nchodenchode Posts: 331Forum Coordinator


    You have actually confused me by saying you want to measure the force on the drum in your first post.

    What you actually want to simulate is the torque experience by the pole assembly when it is blocked. This means pole is stationary when you want to measure the torque.

    This is same as how you define a motor modal.

    Assign band to your drum and define the speed of rotation in motion setup. Then after running the analysis just plot the moving torque in rectangular plot from reports.

    Additionally you can also apply torque parameter to the pole and plot the Torque1.Torque. This will give you same torque but in opposite direction.

    Also, turn on eddy effect for the drum and pole in Maxwell 2D/3D>Excitations>set eddy effect

    Set the core loss calculation as well.

    Now coming to your question on torque direction. Torque is defined around the center axis of rotation. so the axis you need to select while plotting torque is the axis of rotation of drum/pole (it is automatically the default one).



  • ragu4uragu4u Posts: 12Member

    Thankss very much sir?

  • ragu4uragu4u Posts: 12Member

    How can I excite coil in Transient Solver. I want to give 3.6 A to coil which have 1500 conductors

  • nchodenchode Posts: 331Forum Coordinator


    Refer to the below two Maxwell help documents for more information on setting up a transient simulation

  • ragu4uragu4u Posts: 12Member

    New Error message :(.

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