Rotational Frequency and Surface Velocity of Rolls Wrong When Pass Velocity Given

[axtimhaus]

• Two Pi in Roll.surface_velocity Hook missing
• Connection between Roll.surface_velocity and different radii of roll unclear (working or max radius?)

[ChRen95]

surface_velocity is defined as:

self.rotational_frequency * self.nominal_radius * 2 * np.pi

Where do you see a missing 2 Pi?

Second question I don't see different radii. Is it because we use working_radius for the neutral angle?

[axtimhaus]

The other way round

@Roll.rotational_frequency
def rotational_frequency(self: Roll):
    return self.surface_velocity / self.nominal_radius

The question is the connection to RollPass.velocity, which is commonly approximated using the working diameter, but currently implemented using Roll.surface_velocity

[ChRen95]

Now I see. I would suggest to use working radius. That would increase the velocities, maybe @msch67 @mscImf has another idea but I always thought from his lectures that the working radius is connected to the neutral point.

[ChRen95]

I recently encountered a problem witch was brought up by ESF. They set the machine speed using the working radius. Therefore we should use the working radius as well.