guess the force !!

Following the good old tradition to build something between the years I decided to make a little test setup to explore permanent magnet-coil interaction.
The first picture shows the setup.
The 3d printed contraption consists of a lever that contains on one side of the fulcrum one or more stacked strong permanent magnets which interact with a coil, as well as a container for testweights. On the other side is a counterweight, so that the lever is horizontally balanced. If a current is then applied to the coil the magnets get attracted to the coil and weight can be added to the container. The weight at which the lever tips over is equivalent to the maximum vertical force between magnets and coil.
Since the distance between fulcrum and testweight is twice that of fulcrum and magnet the testweight has to be doubled to give the actual holding force.

Two coils have been made. One is embedded in a material with permeability mu_r of 1 the other one in a material that contains about 25% ir