A permanent magnet brake is the fail-safe answer with a different physics: instead of springs pushing a disc, a neodymium magnet holds the armature by magnetic force alone. EIDE FIP applies that idea to servo and packaging drives, and its signature is what happens after release.

Why does residual torque matter in an unwinding application?

Because a web unwinder brakes with the brake and runs with it too. If the friction elements keep touching after release, the web drags, tension drifts and the printed pattern shifts. FIP releases clean: the 24 VDC coil generates a field opposite to the neodymium magnets, cancelling the attraction entirely, so the armature is free and there is no residual torque to fight the process. That clean release is also what makes the brake safe - with no current the magnets keep it firmly applied.

What makes a permanent magnet brake safer than a spring one?

Both are fail-safe, but the magnet version has no mechanical spring pack to fatigue and no adjustment to drift. The magnetic circuit generates rated braking force with no power at all, which suits safety circuits where the brake is the last line of defence. The FIP spans 0.75-100 Nm at up to 10,000 rpm, adapts to most motor manufacturers, and keeps its compact envelope - which is why it shows up in low-inertia motors, servo axes, packaging machines and building-facade cleaning equipment.