Abstract: A muzzle switch connected to the rails of an electromagnetic launcher to divert post-launch rail current into a dump resistor or other load and to prevent arcing at the muzzle. The switch includes shorting members electrically connected to the launcher rails together with a flexible washer-like ring which surrounds the rails and is in close proximity to the shorting members. Part of the rail current is diverted through the ring and when a current carrying armature which propels a payload along the rails passes the switch the interaction of the magnetic field produced by the rail current and current in the ring forces the ring against the shorting members, thus closing the switch as the armature leaves the rails.

Abstract: A homopolar dynamoelectric machine is provided with a rotor having a central axis and being mounted for relative rotation with a stator structure that supports a field coil encircling the rotor and has a main pole piece for directing magnetic flux produced by current flowing in the field coil into a first section of the rotor. Brush assemblies which are capable of making sliding electrical contact with a current collection zone of the rotor extend longitudinally adjacent to that current collecting zone and include a plurality of contact elements. These contact elements are packed in an increasing density in a longitudinal direction from one end of the brush assembly to the other end. The use of a variable packing factor for the contact elements of the brush assembly results in more uniform heating of the rotor in the current collecting zone, thereby minimizing the peak rotor temperatures and permitting the machine to operate for longer time periods.