kontaktarm

Kontaktarm is a term used in electrical engineering to describe a lever or arm that carries electrical contacts and serves as the switching element within a device such as a relay, switch, or measuring instrument. The kontaktarm either carries one or more contact surfaces and is actuated by an external mechanism (solenoid, cam, or spring) to close or open electrical circuits. The design balances mechanical stiffness, contact force, and electrical resistance to ensure reliable operation and minimal wear.

Construction and materials commonly used for a kontaktarm include springy metals such as beryllium copper, phosphor bronze, or stainless steel. The contact surfaces are often plated (silver or gold) to reduce contact resistance and corrosion. The arm is typically mounted on a pivot or flexure and may incorporate a secondary contact configuration (make-before-break or break-before-make) depending on the application. Precise bending radii and surface finishes are important to minimize arcing and wear.

Applications of the kontaktarm span relays, mechanical switches, and certain measuring instruments. In relays, the kontaktarm forms part of the moving contact assembly; in switches it functions to connect or disconnect circuits; in precision instruments it may serve as a moving contact in galvanometers or impedance meters. In timekeeping devices, a contact arm can trigger events such as chimes or pulse counting.

Reliability and maintenance considerations include wear at contact points, contact bounce, and corrosion. Good design reduces arcing and wear through appropriate contact force, material choice, and plating. Worn or deformed kontaktarm components are typically replaced to restore performance.