Contacts10 min read
Contact design for MCBs and MCCBs: what changes with frame size
A miniature breaker and a moulded case breaker share a job but not a contact system. A guide to force, arc control, material and calibration.
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Topic hub
Contacts, coils and electromechanical
Contacts and coils sit at the point where electrical performance becomes physical. These guides cover material choice, contact resistance, arc damage, winding, termination and the tests that prove a switching part will last.
Guides in this topic, page 2
Contacts9 min read
Contact design for switches and sockets: force, wipe and arc
A wall switch and a socket outlet look simple and fail for different reasons. The contact calls that decide life, temperature rise and plug retention.
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Contacts9 min read
Contact erosion and arc damage: life drivers and design responses
How arcing removes and transfers contact material, why make and break do different damage, and how to size an erosion allowance.
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Contacts9 min read
Coil bobbin design: wall thickness, creepage and retention
The bobbin is the coil's structure, its insulation and its interface to the assembly. Small geometry calls decide all three.
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Contacts10 min read
Coils for motor windings
Distributed, concentrated and hairpin windings do the same electrical job in different ways. How the choice changes end turns, harmonics, slot fill and the cost of a stator.
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Contacts10 min read
Contact material selection for AC vs DC switching
An AC arc gets a current zero every half cycle. A DC arc does not. That single difference reshapes erosion, welding and the material shortlist.
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Contacts9 min read
Contact plating: silver, gold and nickel compared
The finish on a contact decides its resistance, its wear life and its cost. A practical comparison of silver, gold and nickel, and the underplate that holds them together.
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Contacts9 min read
Contact welding and sticking: causes and prevention
Why closed contacts fuse, which loads make it worse, and the material, force and circuit changes that keep a contact opening.
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Contacts10 min read
Coils for transformers and inductors
Turns ratio, winding window, insulation and loss: the four calls that decide a transformer or inductor coil, and where the two designs part company.
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Contacts9 min read
Contact brazing and welding: how to choose the joining process
Resistance welding, brazing and laser welding each leave a different joint, a different heat affected zone and a different inspection problem. Match the process to the contact, the carrier and the life target.
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Contacts9 min read
Contact resistance: what it means and how to test it
Constriction and film resistance, the four-wire method, and why a single micro-ohm reading is a weak acceptance criterion.
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Contacts9 min read
Copper wire for coils: enamelled grades and temperature classes
How enamel grade, temperature class and winding practice decide whether a coil survives its own heat.
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