Product Details
CuCr Contact Disc
The CuCr contact disc is the geometry that does the work inside a vacuum interrupter.
Technical Description
CuCr Contact Disc
The CuCr contact disc is the geometry that does the work inside a vacuum interrupter. The grade (CuCr25 or CuCr50) sets the material behavior; the disc geometry sets how the arc is controlled across the contact face. At higher current ratings, a flat butt contact concentrates the arc and erodes unevenly, so the disc is shaped to spread the arc. Either with an axial magnetic field (AMF) that diffuses the arc, or a radial magnetic field (RMF) that drives it to rotate.
We machine CuCr contact discs to drawing in all three geometry families, flat butt, AMF, and RMF / spiral, in CuCr25 and CuCr50. For grade selection, see CuCr25 and CuCr50.
Specifications
| Property | Value |
|---|---|
| Material Grade | CuCr25 or CuCr50 per GB/T 26867-2011 |
| Geometry | Flat butt / AMF (axial) / RMF / spiral (radial) |
| Disc Diameter | Per drawing |
| Disc Thickness | Per drawing |
| Tolerance | Per drawing |
| Surface Finish | Machined contact face; finish per drawing |
| Slot / Coil Features | AMF coil, radial slots, spiral petals per drawing |
| Stem Interface | Flat or recessed for brazing to conductive stem |
| Material Certification | Per lot on request |
Exact certified properties for your lot are available with material documentation on request.
Applications
- AMF contact discs for higher-rated vacuum circuit breakers (arc diffused across the face)
- RMF / spiral contact discs for medium-rated breakers (arc driven to rotate)
- Flat butt contacts for lower-rated breakers and contactors
- Replacement contact discs for installed vacuum interrupter designs (to drawing or sample)
Technical Notes
The choice between AMF and RMF geometry is about how the breaker manages the vacuum arc at its rated current. AMF (axial magnetic field) designs use a coil or slotted structure behind or within the contact to generate a magnetic field along the arc axis. This keeps the arc diffuse and spread across the whole contact face, which is favored at high current ratings because it limits local overheating. RMF (radial magnetic field) designs use spiral or petal geometry to drive the arc to rotate around the contact, sweeping erosion around the face rather than letting it concentrate. Both work; which one a breaker uses is a design decision by the interrupter manufacturer.
Disc machining of CuCr is straightforward but the contact face flatness and the stem-interface geometry matter for braze quality and contact alignment in the assembled interrupter. We machine to your drawing's flatness and tolerance callouts. For AMF and RMF discs, the slot and coil geometry is reproduced from drawing. These features are what create the magnetic field, so dimensional fidelity matters.
Whether you specify CuCr25 or CuCr50 for the disc follows the same logic as the material grade choice: CuCr25 for conductivity-dominated distribution duty, CuCr50 for interruption-dominated severe duty.
Sourcing & OEM
Send the disc drawing with grade, geometry family (butt / AMF / RMF), diameter, thickness, and stem interface. We'll confirm feasibility and quote. Sample-based reproduction is available where only a physical contact exists.
Technical FAQ
Common questions about this product.
What's the difference between AMF and RMF contacts?
AMF (axial magnetic field) contacts generate a magnetic field along the arc axis to keep the arc diffuse across the whole face, favored at high current ratings. RMF (radial magnetic field) contacts use spiral or petal geometry to drive the arc to rotate around the face. Both spread erosion to extend contact life; the choice is the interrupter designer's. We machine either to drawing.
Can you make the contact disc in either CuCr25 or CuCr50?
Yes. Specify the grade with the disc drawing. CuCr25 for distribution duty where conductivity matters; CuCr50 for severe interruption duty. See CuCr25 and CuCr50.
Can you reproduce a contact disc from a sample?
Yes. Send the physical contact; we can scan, measure, and machine to a drawing we generate. Customer parts are treated as confidential during quoting.
How flat does the contact face need to be?
Contact face flatness affects both braze quality to the stem and contact alignment in the assembled interrupter. We machine to your drawing's flatness callout. If you don't have one, tell us the application and we can advise a typical tolerance.
Do you supply the disc pre-brazed to the stem?
Yes. Contact disc brazed to a copper or copper-alloy conductive stem as a sub-assembly is routine. Specify both drawings.
What is the typical lead time?
Lead time varies by geometry complexity (butt vs AMF / RMF), grade, dimensions, and quantity. Contact us with your specifications.
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