Product Details
CuW Moving Arc Contact
The moving arc contact is the half of the contact pair that travels when the vacuum interrupter opens or closes.
Technical Description
CuW Moving Arc Contact
The moving arc contact is the half of the contact pair that travels when the vacuum interrupter opens or closes. It shares the arc-erosion duty with the static contact, but unlike the static side it also handles mechanical impact and operator-driven motion. CuW70, CuW75, and CuW80 cover the standard grade options; geometry follows your drawing.
In a VCB build, the moving contact bolts or brazes onto the operating shaft that the breaker mechanism drives. We can supply moving contact blanks for your in-house assembly, or finished components with the interface machined to your spec. Pairs are available, see our CuW Arc Contact Pair for matched sets.
Specifications
| Property | Value |
|---|---|
| Material Grade | CuW70 / CuW75 / CuW80 |
| Tungsten Content | 70, 75, or 80 wt% |
| Form | Machined moving contact (round, stepped, or to drawing) |
| Dimensions (OD × L) | Per drawing |
| Tolerance | Per drawing |
| Electrical Conductivity | ≥42% IACS (CuW70) / ≥38% (CuW75) / ≥34% (CuW80), per GB/T 8320-2025 |
| Density | ≥13.80 / 14.50 / 15.15 g/cm³ for CuW70 / 75 / 80 |
| Hardness (HB) | ≥175 / 195 / 220 for CuW70 / 75 / 80 |
| Bending Strength | ≥790 / 885 / 980 MPa for CuW70 / 75 / 80 |
| Gas Content (vacuum switch grade) | O ≤0.008%, N ≤0.002% per GB/T 8320-2025 |
| Surface Treatment | As machined; silver or nickel plating optional |
| Working Voltage | Common MV ratings: 12 / 24 / 40.5 kV |
| Working Current | Application-specific; confirmed per design |
| Operating Shaft Interface | Bolt, braze, or weld, per drawing |
Exact certified properties for your lot are available with material documentation on request.
Applications
- Moving-side arc contact in 12 kV, 24 kV, and 40.5 kV vacuum interrupters
- MV VCB original equipment and replacement programs
- Refurbishment of installed VCB fleets requiring matched-pair contact replacement
- Moving contact assemblies for vacuum interrupter sub-suppliers building to OEM drawings
Technical Notes
Moving contacts see two duty cycles simultaneously: arc erosion at the face, and mechanical fatigue at the operating shaft interface. CuW is the right answer for the first; the second comes down to how the contact attaches to the shaft. A bolted interface is the most serviceable; a brazed joint to a copper or bronze shaft adapter gives lower contact resistance but is harder to inspect and replace.
Pair geometry matters more here than for the static side. The arc gap, contact spring travel, and surface alignment all interact with the static contact face. If you're sourcing a moving contact to replace an installed VCB part, supply the drawing for both halves of the pair or send a sample of each, small geometry deltas can change breaker behavior.
Sourcing & OEM
Custom-machined to your drawing is routine; we don't require minimum drawings. Plating, MOQ, and lead time vary by specification; contact us with your drawing or sample for a project-specific quote.
Technical FAQ
Common questions about this product.
What grades of CuW do you offer for moving arc contacts?
CuW70, CuW75, and CuW80. CuW70 is the typical default for MV vacuum interrupter duty; CuW75 and CuW80 are specified where arc-erosion resistance matters more than conductivity.
Can the moving contact be supplied with the operating shaft interface machined?
Yes. We can supply blanks for your in-house assembly, or finished components with the bolt / braze / weld interface machined to your spec. Specify the interface in your drawing.
Do I need to order static and moving contacts as a matched pair?
Not required, but recommended for new VCB builds or when replacing both halves at once. See CuW Arc Contact Pair for matched-set ordering. For refurbishment programs replacing only one half, single-component orders are also routine.
What is the typical lead time?
Lead time varies by grade, dimensions, plating, and order volume. Contact us with your specs for a project-specific timeline.
Are your moving arc contacts compatible with major VI brands?
If you supply the drawing or a sample from the existing part, we can produce a dimensional match. We don't claim direct interchangeability with named brands by reference. The drawing is the contract.
How do I request a sample for evaluation?
Email [email protected] with the drawing or specification and intended application. Evaluation samples can typically be arranged for serious sourcing programs.
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