Fixed Contact: Contact Diameter 40-120 mm

Component Specifications

Definition

A fixed contact is the stationary electrode component within a medium voltage vacuum interrupter module that establishes and maintains electrical connection with the moving contact. It is designed to withstand high electrical currents, arcing during interruption, and maintain precise alignment for consistent performance in circuit breaking applications.

Working Principle

The fixed contact remains stationary while the moving contact separates during circuit interruption. When contacts open, an electric arc forms between them in the vacuum environment, which is extinguished at current zero due to the rapid dielectric recovery of vacuum. The fixed contact's geometry and material properties help control arc movement and ensure efficient current interruption.

Materials

Copper-chromium (CuCr) alloy (typically 75/25 or 50/50 composition), oxygen-free high conductivity copper base with chromium dispersion for arc resistance and current carrying capacity.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Contact Force	200-800 N
Current Rating	630-3150 A
Voltage Rating	7.2-36 kV
Electrical Life	10,000-30,000 operations
Mechanical Life	30,000-100,000 operations
Contact Diameter	40-120 mm

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

IEC 62271-100, IEEE C37.04, GB/T 1984

Parent Products

This component is used in the following industrial products

Medium Voltage Vacuum Interrupter Module

Core vacuum switching component for medium voltage circuit breakers and contactors.

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Engineering Analysis

Risks & Mitigation

Contact welding during fault currents
Excessive erosion reducing contact gap
Surface oxidation affecting conductivity
Mechanical misalignment causing poor contact

FMEA Triads

Trigger: Insufficient contact force
Failure: Increased contact resistance leading to overheating
Mitigation: Regular maintenance checks and proper spring calibration

Trigger: Contamination during assembly
Failure: Reduced dielectric strength and premature breakdown
Mitigation: Clean room assembly procedures and vacuum baking

Trigger: Material fatigue from repeated operations
Failure: Contact deformation affecting alignment
Mitigation: Regular inspection and replacement per manufacturer guidelines

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.05 mm for contact alignment, ±5% for contact force

Test Method

High current testing per IEC 62271-100, contact resistance measurement, X-ray inspection for internal voids

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

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Manufacturers of Fixed Contact

Manufacturer profiles associated with Fixed Contact.

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Frequently Asked Questions

What is the main function of a fixed contact in vacuum interrupters?

The fixed contact provides a stationary connection point for electrical current flow and helps control arc behavior during circuit interruption in vacuum environments.

Why is copper-chromium alloy used for fixed contacts?

CuCr alloy combines excellent electrical conductivity from copper with high arc resistance and low chopping current from chromium, making it ideal for vacuum interruption applications.

How does contact geometry affect performance?

Spiral or axial magnetic field contact designs help rotate the arc, preventing localized overheating and ensuring uniform contact erosion for longer service life.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Fixed Contact