Power Feedthroughs are a specialized class of electrical feedthroughs engineered to transmit high voltage (kV) or high current (A) into vacuum chambers. Most MDC feedthroughs feature exposed conductors on both the air- and vacuum-sides, with optional air- and vacuum-side connectors (sold separately unless noted).

MDC Power Feedthroughs are widely used in vacuum furnaces, sample heating, biasing, in-vacuum coating systems such as electron beam evaporation, resistive heating evaporation, and DC plasma sputtering.

Electrical ratings depend on factors such as insulator dielectric strength (kV/mm), geometry, and system pressure. All MDC catalog products are rated for conditions with one side in dry atmosphere and the other in vacuum to 1x10⁻⁴ Torr (0.00013 Pa). Users should allow for operational variations and adopt safety precautions when operating at elevated voltages and currents.

Strike, Puncture, and Creep Distances define electrical performance:

Strike Distance: Line-of-sight gap between potential and ground (geometry dependent).
Puncture Distance: Distance through the ceramic insulator bulk (depends on dielectric strength and thickness).
Creep Distance: Path along ceramic surface between potential and ground (dependent on surface condition, geometry, and environment).

Electrical Performance Optimization

Extended ceramic surfaces maximize Strike and Creep.
Convoluted ceramics provide greater surface path length in limited spaces.
Glazing (high-temperature glass coating) reduces surface roughness, minimizing contamination and improving Tracking resistance.

Conductors are available in multiple materials:

Copper: Highest current-carrying capacity, poor corrosion resistance.
Stainless Steel: Good corrosion resistance, limited current rating.
Nickel: Excellent corrosion resistance, medium current capacity.

Water-Cooled Feedthroughs

For high-power applications, water-cooled designs use grounded, closed-loop cooling with non-conductive coolants (e.g., deionized water or ethylene glycol). Tap water may be used if properly grounded and piped through non-conductive tubing (polypropylene). Cooling performance depends on flow rate (L/min) and heat dissipation capacity (W/°C), and must be tailored to application requirements.

Industry applications

Power Feedthroughs are essential in industrial, research, and manufacturing systems where high voltage or high current must be safely delivered into a vacuum environment. Applications include vacuum furnaces, thin-film deposition, plasma sputtering, resistive and electron beam evaporation, semiconductor fabrication, particle accelerators, and advanced materials research. Their robust construction and safety-focused design make them ideal for high-performance, high-reliability operations.