New Energy Solutions

Magnetic blowout is a critical technology for safe DC arc interruption in Hongfa HVDC relays: Operating Principle - permanent magnets create a strong magnetic field perpendicular to the contact gap

Arc Generation - when contacts open under load, an arc forms between the separating contacts

Magnetic Force - the magnetic field exerts force on the arc plasma, stretching it away from the contacts

Arc Elongation - the arc is stretched and cooled as it moves into arc chutes

Arc Extinction - the elongated arc eventually extinguishes as current drops and cooling continues

Contact Protection - rapid arc removal minimizes contact erosion and extends relay life. The magnetic blowout is essential because DC arcs lack natural zero-crossings like AC, making them harder to interrupt. Hongfa HVDC relays use optimized magnet placement and contact geometry for effective arc control. The hermetic sealing contains arcs and prevents external ignition. This technology enables safe switching of high voltage DC loads up to 1000V.

Hongfa HVDC relays with magnetic blowout are essential for safe DC switching; contact our FAE for application guidance.

Precharge circuits are essential in EV battery systems to limit inrush currents when connecting the battery to the inverter: Problem - when a high voltage battery is connected to an inverter with discharged capacitors, the instantaneous current can exceed 1000A, welding contacts and damaging components

Solution - a precharge circuit uses a series resistor and smaller relay to slowly charge the inverter capacitors before main contactor closure

Operation Sequence - 1) Precharge relay closes, charging capacitors through resistor (typically 50-100Ω), 2) After 200-500ms, capacitors are charged to battery voltage, 3) Main contactors close with minimal current, 4) Precharge relay opens

Component Selection - use HFE82 (100A) or smaller HVDC relay for precharge, HFE85/HFE88 for main contactors

Resistor Sizing - calculate based on precharge time constant and power dissipation

Safety - precharge failure detection prevents main contactor closure if precharge is incomplete. Precharge circuits protect contactors and extend system life.

Always include precharge circuits in EV battery systems; use HFE82 for precharge, HFE85/HFE88 for main contactors.

Selecting HVDC relays for energy storage systems involves several considerations: Voltage Rating - choose relay voltage rating ≥ system voltage with safety margin

for 800V systems, use 1000V rated relays (HFE88, HFE95)

Current Rating - size for maximum continuous current with 20% derating

consider peak currents during charge/discharge cycles

Switching Duty - determine if relay switches under load (make/break) or only carries current (carry only)

make/break requires full arc suppression capability

Series Connection - for very high voltages, relays can be series-connected with voltage balancing circuits

Coil Voltage - 12VDC or 24VDC to match system auxiliary power

Environmental - consider temperature range and IP rating for outdoor installations

Certifications - verify UL, TÜV, or CQC certifications for your market. For grid-scale storage, HFE95 (200A) or HFE88 (250A) are commonly used. For commercial storage, HFE85 (150A) provides good cost-performance. Contact our FAE for detailed application support.

Select HFE85 for 400V/150A, HFE88 for 800V/250A, HFE95 for 1000V/200A energy storage applications.

HVDC relays are hermetically sealed and require no maintenance during their service life. Contact resistance should be monitored periodically in critical applications. Replace relays showing increased contact resistance or welding.

Monitor contact resistance in critical applications; sealed relays require no maintenance.