HJC (Huarong) Film Capacitors

HJC offers both polyester (PET) and polypropylene (PP) film capacitors with different characteristics: 1) Polyester (CL series) - Higher capacitance density, lower cost, good for general purpose applications, temperature range -55°C to +105°C, higher dielectric losses (tan δ ~0.5%), 2) Polypropylene (CBB series) - Lower losses (tan δ ~0.01%), better for high-frequency applications, more stable capacitance over temperature and time, temperature range -55°C to +105°C, higher insulation resistance. Selection guide: Use polyester for cost-sensitive general applications, LED drivers, and coupling

use polypropylene for high-frequency switching, resonant circuits, and precision applications where low loss is critical.

Choose polyester for general purpose and cost-sensitive applications; choose polypropylene for high-frequency and low-loss applications.

Self-healing is a key feature of HJC metallized film capacitors. When a dielectric defect or overvoltage causes a localized breakdown, the metallized electrode vaporizes around the fault point, isolating the defect and restoring insulation. This process: 1) Occurs in microseconds during voltage transients, 2) Removes only micrograms of metallization, 3) Does not significantly affect capacitance for minor events, 4) Allows the capacitor to continue operating normally. Benefits include: 1) Extended lifetime compared to non-healing types, 2) Graceful degradation rather than catastrophic failure, 3) Tolerance of occasional voltage transients. However, repeated overvoltage events can gradually reduce capacitance. HJC film capacitors typically show <5% capacitance loss over 100,000 hours of operation due to self-healing events.

Self-healing provides reliability benefits; monitor capacitance over time to track gradual degradation.

HJC recommends voltage derating for film capacitors: 1) DC Applications - Operate at 70-80% of rated DC voltage for long life, 2) AC Applications - RMS voltage should not exceed 50-60% of rated DC voltage, 3) Pulse Applications - Peak voltage should not exceed rated DC voltage. Benefits of derating: 1) Reduced self-healing events, 2) Longer lifetime, 3) Lower leakage current, 4) Improved reliability. Example: For 310V DC bus (rectified 220V AC), use 450V or 630V rated capacitors. For 480V AC line filtering, use capacitors rated 1000V DC or higher. Unlike electrolytics, film capacitors do not have a wear-out mechanism from voltage stress, but excessive voltage increases self-healing activity and gradual capacitance loss.

Use 70-80% voltage derating for DC, 50-60% for AC; higher derating extends lifetime and reduces self-healing.

HJC film capacitors have different failure modes than electrolytics: 1) Capacitance Loss - Gradual reduction due to cumulative self-healing events, typically <5% over lifetime, 2) Insulation Resistance Degradation - Slow decrease over time, especially at high temperature/humidity, 3) Open Circuit - Rare, caused by severe overvoltage or mechanical damage, 4) Short Circuit - Very rare due to self-healing

only occurs with severe sustained overvoltage. Unlike electrolytics, film capacitors: 1) Do not have electrolyte to dry out, 2) Do not have defined end-of-life from wear-out, 3) Can operate for decades with minimal degradation. Warning signs: Capacitance drop >10% from initial value, significant increase in tan δ (dielectric loss), visible case damage or swelling.

Film capacitors are highly reliable with no wear-out mechanism; replace if capacitance drops >10% or physical damage is visible.

Yes, HJC CBB61 series film capacitors are specifically designed for motor run applications. Features include: 1) AC Voltage Rating - Rated for continuous AC operation (typically 250V, 370V, 450V AC), 2) Self-Healing - Metallized film construction handles voltage transients during motor starting, 3) High Current Capability - Low ESR handles motor running current without excessive heating, 4) Long Life - Expected 30,000-60,000 hours in motor applications, 5) Safety - Some models include internal protection (fuse action) for safety. Applications include: HVAC compressor motors, pump motors, fan motors, and general single-phase motor running. HJC motor run capacitors are available in standard and high-temperature versions. Always match the capacitor voltage rating to motor voltage with adequate margin (typically 1.5x motor voltage).

Use CBB61 series for motor run applications; match voltage rating to motor voltage with 1.5x margin.