CD138 400V 7900μF Capacitor

CD138 is a Chinese national standard designation, representing a large-capacity screw-terminal aluminum electrolytic capacitor, widely used in industrial applications such as high-power power supplies, frequency converters, UPS systems, inverter welders, and energy storage equipment.

Key Specifications

Series: CD138

Rated Voltage: 400V DC

Nominal Capacitance: 7900μF

Type: Screw-terminal, high-voltage large-capacity aluminum electrolytic capacitor

Typical Applications: DC bus filtering, energy storage, high-power switching power supplies, DC link of frequency converters

Common Equivalent / Replacement Ratings

This capacitance is not a standard commonly used value. Common engineering replacement / equivalent models:

400V 6800μF, 400V 8200μF (closest standard capacitances)

Standard values in the same series: 400V 4700μF / 5600μF / 6800μF / 8200μF / 10000μF

Outline & Mounting

Generally large cylindrical screw-terminal capacitors

Common diameters: φ77mm, φ85mm, etc.

Height range: 120mm ~ 160mm

Terminals: Top bolt terminals (M6 / M8)

CD138 400V 7900μF Capacitor: Brand Models, Dimensions & Replacement Solutions

1. Equivalent Models from Original and Mainstream Brands

2. Standard Dimensions

3. Direct Replacement Solutions

3.1 Exact Match (Same Capacitance)

JiangHai CD138 400V 7900μF (direct original replacement)

Nichicon UUD1H791MCLD 400V 7900μF

Chemi-Con E36D401CSN792MEH0M 400V 7900μF

EPCOS B43564-S9798-M1 400V 7900μF

3.2 Standard Capacitance Replacements (Common in Engineering)

4. Key Parameter Comparison

5. Selection and Replacement Recommendations
6. Exact Match

Prioritize the original model with identical specifications to ensure full performance consistency, suitable for precision equipment repair or original replacement.

2. Standard Capacitance Replacement

For general industrial frequency converters, UPS, etc., 400V 8200μF is the best choice: slightly larger capacitance, better filtering, and higher ripple current capability.

For cost or inventory control, 400V 6800μF can be used as an economical alternative with acceptable performance differences.

3. Brand Replacement

Recommended domestic brands: JiangHai, Aishi, CapXon-high cost-performance, stable supply.

Recommended imported brands: Nichicon, Chemi-Con, Rubycon-reliable quality, various long-life versions available.

4. Installation Notes

Bolt terminals must be properly tightened (torque 5-8N·m) to avoid poor contact.

Polarity must be correct: can is negative, top bolt is positive.

Keep installation clearance ≥10mm for sufficient heat dissipation.

CD138 400V 7900μF Capacitor: Performance Differences Among Brands

Key Summary

Imported brands (Nichicon, Chemi-Con, EPCOS, Rubycon) generally outperform domestic brands in ripple current, ESR consistency, and long-term durability, but at a higher price.

Domestic brand (JiangHai) excels in cost-performance and supply stability, with basic performance meeting industrial standards.

For replacement, prioritize 400V 8200μF (slightly larger capacitance, better filtering), followed by 400V 6800μF (lower cost)

1. Core Performance Comparison

2. Performance Characteristics by Brand

2.1 JiangHai-Representative Domestic Brand

Advantages:

Extremely cost-effective, priced at only 1/2 to 1/3 of imported brands.

Designed specifically for industrial scenarios, compatible with frequency converters, UPS, inverter welders, etc.

High capacitance retention rate, with capacitance decay <5% over service life.

Stable supply, sufficient domestic inventory, short lead times.

Technical Features: Uses high-purity aluminum foil and high-quality electrolyte; the CD138 series is JiangHai’s flagship screw-terminal capacitor with performance close to international levels.

2.2 Nichicon-One of the Top Three Japanese Brands

Advantages:

Strong ripple current capability, approx. 15% higher than domestic brands.

Lower ESR for better filtering, suitable for high-precision power systems.

2000h lifetime at 105℃, excellent temperature adaptability.

Outstanding consistency, minimal performance variation between batches.

Technical Features: The UUD series adopts advanced electrode foil treatment and stable electrolyte, ideal for long-term high-load operation.

2.3 Chemi-Con (NCC)-Specialist in High-Voltage Large Capacitors

Advantages:

Highest ripple current capability, approx. 20% higher than domestic brands.

Lowest ESR, low power loss, excellent heat dissipation.

High-reliability design, strong vibration and shock resistance.

Full in-house production from aluminum foil to finished product, ensuring quality control.

Technical Features: The E36D series uses reinforced electrode structure and unique electrolyte formula, suitable for harsh environments.

2.4 EPCOS (TDK)-Representative European Brand

Advantages:

Compact design with only 85mm diameter, saving installation space.

Balanced ripple current and ESR, ideal for size-constrained equipment.

Compliant with European industrial standards, compatible with Siemens, ABB, etc.

Strong anti-EMI performance for complex industrial environments.

Technical Features: The B43564 series uses special foil processing with low ESL (Equivalent Series Inductance) and good high-frequency performance.

2.5 Rubycon-Pioneer in Electrolytic Capacitors

Advantages:

Low-impedance design; ZLJ series developed specifically for high-power power supplies.

Low leakage current, low power loss during long-term standby.

Stable temperature coefficient, small performance fluctuation over wide temperature range.

Large global market share, comprehensive after-sales service network.

Technical Features: Uses high-purity electrolyte and special sealing technology for long service life, suitable for frequently started/stopped equipment.

3. Impact of Performance Differences on Applications

4. Selection and Replacement Recommendations

4.1 Exact Match Selection

Prioritize identical original models for full performance consistency.

JiangHai CD138 400V 7900μF is the best domestic choice with top cost-performance.

Among imports, Chemi-Con E36D series is preferred for best ripple current and ESR.

4.2 Recommended Standard Capacitance Replacements

4.3 Installation and Usage Guidelines

1. Derating: Recommended operating voltage ≤ 320V (80% derating) to extend lifetime.
2. Thermal Design: Maintain ≥10mm clearance for heat dissipation; lifetime doubles per 10℃ reduction.
3. Correct Polarity: Can = negative, top bolt = positive; reverse installation causes failure.
4. Torque Control: Tighten bolt terminals to 5-8N·m to avoid loose connections or damage.
5. Conclusion

CD138 400V 7900μF capacitors from different brands show clear differences in ripple current, ESR, lifetime, and price:

Imported brands (Chemi-Con, Nichicon, etc.) lead in high-performance parameters but are more expensive.

Domestic brand (JiangHai) leads in cost-performance and supply stability, with basic performance sufficient for industrial applications.