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, convertoare de frecvenţă, UPS systems, inverter welders, and energy storage equipment.
Specificații cheie
Serie: CD138
Tensiune nominală: 400În DC
Nominal Capacitance: 7900μF
Tip: Screw-terminal, high-voltage large-capacity aluminum electrolytic capacitor
Aplicații tipice: 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 & Montare
Generally large cylindrical screw-terminal capacitors
Common diameters: φ77mm, φ85mm, etc.
Height range: 120mm ~ 160mm
Terminale: Top bolt terminals (M6 / M8)
CD138 400V 7900μF Condensator: Brand Models, Dimensiuni & Soluții de înlocuire
- Equivalent Models from Original and Mainstream Brands
| Marca | Model | Serie | Tip terminal | Lifetime |
| JiangHai | CD138 400V 7900μF | CD138 / CD138 PC | Screw‑terminal (M6/M8) | 5000–10000h at 85℃ |
| Nichicon | UUD1H791MCLD | UUD Series | Screw‑terminal | 2000h at 105℃ |
| Chemi‑Con (NCC) | E36D401CSN792MEH0M | E36D Series | Screw‑terminal | 5000h at 85℃ |
| EPCOS (TDK) | B43564‑S9798‑M1 | B43564 Series | Screw‑terminal | 5000h at 85℃ |
| Rubycon | ZLJ790000400P | ZLJ Series | Screw‑terminal | 5000h at 85℃ |
- Standard Dimensions
| Marca | Diameter (φ) | Înălţime | Terminal Spec | Note |
| JiangHai | 90mm | 105mm / 120mm | M6×2 | Common standard size |
| Nichicon | 90mm | 105mm | M6 | Import standard size |
| Chemi‑Con | 90mm | 110mm | M8 | High‑ripple current version |
| EPCOS | 85mm | 105mm | M6 | Design compact |
- 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)
| Replacement Capacitance | Modele recomandate | Motivul înlocuirii | Aplicație |
| 400V 6800μF | JiangHai CD138 400V 6800μF | Close capacitance (-13.9%), standard series, aprovizionare stabilă | Utilizare industrială generală, cost‑priority |
| Nichicon UUD1H681MCLD | |||
| EPCOS B43508‑A9687‑M000 | |||
| 400V 8200μF | JiangHai CD138 400V 8200μF | Close capacitance (+3.8%), standard series, performanță mai bună | Echipamente de precizie, high ripple current requirements |
| Nichicon UUD1H821MCLD | |||
| Chemi‑Con E36D401CSN822MEH0M |
- Compararea parametrilor cheie
| Parametru | CD138 400V 7900μF | 400V 6800μF | 400V 8200μF | Note |
| Nominal Capacitance | 7900μF | 6800μF | 8200μF | Tolerance typically ±20% |
| Tensiune nominală | 400În DC | 400În DC | 400În DC | Recommended operating voltage ≤ 320V (80% derating) |
| Ripple Current | Aproximativ. 20O (120Hz, 85℃) | Aproximativ. 18O | Aproximativ. 22O | Higher capacitance supports higher ripple current |
| ESR (Equivalent Series Resistance) | Aproximativ. 15mΩ | Aproximativ. 17mΩ | Aproximativ. 14mΩ | Lower ESR provides better filtering |
| Durata de viață | 5000–10000h at 85℃ | Same | Same | Lifetime roughly doubles for every 10℃ temperature reduction |
- Selection and Replacement Recommendations
- Exact Match
Prioritize the original model with identical specifications to ensure full performance consistency, suitable for precision equipment repair or original replacement.
- 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.
- Înlocuire de marcă
Recommended domestic brands: JiangHai, Aishi, CapXon-high cost-performance, aprovizionare stabilă.
Recommended imported brands: Nichicon, Chemi-Con, Rubycon-reliable quality, various long-life versions available.
- Note de instalare
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 Condensator: 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 (cost mai mic)
- Core Performance Comparison
| Parametru | JiangHai | Nichicon | Chemi‑Con (NCC) | EPCOS (TDK) | Rubycon |
| CD138 400V 7900μF | UUD1H791MCLD | E36D401CSN792MEH0M | B43564‑S9798‑M1 | ZLJ790000400P | |
| Nominal Capacitance | 7900μF (±20%) | 7900μF (±20%) | 7900μF (±20%) | 7900μF (±20%) | 7900μF (±20%) |
| Tensiune nominală | 400În DC | 400În DC | 400În DC | 400În DC | 400În DC |
| Ripple Current | Aproximativ. 20O (120Hz, 85℃) | Aproximativ. 23O (120Hz, 85℃) | Aproximativ. 24O (120Hz, 85℃) | Aproximativ. 22O (120Hz, 85℃) | Aproximativ. 21O (120Hz, 85℃) |
| ESR | Aproximativ. 15–18mΩ (120Hz, 85℃) | Aproximativ. 12–14mΩ | Aproximativ. 11–13mΩ | Aproximativ. 13–15mΩ | Aproximativ. 14–16mΩ |
| Lifetime | 5000–10000h at 85℃ | 2000h at 105℃ | 5000h at 85℃ | 5000h at 85℃ | 5000h at 85℃ |
| 2000h at 105℃ | 8000h at 85℃ | 2000h at 105℃ | 2000h at 105℃ | 2000h at 105℃ | |
| Dimensiuni | φ90mm × 105/120mm | φ90mm × 105mm | φ90mm × 110mm | φ85mm × 105mm | φ90mm × 105mm |
| M6×2 terminals | M6 terminals | M8 terminals | M6 terminals | M6 terminals | |
| Curent de scurgere | ≤0.79mA (20℃, 400V, 2min) | ≤0.79mA | ≤0.79mA | ≤0.79mA | ≤0.79mA |
| Operating Temp | -40℃ to +85℃ (standard) | -40℃ to +105℃ | -40℃ to +105℃ | -40℃ to +105℃ | -40℃ to +105℃ |
| -40℃ to +105℃ (high‑temp) | |||||
| Gama de prețuri | Aproximativ. ¥80–120 | Aproximativ. ¥200–280 | Aproximativ. ¥220–300 | Aproximativ. ¥180–250 | Aproximativ. ¥190–260 |
- Performance Characteristics by Brand
2.1 JiangHai-Representative Domestic Brand
Avantaje:
Extremely cost-effective, priced at only 1/2 la 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.
Caracteristici tehnice: 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
Avantaje:
Strong ripple current capability, aproximativ. 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.
Caracteristici tehnice: 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
Avantaje:
Highest ripple current capability, aproximativ. 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.
Caracteristici tehnice: The E36D series uses reinforced electrode structure and unique electrolyte formula, potrivit pentru medii dure.
2.4 EPCOS (TDK)-Representative European Brand
Avantaje:
Compact design with only 85mm diameter, economisind spațiu de instalare.
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.
Caracteristici tehnice: 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
Avantaje:
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.
Caracteristici tehnice: Uses high-purity electrolyte and special sealing technology for long service life, suitable for frequently started/stopped equipment.
- Impact of Performance Differences on Applications
| Aplicație | Impact of Performance Variations | Recommended Brand |
| Precision Equipment Repair / OEM Replacement | Strict parameter matching required to avoid performance drift | Original model first, then Chemi‑Con / Nichicon |
| General Industrial VFD / UPS | Ripple current and ESR differences have minor effect; standard replacement acceptable | JiangHai (cost) or EPCOS (dimensiune) |
| High‑Frequency SMPS / Inverter Welder | High ripple current demand; lower ESR preferred to reduce heat | Chemi‑Con > Nichicon > EPCOS |
| Long‑Life Equipment (>5 years continuous operation) | Significant lifetime difference; lifetime doubles per 10℃ cooler | JiangHai (high‑temp), Nichicon, Chemi‑Con |
| Cost‑Sensitive Projects | Large price gap; domestic brands greatly reduce cost | JiangHai |
- 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
| Replacement Capacitance | Modele recomandate | Performance Change | Aplicație |
| 400V 8200μF | JiangHai CD138 400V 8200μF | +3.8% C, +10% ripple, -7% ESR | Optimal replacement, better filtering and ripple handling |
| Nichicon UUD1H821MCLD | |||
| Chemi‑Con E36D401CSN822MEH0M | |||
| 400V 6800μF | JiangHai CD138 400V 6800μF | -13.9% C, -10% ripple, +13% ESR | Economical replacement with acceptable performance |
| Nichicon UUD1H681MCLD | |||
| EPCOS B43508‑A9687‑M000 |
4.3 Instrucțiuni de instalare și utilizare
- Derating: Recommended operating voltage ≤ 320V (80% derating) to extend lifetime.
- Thermal Design: Maintain ≥10mm clearance for heat dissipation; lifetime doubles per 10℃ reduction.
- Correct Polarity: Can = negative, top bolt = positive; reverse installation causes failure.
- Controlul cuplului: Tighten bolt terminals to 5-8N·m to avoid loose connections or damage.
- Concluzie
CD138 400V 7900μF capacitors from different brands show clear differences in ripple current, ESR, lifetime, si pret:
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.
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