Precision Power Conversion
Featured Power Conversion & Transformer Solutions
Directly supplied by Shaanxi Zelqo Power Co., Ltd. for Korean industrial control boards, smart energy systems, and high-density PCB equipment.
Fullstar 5V Power Supply 2A Power Adapter US Plug 5.5*2.1mm Ferrite Core
9V 2A Adapter Power Supply AC DC 5V 9V 12V 15V 24V 1A-10A Regulated
Variable Voltage Power Supply 240W AC 110V/220V to DC 12V/24V Industrial
12V 50A 600W Adjustable DC Power Supply AC 110V/220V with CE Driver
Custom 12V-50V 0-1200VDC 1500W High Precision Switching Power Supply
100W 14.6V 5A UPS Battery Charger Switching Mode Power Supply AC-DC
OEM ODM Desktop Power Supply Adapter UK Plug for Smart Gateway IoT Hub
Executive Technical Whitepaper
Anatomy of Vacuum Encapsulated Transformers for Harsh Industrial Environments
As South Korea's industrial landscape accelerates towards advanced smart factory architectures, electric vehicle (EV) charging micro-grids, and AIoT edge computing, electronic design engineers face stringent demands for galvanic isolation, thermal resilience, and ultra-compact board footprints. Mini encapsulated transformers represent the gold standard in board-level magnetic components, bridging the gap between raw AC grid volatility and sensitive DC low-voltage microcontrollers.
Unlike conventional open-frame or varnished EI transformers, mini encapsulated transformers are housed in flame-retardant thermoplastic cases (UL94-V0 rated) and permanently cast under high-vacuum pressure with high-dielectric epoxy resin. This complete hermetic sealing eliminates atmospheric moisture ingress, ambient particulate contamination, chemical vapor oxidation, and microphonic mechanical hum. In the South Korean power distribution network—characterized by nominal 220V single-phase / 380V three-phase at 60Hz—these encapsulated components provide unmatched dielectric withstand capabilities (exceeding 4,200Vrms primary-to-secondary isolation) and withstand extreme thermal cycling from -25°C to +70°C ambient operating temperatures (Class B / Class F thermal insulation).
4,200V
Dielectric Isolation Hi-Pot
0.35W
Ultra-Low No-Load Loss
UL94-V0
Flame Retardant Potted Resin
100%
Automated Multi-Stage Tested
Reinforced Galvanic Isolation
Engineered with dual-chamber bobbins separating primary and secondary copper windings. Creepage and clearance distances exceed 8.0mm, comfortably surpassing IEC/KC 61558-2-6 safety standards for safety isolating transformers.
Optimized 60Hz Magnetic Flux
Custom grain-oriented or non-oriented high-silicon electrical steel lamination stacks specifically calculated for 60Hz flux density (avoiding high core losses and core saturation typical of under-engineered 50Hz components imported into Korea).
Inherently Short-Circuit Proof
Available in both inherently safe designs (engineered winding impedance limits maximum current under continuous dead-short faults without exceeding critical thermal runaway) and non-inherently safe versions with integrated internal PTC thermistors.
Standardized Engineering Families
Precision Potted PCB Transformer Parameter Matrix
Direct drop-in replacements for standard European (Hahn, Myrra, Block) and Korean industrial pinout configurations.
| Series Core | Rated Power (VA) | Nominal Input (VAC) | Standard Secondaries (V / mA) | Dimensions (L × W × H mm) | No-Load Loss | Short-Circuit Protection | Mounting Type |
|---|---|---|---|---|---|---|---|
| EI 30/10.5 | 0.35 VA – 0.6 VA | 220V / 230V 60Hz | 6V, 9V, 12V, 15V, 24V, Dual 12V | 32.5 × 27.5 × 15.2 | < 0.15 W | Inherently Safe | PCB Through-Hole |
| EI 30/12.5 | 0.8 VA – 1.5 VA | 220V / 230V 60Hz | 9V (166mA), 12V (125mA), 24V (62mA) | 32.5 × 27.5 × 22.0 | < 0.20 W | Inherently Safe | PCB Through-Hole |
| EI 30/15.5 | 1.5 VA – 2.0 VA | 220V 60Hz | 6V, 9V, 12V, 18V, 24V, 2×12V | 32.5 × 27.5 × 24.5 | < 0.25 W | Inherently Safe | PCB Through-Hole |
| EI 30/18.0 | 2.1 VA – 2.8 VA | 220V 60Hz | 9V (266mA), 12V (200mA), 24V (100mA) | 32.5 × 27.5 × 27.0 | < 0.30 W | Inherently Safe | PCB Through-Hole |
| EI 38/13.6 | 3.2 VA – 4.5 VA | 220V / 380V 60Hz | 12V (375mA), 24V (187mA), 2×15V | 41.0 × 35.0 × 28.0 | < 0.40 W | External / PTC | PCB Pin Mount |
| EI 48/16.8 | 6.0 VA – 10.0 VA | 220V / 380V 60Hz | 12V (833mA), 24V (416mA) | 50.5 × 42.5 × 34.5 | < 0.55 W | Thermal Cutoff Fuse | PCB Pin Mount |
| UI 30/10.5 Low Profile | 3.0 VA – 6.0 VA | Dual 110V / 220V 60Hz | Dual 6V, 9V, 12V, 15V, 18V | 53.0 × 44.0 × 19.5 | < 0.35 W | Non-Inherently Safe | Ultra-Slim 1U PCB |
Target Market Penetration
Critical Deployment Scenarios Across Korea's Core Industries
Precision magnetic coupling tailored to South Korea's high-tech manufacturing, municipal automation, and smart home ecosystems.
KEPCO Smart Metering (K-AMI)
Korea Electric Power Corporation (KEPCO) mandates 15+ year operational lifespans for Advanced Metering Infrastructure. Our EI30 encapsulated transformers isolate micro-inverters and sub-metering telemetry boards against harsh grid transient surges and high lightning strike incidence in rural mountainous substations.
EV Slow & Fast Charger Control (E-Mobility)
Integrated into primary auxiliary power supplies within Korean residential wallbox EV chargers and commercial DC fast-charging stations. The vacuum-potted structure shields sensitive gate-drive and OCPP communication boards from dust, water washdown, and conductive salt mist in coastal regions.
Gumi & Ulsan Industrial Automation (PLC)
Heavy machinery, servo-drives, and robotic assembly lines generate intense EMI/RFI noise and vibration. Encapsulated transformers resist mechanical harmonic shock up to 5G while maintaining stable reference rails for analog sensing circuits and optical isolated relays.
Smart Apartment Home Automation & HVAC
Korea's tier-1 residential builders demand zero-hum acoustics in wall-mounted touch panels, boiler controllers, and heat pumps. Our potted transformers guarantee silent acoustic operation (<20dB) and comply with strict standby power consumption targets (<0.2W).
Regulatory Compliance Whitepaper
Navigating Korean Safety Norms: KC Certification & Technical Adaptation
Exporting magnetic sub-assemblies or finished equipment into South Korea requires uncompromising adherence to local technical standards overseen by the Korean Agency for Technology and Standards (KATS). Sourcing teams cannot simply repurpose standard European or North American inventory without confronting electrical mismatch issues.
KC 61558-1 / 61558-2-6 Harmonization
Korea's Safety Confirmation Scheme categorizes transformers intended for electrical appliances and IT systems under KC 61558. Our components are manufactured with certified Class B (130°C) wire, UL-recognized epoxy potting, and dual insulation barriers, facilitating swift CB scheme transfer to local certification bodies like KTL, KTR, and KTC.
220V 60Hz vs. 50Hz Thermal Derating
Operating an unmodified 50Hz transformer on Korea's 60Hz grid actually reduces flux density, but reverse engineering without recalculating turns creates parasitic reactive loss and poor line regulation. Zelqo Power optimizes core volume specifically for 60Hz, achieving a 12% smaller footprint and lower thermal rise for the same VA rating.
Korean Standby Power Standards
Under the 'Standby Korea 2010' roadmap and mandatory Energy Efficiency Labeling Scheme, smart appliances must restrict quiescent no-load consumption. Our ultra-efficient EI30/10.5 series features optimized primary turn counts and specialized steel silicon grades to cut idle losses below 0.15W.
Intertek-Verified On-Site Audited Facility
Manufacturing Excellence
Why Korean OEMs Trust Shaanxi Zelqo Power Co., Ltd.
Headquartered in Xi'an, Shaanxi, China, Shaanxi Zelqo Power is an industry-recognized custom designer and high-volume manufacturer of precision magnetic components, toroidal transformers, and switching power assemblies. We combine rapid prototyping engineering with multi-stage automated production lines to satisfy the most demanding Korean B2B procurement benchmarks.
- 25+ Automated Process & QC Stations: Featuring automated CNC multi-spindle coil winders, robotic wire strippers, and continuous-feed vacuum casting ovens that eliminate air pockets within potting resin.
- 100% Comprehensive Dielectric Testing: Every individual transformer passes automated LCR bridge inductance testing, winding DC resistance, inter-turn surge impulse, and 4.2kV hi-pot breakdown screening before packaging.
- Direct China-Korea Free Trade Agreement (FTA) Logistics: Form E documentation ensuring preferential import customs tariff rates for Korean enterprises, with rapid air-courier sample transit to Incheon within 3-4 days.
- Custom Tooling & Pin Configurations: Full engineering flexibility to adapt pin layout spacing, secondary tap voltages, and case profiles to seamlessly drop into pre-existing Korean PCB master layouts.
Procurement Knowledgebase
Frequently Asked Questions by Korean Sourcing Teams
Direct answers covering import regulations, testing certificates, electrical parameters, and logistics.
1. What is the standard HS code and tariff rate for importing encapsulated transformers into South Korea? +
Mini encapsulated PCB transformers are typically classified under HS Code 8504.31.1000 (Transformers having a power handling capacity not exceeding 1 kVA, electronic types). Under the China-South Korea Free Trade Agreement (CK FTA), shipments accompanied by an official Certificate of Origin (Form FTA) benefit from reduced or zero preferential import tariff rates, lowering landed procurement costs compared to sourcing from European distributors.
2. How do you assist Korean customers in obtaining KC Safety Certification? +
While component transformers mounted directly onto a PCB often fall under the final equipment's safety evaluation, high-voltage isolating units may require certification under KC 61558-1 / 61558-2-6. Zelqo Power builds to international IEC 61558 standards and provides complete CB Scheme test reports, raw material component lists (CDF), UL flame-retardant certificates for potting resins (UL94-V0), and full dielectric breakdown records, allowing Korean test laboratories (such as KTL, KTR, or KTC) to execute rapid document-based transfer.
3. Why is 60Hz magnetic design critical for the Korean electrical grid? +
South Korea operates on a single-phase 220V, 60Hz grid. Many off-the-shelf transformers produced in Europe or Japan are originally calculated for 50Hz networks. Operating a 50Hz transformer at 60Hz decreases core flux density by approximately 17%, which generally prevents saturation, but results in an unnecessarily large, heavy, and costly magnetic core. Zelqo Power engineers custom 60Hz transformer cores with optimized turn ratios and silicon steel cross-sections, saving weight and board surface area while minimizing idle core wattage.
4. What is the difference between "inherently" and "non-inherently" short-circuit proof potted transformers? +
An inherently short-circuit proof transformer (common in models under 3VA, such as EI30/10.5 and EI30/12.5) relies on high internal coil resistance and magnetic leakage inductance to naturally choke the short-circuit current. Even if secondary pins are permanently bridged, internal temperatures remain within the thermal insulation class limit without fire hazard. A non-inherently short-circuit proof transformer (typically 3.2VA and above) requires external protection or integrates a one-shot thermal fuse or self-resetting PTC thermistor into the winding stack.
5. Can Zelqo Power replicate pin configurations from European brands like Hahn or Myrra? +
Yes. Most of our encapsulated EI30, EI38, and EI48 tooling follows standardized international pin grids (e.g., 5mm pitch, dual-pin primary on pins 1-5, secondary outputs on pins 7-9). We offer direct 1:1 drop-in electrical and mechanical replacements for popular Hahn (BV20, BV30 series) and Myrra (44000 series) parts, allowing Korean engineers to replace costly legacy supply chains without modifying their PCB gerber files.
6. What quality assurance and life-testing steps are conducted before export shipping? +
Every production lot undergoes 100% automated electrical testing using multi-channel digital test benches. Measurements include no-load voltage verification, full-load voltage drop, magnetizing current, DC winding resistance, impulse surge testing (checking for micro-fissures in magnet wire enamel), and primary-to-secondary hi-pot testing at 4,200V AC for 60 seconds (or 4,800V for 1 second in high-speed inline testing). Statistical batch samples undergo thermal shock and vacuum leakage testing.
7. What are the typical lead times for engineering prototypes and mass production to Korea? +
Custom engineering prototype samples can typically be fabricated and bench-tested within 5 to 7 working days. International express transit (via DHL, FedEx, or SF Express) from our Xi'an manufacturing plant to Seoul, Incheon, or Busan takes 2 to 3 days. For volume orders, standard mass-production cycles range between 18 and 25 calendar days, supported by flexible sea freight (Weihai/Qingdao to Incheon ferry transit in under 24 hours).
8. Do you support RoHS, REACH, and environmental halogen-free requirements? +
Absolutely. In accordance with South Korea's Act on Resource Circulation of Electrical and Electronic Equipment and Vehicles (Korea RoHS), all raw materials—including copper magnet wire, bobbins, epoxy encapsulation resin, core silicon steel, and solder alloys—are certified lead-free, halogen-free, and fully compliant with EU RoHS 2.0 (Directive 2011/65/EU and 2015/863) and REACH SVHC regulations. Complete third-party SGS/CTI lab test reports are available upon request.
Accelerate Your Sourcing with Verified Magnetic Engineering
Whether you need an exact drop-in replacement for an existing PCB footprint or a custom multi-tap 220V 60Hz encapsulated transformer for an upcoming Korean product launch, our technical sales engineers in Xi'an are ready to support your design review.
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