EI3018 Encapsulated Transformer
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EI3018 Encapsulated Transformer

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Product Details
Performance
Features
Applications

EI3018 Encapsulated Transformer

I.External Dimensions (unit: millimeters)

EI3018尺寸图.jpg


II. Electrical Schematic Diagram

EI3018.jpg

III. Electrical Parameters


Primary voltage

(V)

Secondary voltage(V)

Current

(mA)

Connect pin

Open circuit voltage

230

24

95

1-5 / 7-9

4000 V


IV.Electrical Strength


NO.

ITEM

TERMINAL

REQUEST

1

WITHSTAND

VOLTAGE

Primary-Secondary

4000V AC   10mA   21s


V.Bill of Materials

No.

Name

Specification

Type

Thickness Flame

1

Silicon steel sheet

DW470A
thickness:0.5mm

EI30

\

2

Bobbin

PBT

EI30*18

UL-94V

3

Shell

PBT

EI30*18

UL-94V

4

Enameled wire

Polyurethane enameled wire

2UEW-F

≥155°C

5

Insulating tape

Flame-retardant polyester

insulating tape

CT* (c)(g)

130°C

6

Potting compound

Epoxy resin

TX5090A/114-9B

\


         EI Encapsulated Transformer Series Power and Dimension Table

Model

Core type

Output power (W)

Size

L*W*H

Note

STEE20-001

EE20/6

0.35

23.5*22.5*17.8


STEE20-002

EE20/10

0.4-0.5

23.5*22.5*21.5


STEI30-001

EI30/5

0.5

33*27.8*16


STEI30-002

EI30/8

0.8

33*27.8*19


STEI30-003

EI30/10.5

1-1.5

32*27.8*22


STEI30-004

EI30/12.5

1.5-1.8

33*27.8*25


STEI30-005

EI30/15.5

1.8-2.3

33*27.8*28


STEI30-006

EI30/18

1.9-2.95

33*27.8*30


STEI30-007

EI30/23

2.8-3

33*27.8*35


STEI38-001

EI38/7.5


41.5*35*22.5


STEI38-002

EI38/13.6

3-4.5

41.5*35*28.5


STEI42-001

EI42/14

4.6-6

45*39*32.8


STEI42-002

EI42/20

8.1-10

45*39*37.8


STEI48-001

EI48/16

10.1-12

51*43*34


STEI48-002

EI48/20

12.1-14

51*43*39


STEI54-001

EI54/18

15.1-18

57*49*42


STEI60-001

EI60/30

20.1-30

64*54*57



*Specifications and parameters can be customized according to customer design requirements.

EI Potting Transformer is an EI-type low-frequency transformer vacuum-potted with epoxy resin. Its core advantages include insulation and moisture resistance, interference suppression and flame retardancy, and robust structure. It is suitable for low-power PCB through-hole applications, offering protection up to IP67. Typical power ratings range from 5VA to 100VA, with insulation class mostly B (130°C). It serves as a high-reliability power isolation solution for industrial control, instrumentation, and other fields.
I. Core Performance Parameters and Analysis

Parameter

Category

Key Indicators

Performance Analysis

Electrical

Performance

Rated Power: 5VA-100VA

Suitable for low-power supply, high voltage accuracy, meets global grid fluctuation requirements, compatible with most industrial and civilian equipment.

Input Voltage: AC110V/220V/380V ±10%

Output Voltage: AC12V/24V/36V ±2%

Frequency: 50/60Hz (45-60Hz Universal)

Insulation

& Safety

Dielectric Strength: 3750V-4200Vrms/1min

Potting resin enhances insulation and withstand voltage, eliminates leakage/short circuit risk, suitable for high-temperature conditions, complies with UL/EN/CQC safety standards.

Insulation Resistance: ≥1000MΩ

Insulation Class: B Class (130°C)

Protection &

Environment

Protection Rating: IP67

Fully sealed against dust/water, stable in outdoor/humid environments; flame-retardant materials suppress fire, wide temperature range adapts to industrial extremes.

Flame Retardant Rating: UL94-V0

Operating Temperature: -40°C ~ +70°C

Mechanical &

Electromagnetic

Construction: Cold-rolled silicon steel sheets

+ copper enameled wire + isolated bobbin

Vacuum potting and curing ensure solid structure, resistant to shock/vibration; isolated windings and silicon steel sheets optimize leakage flux, reducing EMI interference.

Leakage Flux: Low

Shock/Vibration Resistance: High

Efficiency &

Thermal

Efficiency: Approx. 90%-95%

Compact winding and potting enable balanced heat dissipation, low loss saves energy, extends device lifespan, suitable for long-term continuous operation.

Temperature Rise: ~25% lower than traditional transformers


II. Core Performance Advantages and Principles

  • Insulation & Moisture Resistance: Epoxy resin vacuum potting fills gaps between coils and housing, forming a dense insulating layer with IP67 protection. This solves insulation failure issues in humid, salt spray environments, suitable for outdoor/underwater equipment.


  • Interference Suppression & Stability: Isolated bobbin and silicon steel sheet lamination design reduces leakage flux. Potting material absorbs vibration and noise, suppresses EMI, improving signal and power supply stability, suitable for precision instruments and control systems.


  • Safety & Durability: UL94-V0 flame-retardant housing + potting resin enables quick self-extinguishing during overcurrent/short circuit. Internal thermal protectors (optional) cut off power during overload, preventing equipment burnout. Service life can exceed 20,000 hours.


  • Structure & Installation: Pin-through-hole (PTH) mounting on PCB, compact size, low profile, suitable for automated soldering and mass production, reducing assembly costs and improving device integration.


III. Performance Limitations and Optimization Directions

  • Power Upper Limit: Limited by EI core and potting heat dissipation, power rating is difficult to exceed 100VA. For high-power applications, consider toroidal or EE series potted transformers.


  • Heat Dissipation Constraint: Fully sealed structure relies on housing conduction for heat dissipation. Load rate should be controlled (recommended ≤80%). For high-temperature conditions, add heat sinks or derate usage.


  • Customization Cost: Special voltage/power requirements need adjustments to winding and potting molds, leading to higher costs for small-batch customization. Best suited for standardized, high-volume applications.


IV. Typical Application Scenarios

  • Industrial Control: Isolation power supply for PLCs, inverters, sensors, etc., suitable for factory humid and EMI environments.


  • Instrumentation: Electricity meters, temperature controllers, medical devices, etc., where high-precision power supply and insulation safety meet metrology/medical standards.


  • Lighting & Household Appliances: LED drivers, smart home controllers, where IP67 protection suits outdoor/bathroom and other humid scenarios.


  • Communication & Security: Surveillance cameras, access control systems, where wide temperature range and interference resistance ensure stable operation in outdoor/harsh environments.


V. Selection and Usage Recommendations

  • Selection Points: Match model based on load power (leave 20% margin), input/output voltage, insulation class, and protection requirements. Prioritize products certified by UL/EN/CQC to ensure compliance.


  • Usage Notes: Avoid overload and frequent switching to prevent excessive temperature rise. For outdoor installation, secure firmly to avoid mechanical damage. Regularly inspect pin soldering and housing sealing to ensure long-term stability.


EI Potted Transformer features center around four key dimensions: full-sealed protection, high insulation safety, low interference and stability, and easy integration. It is suitable for low-power isolation power supply requirements in harsh operating conditions. Specific characteristics are as follows:
Excellent Insulation & Moisture Resistance, High Protection Rating
Utilizing an epoxy resin vacuum potting process, gaps between the coil, core, and housing are completely filled, forming a dense insulating layer with a protection rating up to IP67. It can withstand harsh environments like moisture, salt spray, and dust, eliminating risks of insulation failure or short circuits caused by dampness.
High Electrical Safety, Strong Compliance
Features high dielectric strength (3750V-4200Vrms/1min), insulation resistance ≥1000MΩ, and typically B class (130°C) insulation rating. The potting material meets the UL94-V0 flame retardant standard, enabling self-extinguishing during overcurrent or short circuits to reduce fire hazard. Complies with safety certification requirements from multiple countries/regions such as UL, EN, and CQC.
Low Noise & Interference, Stable Operation
A split bobbin design paired with EI-type cold-rolled silicon steel sheets effectively reduces leakage flux and minimizes electromagnetic interference (EMI). The potting resin absorbs core vibrations, resulting in significantly lower operational noise compared to traditional non-potted transformers. Suitable for precision instruments, industrial control systems, and other scenarios with high electromagnetic compatibility requirements.
Robust Structure, Vibration and Shock Resistant
After potting and curing, internal components are securely locked, resulting in high overall mechanical strength and excellent resistance to vibration and shock. Can withstand the mechanical stresses from frequent start-stop cycles in industrial equipment or outdoor installation, with a service life exceeding 20,000 hours.
Easy Integration, Suitable for Automated Assembly
Features a pin-type through-hole design for direct soldering onto PCB boards. Its low profile and compact volume are compatible with automated production line batch soldering, reducing device integration and assembly costs. Ideal for products like miniaturized instruments and smart home controllers.
Excellent Efficiency, Controllable Temperature Rise
The winding employs a tightly wound process with low copper loss, achieving overall efficiency of 90%-95%. The potting material provides balanced thermal conductivity, offering better heat dissipation than open-type transformers, with a temperature rise approximately 25% lower than traditional products. Suitable for long-term continuous load operation.
Power Limitation, Suitable for Low-Power Scenarios
Limited by EI core specifications and potting heat dissipation, the rated power typically ranges from 5VA to 100VA. For high-power applications, consider switching to toroidal or EE series potted transformers.
EI Potted Transformer, leveraging its core strengths of high insulation protection, low electromagnetic interference, and robust structure, is primarily suited for low-power isolation power supply applications in harsh operating conditions with stringent safety and stability requirements. Typical application areas and specific equipment are as follows:
Industrial Control Field
Serves as an isolation power supply for PLCs, inverters, servo drives, and sensors. It can withstand the humid, dusty, and EMI-intensive environments of factory workshops, ensuring stable control signals and power supply to prevent equipment malfunctions caused by insulation failure or interference.
Instrumentation Field
Used in electricity meters, temperature controllers, pressure transmitters, laboratory analyzers, etc. Its characteristics of high-precision voltage output and high dielectric strength meet the accuracy requirements of metering equipment, while also complying with safety insulation standards for medical instruments and testing devices.
Smart Home and Lighting Field
Suitable for LED drivers, smart door locks, thermostat panels, security cameras, etc. The IP67 protection rating handles humid environments such as bathrooms and outdoors, while its compact through-hole design meets the miniaturization and integration needs of smart home products.
Security and Communication Field
Applied in outdoor or field equipment like surveillance cameras, access control systems, and small communication base stations. Its wide operating temperature range (-40℃~+70℃) and shock/vibration-resistant properties ensure long-term stable operation in extreme environments.
Medical Equipment Field
Used in small portable medical devices (e.g., blood glucose meters, blood pressure monitors, portable monitors). The high insulation performance prevents electric leakage that could harm users, while its low electromagnetic interference ensures it does not affect the measurement accuracy of the instruments.
Rail Transit and Marine Field
Suitable for small onboard control equipment in rail transit and auxiliary instruments within ship cabins. It can withstand special conditions like vibration and salt spray corrosion, meeting the high-reliability requirements of maritime and rail transit equipment.
Tianjin Sitong Electronic Co., Ltd
+86  022-58333948         +86  15202280664
admin@e-sitong.com
Add：12-2-501, Research & Innovation IndustrialPark, LDUV, Shuanggang Jinnan District, Tianjin, China 300350