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We offer a comprehensive portfolio including resistors, braking units, reactors, power filters, and transformers, with full customization options to meet diverse application requirements.
The Electromagnetic Interference Filter incorporates a multi-stage low-pass filtering network consisting of a common-mode choke, X capacitors, Y capacitors, and resistors.
The common-mode choke uses two conductors wound on the same magnetic core and presents high impedance to common-mode interference. X capacitors are connected across the line conductors to suppress differential-mode interference, while Y capacitors are connected between the power lines and ground to provide a path for high-frequency common-mode noise to ground.
These components work together to provide broadband EMI suppression. The multi-stage filtering structure is optimized according to the interference frequency characteristics commonly encountered in variable frequency drive applications.
| Parameter | Specification |
|---|---|
| Rated Voltage | 220VAC / 380VAC / 690VAC / 1140VAC |
| Operating Frequency | 50Hz / 60Hz / up to 500Hz |
| Rated Current | 5A--1600A |
| Dielectric Strength | Line-to-Line: 1500VDC, 60s; Line-to-Ground: 2500VDC, 60s |
| Insulation Resistance | >100MΩ at 1000VDC |
| Overload Capacity | 1.4 × rated current for 1 minute, with at least 15-minute intervals |
| Maximum Cable Length | 400m for shielded cable; 300m for unshielded cable |
| Protection Rating | IP00 / IP20 |
| Insulation Class | T40 / F (155°C) |
| Flame Retardant Rating | UL94 V-2 |
| Product Standard | GB/T 15287/8 |
- Common-Mode and Differential-Mode Suppression: The filtering network is designed to attenuate both common-mode and differential-mode electromagnetic interference.
- Bidirectional EMI Suppression: The filter can attenuate interference traveling between the power supply and connected equipment, helping reduce unwanted noise transmission in both directions.
- VFD Application Compatibility: Designed for variable frequency drive systems where switching-related electromagnetic interference and conducted noise require additional suppression.
- Multi-Stage Filtering: The combination of common-mode choke, X capacitors, Y capacitors, and resistive elements provides multi-stage filtering performance.
- Wide Electrical Range: Rated voltage options from 220VAC to 1140VAC and rated current options from 5A to 1600A support a wide range of industrial power applications.
- Low Leakage Current Design: The filtering structure is designed with consideration for leakage current and system grounding requirements.
- Long Cable Applications: Suitable configurations are available for VFD systems using long motor cables, subject to actual drive, cable, motor, and installation conditions.
- Customized Selection: Dufew Electric can evaluate rated voltage, current, frequency, cable length, installation conditions, and other application parameters for product selection.
The Electromagnetic Interference Filter is suitable for industrial applications where electromagnetic compatibility and power quality are important, including:
1. Industrial equipment with stringent electromagnetic compatibility requirements.
2. Systems using multiple VFDs where electromagnetic interference between drives needs to be controlled.
3. VFD input applications where conducted or radiated interference may affect the power network or nearby equipment.
4. VFD systems affected by electrical disturbances, harmonic interference, or excessive electromagnetic noise.
5. Industrial equipment requiring additional protection against interference-related abnormal operation.
6. Industrial manufacturing and automation equipment.
7. Renewable energy and energy storage systems using power electronic equipment.
8. Motor drive systems with long cable runs or demanding electromagnetic environments.
Selecting an Electromagnetic Interference Filter requires more than matching voltage and current. The filter should be evaluated according to the complete electrical system, equipment configuration, and installation environment to ensure that the selected specification is suitable for the intended application.
Dufew Electric can support technical evaluation based on rated voltage and current, operating frequency, VFD power rating, common-mode and differential-mode interference, motor cable length, shielded or unshielded cable configuration, grounding conditions, installation space, thermal requirements, electromagnetic environment, and customer drawings or technical specifications.
For customized projects, customers can provide electrical specifications, technical drawings, physical samples, equipment information, or application conditions for engineering evaluation. Based on these requirements, Dufew Electric can supply standard products or develop application-specific filter configurations.
Select the filter's rated voltage and rated current according to the VFD power rating and electromagnetic environment. As a general selection guideline, the filter's rated current can be selected at approximately 1.2--1.5 times the equipment's rated current, subject to the actual application and manufacturer's recommendations. The filter's rated voltage must match the VFD operating voltage.
Check the enclosure for damage, verify that the terminals are intact, and confirm that product markings and specifications are clearly visible.
Install the filter at the equipment power entry point or at the input side of the interference source, such as a VFD, and keep it as close as practical to the protected equipment.
When installed on a metal control cabinet, ensure sufficient metal-to-metal contact between the filter enclosure and cabinet to support heat dissipation and electromagnetic shielding.
Use the designated mounting holes to secure the filter inside the control cabinet or on the mounting plate. Ensure that the filter is firmly installed and that impedance matching and grounding requirements are properly considered.
Connect the filter in series between the power supply and the VFD input according to the wiring diagram. Do not reverse the input and output terminals.
The grounding terminal must be reliably connected to protective earth. Keep the grounding connection as short as practical; a grounding conductor length of no more than 30cm is recommended.
Do not bundle the filter input wires together with the load-side or output wires. Doing so can increase electromagnetic coupling between the input and output sides and significantly reduce the filter's ability to suppress EMI.
Input and output wiring should be routed separately to minimize unwanted coupling.
After confirming that all connections are correct, power on the system and monitor the VFD operating condition. Verify whether the expected reduction in electromagnetic interference and abnormal operating conditions has been achieved.
| Comparison Factor | Dufew Integrated Composite EMI Filter | Conventional Simple Filter |
|---|---|---|
| Filtering Structure | Multi-stage filtering using a combination of common-mode choke, X capacitors, Y capacitors, and resistive elements | Typically relies on a simpler single-stage inductive structure |
| EMI Suppression | Designed to address both common-mode and differential-mode interference | High-frequency interference suppression may be limited depending on the filter structure |
| Thermal Management | Integrated structural design can support more organized component arrangement and thermal management | Component concentration may increase localized heat accumulation under continuous high-load conditions |
| Installation | Integrated filter configuration can simplify mounting and electrical connection | Separate filtering components may require additional mounting and wiring |
| Material Management | One integrated unit can simplify material coding and inventory management | Multiple components may increase the number of material items |
| Application Range | Suitable for VFD systems and industrial environments with demanding EMI requirements | More suitable for relatively simple applications depending on the electrical environment |
Dufew Electric is a China-based manufacturer and supplier of power electronics components, with manufacturing capabilities covering industrial resistors, braking systems, reactors, EMI filters, power filters, transformers, and customized electrical components. For Electromagnetic Interference Filters, production and inspection are carried out according to product specifications, applicable technical requirements, and customer requirements.
The manufacturing process covers material selection, component assembly, electrical testing, performance verification, final inspection, packaging, and shipment. Key quality checks may include:
- Rated voltage and current verification
- Insulation resistance testing
- Dielectric strength testing
- Electrical performance testing
- Visual and dimensional inspection
- Terminal and connection inspection
- Final product inspection
Product specifications and inspection requirements are controlled throughout production to maintain consistent electrical performance and product quality. Product-specific test records and technical documentation can also be provided according to project requirements.
Dufew Electric maintains relevant quality certifications, product documentation, and testing records to support customer evaluation and procurement requirements.
Applicable certificates and technical documents can be provided for review according to the specific product, project, and customer requirements.
As a power electronics components supplier in China, Dufew Electric supports international B2B orders from product selection and sample evaluation through production, inspection, packaging, and shipment.
Typical delivery arrangements can be coordinated according to order volume, product dimensions, destination, lead time, and customer requirements.
Available logistics options may include:
- Sea Freight: Suitable for regular and large-volume international orders.
- Air Freight: Suitable for urgent shipments, samples, and smaller-volume orders.
- Express Delivery: Suitable for technical samples and small packages where faster delivery is required.
- Customer-Designated Forwarder: Dufew Electric can coordinate shipment with the customer's nominated logistics provider when required.
Export packaging can be arranged according to product structure and transportation requirements to help protect electrical components during handling and international transit.
Dufew Electric focuses on power electronics components including resistors, braking systems, reactors, Electromagnetic Interference Filters, power filters, and transformers.
Product selection can be evaluated according to electrical parameters, VFD characteristics, cable length, electromagnetic environment, installation conditions, and other system requirements.
Dufew supports customized electrical specifications, configurations, drawings, samples, and application-specific requirements subject to engineering evaluation.
Manufacturing includes material inspection, controlled assembly, electrical testing, final inspection, and product documentation according to applicable requirements.
Dufew Electric supports equipment manufacturers, system integrators, distributors, OEM customers, and industrial users with product supply and international logistics coordination.
Its filtering network attenuates unwanted noise traveling between the power supply and connected equipment, helping reduce both incoming and outgoing electromagnetic interference.
Yes, when additional EMI suppression is required. Reactors primarily address current harmonics and power disturbances, while EMI filters target electromagnetic noise. They can therefore complement each other.
No. The conductors are electrically insulated while sharing the same magnetic core. Under normal differential-mode operation, their magnetic fluxes largely cancel each other.
No. X capacitors are used across line conductors for differential-mode noise, while Y capacitors connect between power lines and ground for common-mode noise. They have different safety and insulation requirements.
Dufew Electric manufactures power electronics components for motor drives, industrial automation, renewable energy, energy storage, and power control systems. With engineering support, controlled production, electrical testing, customization, and global B2B supply capabilities, we provide reliable solutions tailored to diverse industrial requirements.
Contact Dufew Electric for product selection, technical specifications, customization, samples, and international supply.
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No. 364, Kangyang Road, Huangdai Town, Xiangcheng District, Suzhou City, Jiangsu Province, China
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