Overview
The RECT-0.66 series indoor cast-resin current transformers are precision electromagnetic devices engineered for accurate current measurement in low-voltage AC power systems. Operating on the principle of electromagnetic induction, they deliver a galvanically isolated secondary current proportional to the primary current, supporting systems with rated insulation up to 0.72/3kV. Designed for indoor use, these transformers ensure reliable performance in commercial and industrial low-voltage distribution networks.
Available in three models—RECT-38A, RECT-66A, and RECT-78A—the series offers aperture diameters of Ø38 mm, Ø66 mm, and Ø78 mm respectively, accommodating a wide range of conductor sizes. With high accuracy class 0.2, they are well-suited for energy metering, system monitoring, and protective relaying applications in both 50Hz and 60Hz environments.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| Insulation Level | 0.72/3 kV |
| Frequency | 50/60 Hz |
| Accuracy Class | 0.2 |
| Primary Current Range | 100 A – 800 A |
| Secondary Current | 5 A (standard) |
| Aperture Options | Ø38 mm, Ø66 mm, Ø78 mm |
| Indoor Use | Yes |
| Insulation Material | Cast resin |
| Standards Compliance | GB20840.1-2010, GB20840.2-2014 |
Construction
The RECT-0.66 series features a robust window-type housing made from high-quality cast-resin insulation material, ensuring excellent dielectric strength and long-term environmental resistance. The core is constructed from grain-oriented electrical steel to minimize losses and enhance measurement accuracy. Terminals are tin-plated copper for reliable connectivity and corrosion resistance. The compact, solid design provides mechanical stability and protection against moisture, dust, and thermal stress, making it suitable for demanding indoor low-voltage installations.
Technical Parameters
Service Conditions
- Rated Insulation Level: 0.72/3kV
- Rated Frequency: 50Hz / 60Hz
- Rated Secondary Current: 5A or 1A
- Ambient Temperature: -25°C to +40°C
Technical Parameters
The RECT-0.66 indoor cast-resin current transformer is available in multiple models with varying primary current ratings, accuracy classes, and output capacities to suit diverse metering and protection applications.
Model Specifications
| Model | Rated Primary Current (A) |
Accuracy Class |
Rated Output (VA) |
Aperture Diameter |
|---|---|---|---|---|
| RECT-38A | 100 | 0.2 | 5 | Ø38mm |
| RECT-66A | 150 | 0.2 | 2.5 | Ø66mm |
| RECT-66A | 200-300 | 0.2 | 12.5 | Ø66mm |
| RECT-78A | 300-800/5 | 0.2 | 12.5 | Ø78mm |
Installation & Wiring
The RECT-0.66 series current transformers feature a window-type design for easy installation around conductors or busbars. The primary conductor passes through the aperture (window) of the transformer, requiring no electrical connection to the primary circuit.
Installation Steps:
- Mount the transformer to a flat surface using the base plate mounting holes
- Pass the primary conductor through the aperture
- Connect the secondary wires to the terminal block (S1, S2)
- Ensure proper polarity marking (P1/P2) for accurate measurement
Terminal Configuration:
- Secondary terminals protected by transparent cover
- 3×M5 dual-purpose terminal screws
- Lead seal port for tamper prevention
Selection & FAQs
Selection Guide
- Select the 100A–800A ratio from maximum current and the required class 0.2 metering range.
- Choose the 38mm, 66mm, or 78mm aperture by conductor size and insulation clearance.
- Specify a 1A or 5A secondary compatible with the instrument and cable length.
- Calculate total secondary burden and confirm the selected model’s 2.5VA–12.5VA output.
- Verify mounting, conductor direction, terminal access, polarity, grounding, and indoor temperature limits.
Frequently Asked Questions
Q1: Which aperture diameter fits my primary conductor size?
Select based on your cable or busbar dimensions. Available apertures are Ø38mm, Ø66mm, and Ø78mm across the RECT-38A, 66A, and 78A models. Contact us for custom sizes if needed.
Q2: What details are required to process a custom order?
We need your primary current, accuracy class, and output capacity requirements. Standard models range from 100A to 800A with a 0.2 class and up to 12.5VA. Provide these parameters to initiate the quotation process.
Q3: Can you manufacture custom primary current ratings beyond 800A?
Yes, customized specifications are available upon request. If your required primary current exceeds the standard 100A to 800A range, consult the manufacturer directly. We will determine the exact technical parameters for your project.
Q4: Are these transformers suitable for outdoor installation environments?
No, they are strictly designed for indoor applications. The cast resin insulation and -25°C to +40°C ambient temperature rating are optimized for indoor switchgear. Verify your installation environment meets these conditions before ordering.
Q5: How do I choose between 5A and 1A secondary currents?
Both 5A and 1A rated secondary currents are offered. The 1A option reduces burden for longer cable runs, while 5A suits local panels. Specify your preference during the inquiry stage.
Q6: Is the RECT-0.66KV suitable for medium voltage switchgear?
No, it is strictly a low voltage current transformer. The rated insulation level is 0.72/3kV, designed specifically for 0.66kV indoor distribution networks. Verify your system voltage matches this specification before procurement.