Overview
The AG12-0.72 series indoor low-voltage current transformers are precision electromagnetic devices engineered for accurate current measurement and energy metering in 0.72 kV class AC distribution systems. Designed with a compact plastic case, these window-type transformers deliver galvanically isolated secondary current signals proportional to the primary circuit, ensuring reliable performance in commercial and industrial metering, load monitoring, and motor protection applications.
Built for indoor use, the AG12-0.72 features a ring-type magnetic core and a pass-through primary conductor design, enabling easy installation on busbars or cables. Its robust plastic housing provides mechanical protection and stable dielectric properties, meeting stringent insulation requirements for low-voltage environments. Compliant with IEC60044-1 and GB1208 standards, the transformer supports standard 5 A secondary output with accuracy classes of 0.5 or 1.0, making it ideal for revenue-grade metering and system monitoring.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class | 0.72 kV |
| Rated voltage | 720 V |
| Rated frequency | 50/60 Hz |
| Rated secondary current | 5 A |
| Accuracy classes | 0.5, 1.0 |
| Rated burden | 1–15 VA |
| Security factor (FS) | <5 |
| Dielectric test | 4 kVeff, 1 min |
| Ambient temperature | −5°C to +55°C |
| Construction type | Indoor plastic case |
Model Designation
AG12-0.72/XX/YY
- AG12 — Indoor plastic case current transformer series
- 0.72 — Rated voltage class in kV
- XX — Rated primary current in amperes (A)
- YY — Aperture size in millimeters (mm)
Construction
The AG12-0.72 features a window-type, single-core design with a ring-type magnetic core enclosed in a durable plastic case. The primary conductor passes directly through the aperture without dedicated terminals, while the secondary winding is accessible via standard K1/K2 (or S1/S2) terminals marked for correct polarity. The housing provides integrated insulation suitable for indoor low-voltage service, offering protection against dust and mechanical stress while maintaining required electrical clearances. This cast-resin-free plastic construction ensures lightweight handling, corrosion resistance, and long-term dimensional stability in typical indoor switchgear environments.
Technical Parameters
Service Conditions
- Installation environment: Indoor installation only
- Altitude: Not exceeding 1000 m above sea level (higher altitude requires specification)
- Ambient temperature: −5°C to +55°C
- Relative humidity: Daily average ≤ 95%, monthly average ≤ 90% (at +20°C reference)
- Environmental conditions: Free from corrosive gases or vapors; free from explosive or flammable media; no severe vibration, mechanical shock, or impact
Technical Parameters
This section provides selection-oriented technical data for the AG12-0.72 series indoor plastic case current transformers used in 0.72 kV class AC systems (50/60 Hz). Data shown below is intended for preliminary selection of ratio, accuracy class, and rated burden combinations.
Data Reference Table 1: AG12-0.72/45/14 Series
| Rated Current (A) Primary/Secondary |
Accuracy Class | Rated Burden (VA) |
|---|---|---|
| 35/5A–40/5A | 3 | 1 |
| 50/5A | 1.0 | 1 |
| 60/5A | 1.0 | 1.5 |
| 75/5A–80/5A | 1.0 | 1.5 |
| 100/5A | 1.0 | 1.5 |
Data Reference Table 2: Model-Specific Configurations
| Model | Rated Current (A) Primary/Secondary |
Rated Burden
(VA) |
Accuracy
Class |
Rated
Voltage |
Rated
Frequency |
|---|---|---|---|---|---|
| AG12-0.72/62/30 | 50/5A–300/5A | 1.5–5 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/62/40 | 150/5A–800/5A | 2.5–10 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/74/40 | 150/5A–800/5A | 2.5–10 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/74/50 | 250/5A–1000/5A | 5–10 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/86/60 | 250/5A–1500/5A | 5–15 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/104/80 | 300/5A–2000/5A | 5–15 | 1.0–0.5 | 720V | 50/60Hz |
| AG12-0.72/140/100 | 1000/5A–4000/5A | 15–60 | 1.0–0.2 | 720V | 50/60Hz |
Installation & Wiring
Outline Dimensions
The dimensional drawing illustrates key measurements corresponding to the table above. Dimension A represents overall height, B is width, C is the aperture diameter (Φ6.6 mm for most variants), D and E relate to mounting features, F is total depth, G indicates window height, and H shows base width where applicable. Ensure adequate space around the unit for airflow and access during installation.
Wiring Diagram
Connect the secondary terminals to the measuring instrument or protective relay as shown. The primary conductor passes through the central aperture without electrical connection. Polarity must be observed: terminal marked ‘P1’ or ‘H1’ should face the power source side. Always verify correct wiring before energizing the system.
Selection & FAQs
Selection Guide
- Select the primary ratio from the maximum load current and desired measurement range.
- Choose the AG12 aperture variant by conductor dimensions, insulation clearance, and panel space.
- Specify class 1.0, 0.5, or 0.2 according to metering accuracy requirements and model availability.
- Calculate device and cable burden, then choose a model with sufficient 1VA–60VA rated output.
- Confirm 5A secondary compatibility, mounting, polarity, terminal access, grounding, and indoor conditions.
Frequently Asked Questions
Q1: What voltage systems is the AG12-0.72 designed for?
It is designed specifically for 0.72 kV class AC systems operating at 50/60 Hz. Ensure your system voltage does not exceed this rating. Contact us for higher voltage requirements.
Q2: Can this current transformer be installed outdoors?
No, the AG12-0.72 is strictly for indoor installation only. It requires an environment free from corrosive gases, explosive media, and severe vibration. Confirm your site conditions meet these specifications.
Q3: Which accuracy classes are available for this low-voltage CT?
The AG12-0.72 series offers accuracy class 1.0 for measurement and class 3 for indication. Rated burden ranges from 1 VA to 1.5 VA depending on the primary ratio. Specify your exact ratio for detailed selection.
Q4: Are there special requirements for high-altitude installations?
Standard models are rated for altitudes not exceeding 1000 m above sea level. Higher altitude installations require special design specifications. Please provide your exact site altitude for factory verification.
Q5: How are quality and compliance verified before delivery?
Standard routine tests are conducted to ensure compliance with technical parameters. Specific certification or additional type test requirements are subject to confirmation. Contact our sales team for detailed test reports.
Q6: When should this plastic case CT be selected?
This indoor plastic case current transformer is primarily used for current measurement in 0.72 kV AC power distribution systems. It supports standard 5A secondary output configurations. Verify your panel dimensions before ordering.