Product Overview
The JDG4-0.5 indoor dry-type low-voltage voltage transformer is a single-phase indoor voltage transformer designed for voltage measurement, electrical energy metering, and relay protection in AC systems with rated voltage up to 0.5kV and rated frequency of 50Hz or 60Hz. It converts the primary voltage into a standardized secondary voltage signal for measuring instruments, energy meters, and protection devices.
The JDG4-0.5 series uses a dry-type C-core structure with primary and secondary windings installed on the center limb of the core. The product is suitable for low-voltage switchgear, metering panels, distribution cabinets, and power monitoring systems. It is typically applied in circuits where voltage signals are required for metering, power monitoring, and protection control.
Product Type
| Item | Specification |
|---|---|
| Product name | Indoor Dry-Type Low Voltage Potential transformer |
| Model series | JDG4-0.5 |
| Product structure | Single-phase indoor dry-type voltage transformer |
| Rated voltage class | 0.5kV and below low-voltage AC system |
| Rated frequency | 50Hz / 60Hz |
| Rated voltage ratio | (100-1140)V / 100V; common ratios include 220/100V, 380/100V and 500/100V |
| Installation location | Indoor |
| Typical applications | Voltage measurement, energy metering, power monitoring, relay protection |
Product Display
Main Applications
- Indoor low-voltage AC circuits rated up to 0.5kV
- Voltage measurement circuits in low-voltage distribution systems
- Electrical energy metering and power monitoring panels
- Relay protection circuits requiring a stable voltage signal
- Low-voltage switchgear, distribution cabinets, and metering cabinets
- Instrument power supply and electrical isolation between primary and secondary circuits
Key Technical Features
- Indoor dry-type design: Suitable for indoor low-voltage applications without oil insulation.
- Single-phase voltage transformer: Provides a standardized 100V secondary voltage signal for meters, relays, and monitoring devices.
- Wide primary voltage range: JDG4-0.5 can be specified for primary voltage from 100V to 1140V, with common secondary voltage of 100V.
- C-core structure: The iron core is made of quality cold-rolled silicon steel sheet and formed into a C-type magnetic structure.
- Metering and protection use: Applicable to voltage measurement, electrical energy metering, power monitoring, and relay protection circuits.
- Compact installation: The product has a small size, light weight, and fixed mounting structure for cabinet installation.
Working Principle
The JDG4-0.5 voltage transformer operates according to electromagnetic induction. The primary winding is connected to the measured low-voltage circuit, and the secondary winding outputs a reduced voltage signal, normally 100V, for meters, instruments, and relay devices. This allows the primary circuit voltage to be measured safely while providing electrical isolation between the power circuit and secondary equipment.
Model Designation
The model code can be interpreted as follows:
| Code | Meaning |
|---|---|
| J | Voltage transformer |
| D | Single-phase structure |
| G | Dry-type design |
| 4 | Design series code |
| 0.5 | Rated voltage class: 0.5kV |
| □ | Rated voltage ratio code according to selected specification |
Technical Data
| Item | Specification |
|---|---|
| Rated voltage class | 0.5kV and below |
| Rated primary voltage | 100V to 1140V according to project requirement |
| Rated secondary voltage | 100V; 100V to 230V can be confirmed by technical agreement |
| Rated frequency | 50Hz / 60Hz |
| Accuracy class | 0.5 class |
| Rated output | 15VA |
| Limit output | 100VA |
| Rated insulation voltage | 3kV |
| Power-frequency withstand voltage | 3000V / 1min, 50Hz |
| Installation location | Indoor |
| Applicable standards | GB/T 20840.3-2013, JJG 314-2010; project-specific requirements can be confirmed by agreement |
Rated Voltage Ratio, Accuracy and Output Reference
| Model | Rated Voltage Ratio |
Rated Frequency |
Accuracy Class |
Rated Output (VA) |
Limit Output (VA) |
Rated Insulation Voltage (kV) |
|---|---|---|---|---|---|---|
| JDG4-0.5 | (100-1140)V / 100V | 50-60Hz | 0.5 | 15 | 100 | 3 |
Note: Rated voltage ratio and secondary voltage can be confirmed according to project requirements. Final parameters are subject to technical agreement and nameplate data.
Service Conditions
- Installation location: indoor
- System voltage: 0.5kV and below
- Rated frequency: 50Hz / 60Hz
- Ambient temperature: -25°C to +40°C
- Altitude: not more than 1000m unless otherwise specified
- The product should be used in locations without rain, snow, direct outdoor exposure, severe pollution, or strong vibration.
- For special temperature, altitude, humidity, pollution level, or cabinet layout requirements, technical confirmation is recommended before ordering.
Standards & Compliance
The JDG4-0.5 series voltage transformer is designed for indoor low-voltage voltage measurement and metering applications. It can be supplied according to GB/T 20840.3-2013, JJG 314-2010, and project-specific technical requirements. Related GB/T 20840 series requirements may be confirmed according to the project acceptance standard and technical agreement.
Installation & Dimensions
The JDG4-0.5 series adopts an indoor dry-type fixed installation structure. The outline dimensions and installation hole positions should be confirmed with the approved drawing before cabinet design, wiring, or batch ordering.
Installation Reference
| Model | Typical
Structure |
Rated
Voltage Ratio |
Installation
Reference |
Remark |
|---|---|---|---|---|
| JDG4-0.5 | Indoor dry-type C-core structure | (100-1140)V / 100V | Base fixed installation | Confirm final dimensions
with approved drawing |
Unit: mm for dimensional drawings. Unmarked dimensional tolerance can be confirmed according to the final drawing.
Connection and Wiring Notes
- Primary terminals are marked as A and B(N), depending on the selected wiring method.
- Secondary terminals are marked as a, b(n), depending on the secondary circuit design.
- Confirm the voltage ratio, rated output, and accuracy class before wiring.
- The secondary circuit should be protected with suitable fuses according to the project wiring diagram.
- For three-phase measurement, JDG4-0.5 can be applied in 2PT three-phase three-wire or 3PT three-phase four-wire connection schemes according to the system design.
Installation and Safety Notes
- Confirm the product model, voltage ratio, accuracy class, rated output, and installation dimensions before installation.
- Install the voltage transformer in an indoor dry location without rain, snow, or severe pollution.
- Do not operate the voltage transformer beyond its rated output or limit output.
- Secondary wiring, grounding, fuse protection, and terminal connection should comply with project specifications and local electrical regulations.
- Installation and maintenance should be performed by qualified electrical personnel.
Ordering Information
Please provide the following information when ordering or requesting a quotation:
- Product model: JDG4-0.5
- Rated voltage ratio, such as 220/100V, 380/100V, 500/100V, or project-specified ratio
- Rated output and required accuracy class
- Rated frequency and operating environment
- Connection method, such as 2PT three-phase three-wire or 3PT three-phase four-wire
- Installation dimensions or cabinet layout requirements
- Quantity and application, such as metering, monitoring, or relay protection
- Special requirements for terminals, fuses, labels, drawings, inspection documents, certificates, or packaging
Selection Guidelines
- Confirm system voltage: Select JDG4-0.5 for indoor AC systems rated up to 0.5kV.
- Confirm voltage ratio: Select the primary and secondary voltage ratio according to the measured circuit and connected instrument requirement.
- Confirm rated output: The total burden of meters, relays, terminals, fuses, and secondary wiring should not exceed the rated output.
- Confirm accuracy class: Use 0.5 class when the circuit requires measurement or metering accuracy.
- Confirm connection method: Select 2PT or 3PT wiring according to the three-phase system and metering scheme.
- Confirm installation space: Check the outline drawing, terminal position, and cabinet clearance before batch installation.