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High-Precision Three-Phase Digital Voltmeter & Ammeter from China Suppliers and Factory for Industrial Use
Product Overview
1. Three-Phase Digital Voltmeter
1.1 Measuring Range
The voltmeter offers two measurement configurations to accommodate low, medium, and ultra-high voltage three-phase systems:
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Direct Measurement Range: 0 ~ 600 V AC
This range supports direct connection to three-phase low-voltage systems (e.g., 380 V, 400 V, 440 V, 600 V) without external signal conditioning equipment. It is ideal for on-site monitoring of motor control centers, distribution panels, and light industrial load systems. -
Extended Measurement Range (With Accessory Voltage Transformer - PT): 0 ~ 9999 kV AC
For high-voltage (HV) and extra-high voltage (EHV) system monitoring, the voltmeter is paired with a voltage transformer (PT) calibrated to a standard secondary output of 100 V AC. The primary voltage range (0 ~ 9999 kV) is determined by the PT ratio (e.g., 110 kV/100 V, 500 kV/100 V), enabling safe and accurate measurement of transmission lines, substations, and high-voltage equipment. The PT provides electrical isolation between the high-voltage primary circuit and the voltmeter, ensuring operator safety and device protection.
1.2 Core Measurement Features
- Real-time monitoring of line-to-line (UAB, UBC, UCA) and line-to-neutral (UA, UB, UC) voltages in three-phase systems.
- True RMS measurement algorithm, ensuring accuracy even with distorted waveforms caused by non-linear loads (e.g., variable frequency drives, rectifiers).
- Digital display with clear, high-visibility readings for quick on-site verification.
2. Three-Phase Digital Ammeter
2.1 Measuring Range
The ammeter is designed with flexible current measurement capabilities, supporting both direct low-current measurement and extended high-current monitoring via current transformers:
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Direct Measurement Range: 0 ~ 10 A AC
This range allows direct connection to three-phase circuits with low current loads (e.g., small motors, lighting systems, control circuits), eliminating the need for external CTs and simplifying installation. -
Extended Measurement Range (With Accessory Current Transformer - CT): 0 ~ 9999 A AC
For high-current system monitoring, the ammeter is integrated with a current transformer (CT) rated for a standard secondary output of 5 A AC. The primary current range (0 ~ 9999 A) is defined by the CT ratio (e.g., 100 A/5 A, 500 A/5 A, 1000 A/5 A), making it suitable for measuring large industrial loads, generator output currents, and distribution feeder currents. The CT isolates the ammeter from high primary currents, preventing overload damage and ensuring measurement precision.
2.2 Core Measurement Features
- Accurate RMS current measurement for each of the three phases (IA, IB, IC), with optional display of total system current.
- Compatibility with standard CT ratios, enabling easy calibration and configuration for specific applications.
- Overload indication function to alert users of abnormal current conditions in the monitored system.
Technical Parameters
| Function & Shape Model |
Measure & Display | Shape Code (Figure Inside) | Selected Additional Functions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Three Phase Current | Three Phase Voltage | ⑨ 96×96 | ⑧ 80×80 | ⑦ 72×72 | ④ 48×48 | Communication Interface: RS485 | 2-Channels Switch Output | 1-Channels Analog Output | |
| SFS-□K3-3I | ● | √ | |||||||
| SFS-□K3-3U | ● | √ | |||||||
| SFN-□K3-3I | √ | √ | √ | √ | |||||
| SFN-□K3-3U | ● | √ | √ | √ | √ | ||||
| SFN-□K3-3I+RS | ● | √ | √ | √ | + | ||||
| SFN-□K3-3U+RS | ● | √ | √ | √ | 十 | ||||
| SFN-□K3-3I+2DO | ● | √ | 十 | ||||||
| SFN-□K3-3U+2DO | ● | √ | 十 | ||||||
| SFN-□K3-3I+1AO | ● | V | 十 | ||||||
| SFN-□K3-3U+1AO | ● | √ | 十 | ||||||
Frequently Asked Questions
What is the direct voltage measurement range of the Three-Phase Digital Voltmeter?
The direct measurement range is 0 ~ 600 V AC. This configuration supports direct connection to three-phase low-voltage systems (such as 380 V, 400 V, 440 V, and 600 V) without needing external signal conditioning equipment.
How does the voltmeter measure voltages up to 9999 kV?
For high-voltage (HV) and extra-high voltage (EHV) systems, the voltmeter is paired with a Voltage Transformer (PT) that has a standard secondary output of 100 V AC. The primary range (0 ~ 9999 kV) is determined by the PT ratio.
What is the difference between direct and extended current measurements on the ammeter?
Direct measurement supports low current loads from 0 ~ 10 A AC without external current transformers. Extended measurement supports high-current monitoring up to 9999 A AC by integrating with a Current Transformer (CT) rated for a standard 5 A AC secondary output.
Does the digital meter support True RMS measurement?
Yes, the digital voltmeter uses a True RMS measurement algorithm. This ensures accurate readings even when the waveforms are distorted by non-linear loads like variable frequency drives (VFDs) and rectifiers.
What additional communication and output functions are available?
Depending on the model selected, additional functions include an RS485 communication interface, 2-channels switch output (DO), and 1-channel analog output (AO).
What physical shape and panel dimensions are available for these meters?
The meters come in four standard panel sizes depending on the model: 96×96 mm (shape code ⑨), 80×80 mm (shape code ⑧), 72×72 mm (shape code ⑦), and 48×48 mm (shape code ④).