WEM3080TD Guide: Delta and Dual Single-Phase Power Monitoring

Using WEM3080TD to Measure Three-Phase Delta and Dual Single-Phase Systems Product Overview Applicable System Types Three-Phase Three-Wire (Delta) Systems Dual Single-Phase Systems Wiring Instructions Three-Phase Delta Wiring Dual Single-Phase Wiring Summary of Wiring IAMMETER-Cloud Configuration Application Examples FAQs System Compatibility Summary About IAMMETER Solutions Products System

Using WEM3080TD to Measure Three-Phase Delta and Dual Single-Phase Systems

Product Overview

WEM3080TD is a Wi-Fi energy meter launched by IAMMETER, specifically designed for three-phase three-wire power systems (Delta configuration). It supports bidirectional energy metering (import/export), uploads data to the cloud via Wi-Fi, and provides interfaces like Modbus TCP/RTU and REST API, making it easy to integrate into energy monitoring and home automation systems.

In three-phase systems without a neutral line, WEM3080TD can monitor the entire power usage using two current transformers (CTs). It can also function as a dual single-phase energy meter in specific scenarios by using Phase B as a voltage reference, allowing one device to monitor two independent single-phase circuits.

Applicable System Types

WEM3080TD is mainly applicable to the following two system types:

Three-phase three-wire systems (Delta configuration): Common in industrial applications like motors, air conditioners, and compressors. These systems have three live wires and no neutral.
Dual single-phase systems: Monitoring two single-phase circuits sharing a common reference line (typically a neutral or one of the live lines), with WEM3080TD using the B-phase terminal as the reference.

Measurement principles for both scenarios are described below.

Three-Phase Three-Wire (Delta) Systems

In Delta systems, there is no neutral line. WEM3080TD is designed for such systems and hence lacks a neutral terminal. It uses a two-wattmeter method to measure total power: internally treating Phase B as the voltage reference. It calculates power using voltage and current between Phase A vs Phase B and Phase C vs Phase B.

In the IAMMETER system, Phase A and Phase C power readings represent the power between A-B and C-B respectively, and Phase B power is always 0. Two CTs on Phase A and Phase C can measure the total power even under unbalanced loads.

Dual Single-Phase Systems

By leveraging Phase B as a voltage reference, WEM3080TD can monitor two single-phase circuits that share a common reference line. Connect this common line to the B-phase voltage terminal, connect the two live wires to A and C terminals respectively, and install CTs on each. This way, WEM3080TD measures the power of both circuits independently.

Effectively, WEM3080TD acts as two single-phase meters: the A-phase channel measures circuit 1, and the C-phase channel measures circuit 2. Both circuits must share a reference line; otherwise, simultaneous monitoring isn’t possible.

Wiring Instructions

Correct wiring is essential for accurate measurements.

Three-Phase Delta Wiring

Wiring diagram	CT direction(K->L) indication

Voltage terminals: UA to Phase A, UB to Phase B (reference), UC to Phase C. Use two CTs:

CTa on Phase A
CTc on Phase C

CTb is left unconnected. CT arrows (K→L) must point toward the reference (B-phase). If negative power appears, reverse the CT direction or swap positions.

Dual Single-Phase Wiring

UB terminal connects to the common reference line. Live wire 1 goes to UA and CTa, Live wire 2 to UC and CTc. CT arrows must point toward the reference (UB). CTb remains unused.

Summary of Wiring

Voltage terminals (UA/UB/UC): Connect to three wires — either three live wires (Delta) or two live + one reference (dual single-phase).
CT Installation: Only CTa and CTc are used. Ensure CT arrows face the reference.
B-phase Reference: Serves as the voltage reference in both systems. B-phase channel shows 0 power.

IAMMETER-Cloud Configuration

After hardware installation:

Connect Wi-Fi: Use the app or browser to connect WEM3080TD to your Wi-Fi.
Add Device: Register and log in to IAMMETER-Cloud. Add the device using its serial number (SN).
Set Meter Type: Change from default "Single Phase" to "Three Phase" in the device settings.
Label CT Channels (optional): Assign roles (e.g., Grid, PV) to channels for clearer display.
Verify Data: A and C channels should show correct power, B should read 0. If needed, use the "reverse CT" setting.

For more details ,please refer to https://www.iammeter.com/quickstart/wem3080td-quickstart

Application Examples

1. Industrial Monitoring: Monitor Delta-fed equipment (motors, pumps, compressors) in factories without neutral. Connect WEM3080TD to the main line for real-time monitoring and analytics.

2. PV and Grid Monitoring: For homes with single-phase PV, use one channel for grid and the other for PV output, sharing the neutral line as a reference. IAMMETER-Cloud can display curves and usage metrics.

3. Dual-Circuit Monitoring: Monitor two single-phase loads (e.g., AC and lighting) sharing a neutral. Use WEM3080TD to record both circuits independently in one device.

FAQs

Q: Does WEM3080TD support three-phase four-wire (Wye)? A: No. It lacks a neutral terminal. Use WEM3080T for such systems.
Q: Why is B-phase power always 0? A: It’s the voltage reference and not measured directly.
Q: Are two CTs enough for Delta measurement? A: Yes. WEM3080TD uses the two-wattmeter method. A third CT is unnecessary.
Q: Why is a phase showing negative power? A: Likely due to incorrect CT direction. Reverse the CT or adjust in the app.
Q: Can I use it for a single-phase system? A: Technically yes, but it’s not recommended. Use WEM3080 for single-phase systems.

System Compatibility Summary

System Type	WEM3080TD Compatibility
Three-phase Delta	✔️ Supported
Dual single-phase	✔️ Supported (shared reference)
Three-phase Wye (with N)	❌ Not supported
Single-phase (1 circuit)	⚠️ Usable but not recommended

Note: For three-phase four-wire metering, see https://www.iammeter.com/newsshow/blog-electrical-meter

WEM3080TD is a flexible and cost-effective solution for specific use cases without a neutral wire or for dual single-phase circuits. Proper wiring and configuration ensure full functionality and accurate energy monitoring.

About IAMMETER

IAMMETER is a company focused on energy management products and services, offering smart energy meters, management apps, and cloud platforms.

Our goal is to help customers manage, utilize, and save energy effectively, reducing electricity bills through smart monitoring and analysis.