Sunwin WN-500L 500kW AC Liquid-Cooled Resistive Load Bank

1. Product Overview

The Sunwin WN-500L is a 500kW AC liquid-cooled resistive load bank designed for data centers, providing controlled load testing for three-phase AC power supplies. Its core advantage lies in its innovative liquid cooling system, which enables stable operation at full rated power while minimizing heat dissipation and noise in the test environment — making it ideal for indoor test facilities where traditional air-cooled solutions are impractical or difficult to deploy.

With pure resistive loading for high-precision power absorption, an on-board HMI touch screen, PC-based remote control and Modbus TCP communication, the WN-500L makes load verification of data center backup generators, UPS and power distribution systems quieter, cleaner and more reliable.

2. Why Data Centers Need Liquid-Cooled Load Testing

As AI computing infrastructure grows rapidly, rack power density in data centers keeps rising. Traditional air cooling is approaching its limits, and liquid cooling has become a key technology path for high-density data centers. At the same time, backup generators, UPS and power distribution systems must be verified through full-load testing (load bank testing) to ensure reliable power delivery in critical moments.

In this context, the value of a liquid cooled load bank becomes increasingly evident: compared with conventional air-cooled units, it discharges far less hot air into the test environment, operates at lower noise, occupies less space, and can be directly integrated with the data center liquid cooling loop for heat transfer — making it ideal for indoor testing, equipment room commissioning and data center commissioning. The WN-500L is engineered for exactly this need.

3. Key Technology Highlights

3.1 Innovative Liquid Cooling System

The WN-500L adopts a stainless steel grade 304 resistor tank with a liquid cooling circulation design, connecting to the chilled water system via flange connections (DN100 liquid in/out, DN15 air vent) to efficiently remove load-generated heat from the test environment. The unit supports continuous stable operation at full power, significantly reducing indoor temperature rise and noise for a quieter, cleaner testing process.

3.2 High-Precision Loading and Control

With 1kW load resolution and load accuracy of ≤±2%, the output power can be finely adjusted; the 400Vac three-phase four-wire input with IP67 Power-fit quick connectors (400A) ensures fast, safe and reliable wiring. Parallel connection control is supported, allowing multiple WN-500L units to be combined for larger testing capacity.

3.3 Intelligent Monitoring and Communication

The unit is equipped with a local built-in HMI touch screen for intuitive operation, and supports PC-based remote control and monitoring software. With Modbus TCP via an RJ45 Ethernet port, it can be integrated into host systems for remote start/stop, parameter setting and data acquisition, adapting to data center centralized monitoring and automated test workflows.

3.4 Comprehensive Safety Protection

The WN-500L is fitted with liquid in/out temperature, flow volume and pressure transducers, providing over-temperature, over-pressure and low air volume alarm and cut-out protection, along with electrical load branch fuse protection, a control circuit mains breaker and an air vent valve — safeguarding both the equipment and the test environment.

4. Main Technical Specifications

5. Typical Applications

For data center backup power testing, the WN-500L verifies the load capacity of backup generators, UPS and power distribution systems to ensure reliable emergency power. For data center commissioning and acceptance, it supports joint commissioning and acceptance of power supply and cooling systems (CDU), simulating the heat and power characteristics of real IT loads.

For indoor test facilities, the low-heat-dissipation, low-noise liquid cooling design makes it suitable for offices, equipment rooms and laboratories sensitive to heat and noise. For long-duration high-load continuous testing, the liquid cooling system supports sustained full-load operation, offering a professional alternative where air-cooled loads cannot meet the requirement.