WRx Series Image

High Power DC Electronic Loads
Active Resistance + Microchannel Water Cooling

Utilizing Magna-Power’s new patent pending Active Resistance Technology in combination with the company’s internally manufactured microchannel water-cooled heatsinks, the WRx Series addresses high power DC applications where exhaust heat control is essential. The WRx Series greatly increases power density compared air-cooled alternatives. An integrated solenoid controls the flow of water to avoid condensation. Full power can be achieved using conventional water, with water inlet temperatures up to 25 °C.

Magna-Power's Active Resistance heat dissipation technology utilizes a switched binary matrix of resistances and MOSFET network, combined with Magna-Power's new MagnaLINK™ distributed DSP architecture, the WRx Series delivers the same features and performance as traditional electronic loads, at a fraction of the price. Beyond voltage, current, resistance, and power control modes, the WRx Series also provides a rheostat control mode, allowing direct control of the product's internal resistance network.

Key Features

MagnaLINK™ Distributed DSP Architecture

Magna-Power’s MagnaLINK™ technology provides distributed Texas Instrument DSP control across power processing stages inside the MagnaLOAD DC electronic load. This technology follows a significant internal development cycle from Magna-Power to provide a unified digital control platform across its electronic loads and power supplies, featuring fully digital control loops, adjustable control gains, programmable slew rates, function generation, and many new advanced control technologies.

Many Control Modes Including Rheostat Mode

To accommodate a variety of DC sources, all WRx Series MagnaLOADs come with several distinct control modes, including: Voltage Mode, Current Mode, Power Mode, Resistance Mode, Shunt Regulator Mode, and Rheostat Mode. Preference for DC regulation is given to the parameter in the selected mode within the programmed set-points. Using the MagnaLOAD's set-points and trip settings, the product can configured to either trip with a fault when a limit is exceeded or to cross-over into a different regulation state.

Shunt Regulator Mode turns the MagnaLOAD into a high-speed smart braking resistor, engaging the DC input only when a specified voltage is exceeded by a user-defined percentage, while limiting the shunt current to a programmed set-point.

Rheostat Mode, unique to the ARx and WRx Series, bypasses the digital controls to provide direct control of the MagnaLOAD's internal resistor network. Using this mode, true resistance step load response can be achieved without the traditional bandwidth limitations. While the standard operating modes offer 16-bit programming resolution, Rheostat Mode provides 31 different resistor states.

Digital Master-Slaving: Expandibility Without Compromise

This is a planned feature that will be available via a future firmware update.

All MagnaLOADs come standard with a MagnaLINK™ Input and a MagnaLINK™ Output port, which provides plug and play digital master-slaving. Simply connect the master's MagnaLINK™ Output to the slave's MagnaLINK™ Input and the MagnaLOADs will automatically configure themselves for master-slave operation based on the populated ports. Buffered digital MagnaLINK™ connections means many MagnaLOADs can be daisy-chained in master-slave operation.

The internal MagnaLINK™ protocol was developed with expandability at the forefront. When configured for master-slave operation, the master controller takes control of all the slave's digital "targets." With this digital master-slaving strategy, it is completely transparent whether the unit is operating as a stand-alone product or in master-slave. 

Extensive Programming Support

All WRx Series MagnaLOADs come with a dedicated National Instruments LabVIEW™ driver, Interchangeable Virtual Instrument (IVI) driver, and support for a wide range of Standard Commands for Programmable Instrumentation (SCPI). These programming interfaces support full control, measurement, and monitoring of the MagnaLOAD. All of the MagnaLOAD's available communication interfaces are supported by these drivers and command sets, including: USB, RS485, LXI TCP/IP Ethernet, and IEEE-488 GPIB.

Showcased in the following basic code examples, SCPI commands provide the simplest form of communication by using plain ASCII text and parameters sent over a basic socket connection. Over 50 commands are provided, with detailed documentation in the WRx Series User Manual.

Basic Code Examples
import visa
        rm = visa.ResourceManager()
        magna_power = rm.open_resource(USB::0x0403::0x6015::1201-2358::INSTR)
        magna_power.write('VOLT 1000')
        magna_power.write('CURR 20')
magna_power = visa('ni','USB::0x0403::0x6015::1201-2358::INSTR');
        idn = fscanf(magna_power)
        fprintf(magna-power,'VOLT 1000')
        fprintf(magna-power,'CURR 20')
string resourceString = "USB::0x0403::0x6015::1201-2358::INSTR";
        mbSession = (MessageBasedSession)ResourceManager.GetLocalManager().Open(resourceString);
        string idn;
        mbSession.Timeout = 3000;
        idn = mbSession.Query("*IDN?");
        mbSession.Write("VOLT 1000");
        mbSession.Write("CURR 20");

Configurable External User I/O

Beyond the front panel and computer controls, all MagnaLOADs come standard with a 25-pin D-Sub connector designated as the External User I/O. This connector provides :

  • 8 Digital Outputs
  • 4 Digital Inputs
  • 4 Analog Outputs
  • 4 Analog Inputs

All the analog-digital I/O ports are configurable, allowing the user to select which parameters they want to control and monitor. This configurable I/O scheme reduces complexity, eases PLC integration and allows control parameters from various interfaces simultaneously.

The MagnaLOAD's configurable analog inputs provide 0-10V programming from PLCs and external D/A converters.

Integrated Arbitrary Waveform Generation

This is a planned feature that will be available via a future firmware update.

All MagnaLOADs provide four user programmable arbitrary waveforms. Each arbitrary waveform can consists of up to 1024 points, each point with the following settings:

  • Voltage, Current, Power, and Resistance Set Points
  • Time Period
  • Rise and Fall Slew Rates
  • Stop, Loop, or Jump-to-Point Setting

With the integrated arbitrary waveform generation, the MagnaLOAD can easily be used to provide a wide range of user-generated waveforms including step load transitions or pulsed DC loading.

MagnaWEB Software Interface

Magna-Power's next generation software interface, MagnaWEB, provides intuitive and user-friendly web-browser based controls for programming and measurement read-back of the MagnaLOAD's activity. Virtually all of the MagnaLOAD's available functions can be controlled and monitored from the MagnaWEB software over any of product's installed communication interfaces.

MagnaWEB uses a server-client software model to provide access to the MagnaLOAD from nearly any device and operating system. Install and run the MagnaWEB software locally on Windows, OSX or Linux and, using a web browser, access the server connected to the MagnaLOAD from a variety of devices including other desktops, tablets or smart-phones.

Designed and Manufactured in the USA, Available Worldwide

MagnaLOADs are designed and manufactured at Magna-Power's vertically integrated USA manufacturing facility in Flemington, New Jersey. Heat-sinks and chassis are machined from aluminum. High-power resistor modules are fabricated and rigorously tested. An automated surface-mount production line places components on printed circuit boards for control, auxiliary power, and display circuits. And finally after assembly, products undergo comprehensive test and calibration, followed by an extended burn-in period.


There are many possible configurations for the WRx Series product. Using the following ordering guide and models chart to define the best model for your application.

Model Maximum Power Maximum Voltage Maximum Current Package Type
WRx-12.5-200-130 12.5 kW 200 Vdc 130 Adc Rack-mount
WRx-12.5-500-52 12.5 kW 500 Vdc 52 Adc Rack-mount
WRx-12.5-1000-26 12.5 kW 1000 Vdc 26 Adc Rack-mount
WRx-25-200-260 25 kW 200 Vdc 260 Adc Floor-standing
WRx-25-500-104 25 kW 500 Vdc 104 Adc Floor-standing
WRx-25-1000-52 25 kW 1000 Vdc 52 Adc Floor-standing
WRx-50-200-520 50 kW 200 Vdc 520 Adc Floor-standing
WRx-50-500-208 50 kW 500 Vdc 208 Adc Floor-standing
WRx-50-1000-108 50 kW 1000 Vdc 108 Adc Floor-standing
WRx-75-200-780 75 kW 200 Vdc 780 Adc Floor-standing
WRx-75-500-312 75 kW 500 Vdc 312 Adc Floor-standing
WRx-75-1000-156 75 kW 1000 Vdc 156 Adc Floor-standing
WRx-100-200-1040 100 kW 200 Vdc 1040 Adc Floor-standing
WRx-100-500-416 100 kW 500 Vdc 416 Adc Floor-standing
WRx-100-1000-216 100 kW 1000 Vdc 216 Adc Floor-standing

Operating Profile

With its combination of resistor and linear elements, the WRx Series DC electronic load provides two distinct operating profiles: High Power Range and Low Power Range.

The operating profiles figures below apply to to all WRx Series models, normalized about the model's maximum voltage, current, and power ratings.


AC Input Specifications

  • AC Input Voltage 85-265 Vac, 1-phase
  • AC Input Frequency 45 Hz to 440 Hz

External User I/O Specifications

  • Digital Input Voltage 5 V
  • Digital Input Impedance 10 kO
  • Digital Monitoring Voltage 5 V, 32 mA capacity
  • Digital Reference Voltage 5 V, 20 mA capacity
  • Analog Programming Voltage 0-10 V
  • Analog Input Impedance 10 kO
  • Analog Programming Resolution 12-bit, 0.025%
  • Analog Monitoring Voltage 0-10 V, 3 mA capacity
  • Analog Reference Voltage 10 V, 20 mA capacity
  • Provided Reference Voltages 5 V, 10 V
  • Interlock Input 5 V

Water Cooling Specifications

  • Maximum Inlet Temperature 25 °C
  • Maximum Inlet Pressure 80 PSI
  • Minimum Flow Rate (12.5 kW) 1.5 GPM
  • Minimum Flow Rate (25 kW) 3.0 GPM
  • Minimum Flow Rate (50 kW) 6.0 GPM
  • Minimum Flow Rate (75 kW) 9.0 GPM
  • Minimum Flow Rate (100 kW) 12.0 GPM

Programming Specifications

  • Current Resolution 16-bit, 0.0015%
  • Voltage Resolution 16-bit, 0.0015%
  • Power Resolution 16-bit, 0.0015%
  • Resistance Resolution 16-bit, 0.0015%

Environmental Specifications

  • Operating Temperature 0 to 50 °C
  • Storage Temperature -25 to 85 °C
  • Humidity (Non-Condensing) = 95%
  • Altitude Up to 10,000 ft (3,000 m)
  • Air Intake (All Models) Front
  • Air Exhaust (All Models) Rear

Connectivity Specifications

  • USB Host (Front) Standard, Type B
  • USB Host (Rear) Standard, Type B
  • RS485 (Rear) Standard, RJ-45
  • LXI TCP/IP Ethernet (Rear) Optional, RJ-45
  • IEEE-488 GPIB (Rear) Optional
  • MagnaLINK™ Standard, RJ-25 x 2
  • External User I/O Standard, 25-pin D-sub F

Physical Specifications

The size of WRx Series MagnaLOADs vary according to the product's maximum power output rating, in accordance with the following table:

Power Package Size (H x W x D) Weight
12.5 kW Rack-mount (4U) 7” x 19” x 24” in (17.8 x 48.2 cm x 60.9) 165 lbs (74.8 kg)
25 kW Floor Standing 30.7” x 24” x 31.5” in (78.0 x 61.0 x 80.0 cm) 455 lbs (206.4 kg)
50 kW Floor Standing 58¼" x 24" x 31.5" in (148.0 x 61.0 x 80.0 cm) 785 lbs (356.1 kg)
75 kW Floor Standing 58¼" x 24" x 31.5" in (148.0 x 61.0 x 80.0 cm) 1115 lbs (505.8 kg)
100 kW Floor Standing 74" x 24" x 31.5" in (188.0 x 61.0 x 80.0 cm) 1445 lbs (655.4 kg)

MagnaLOAD Front Panel

  • START: Enables the DC input bus
  • STOP: Disables the DC input bus
  • Voltage measurement display
  • Current measurement display
  • 4-line character display featuring a menu system, operating status and modes, product messages with diagnostic codes, resistance measurement display, and power measurement display
  • Control power switch, energizes the control circuits without engaging DC bus
  • LED indicator that the DC input is enabled
  • Full control (host) front panel USB port
  • Clean air intake, with integrated fans
  • Aluminium digital encoder knob for programming set-points
  • LED indicator of the MagnaLOAD's present regulation state, which can include: constant voltage (CV), constant current (CC), constant power (CP), or constant resistance (CR)
  • Selector buttons to choose which set-point the digital encoder knob and digital keypad buttons will modify.
  • MENU: Enters the menu system on the 4-line display
  • BACK: Moves back one level in the menu
  • ENTER: Selects the highlighted menu item
  • CLEAR: Removes the product from a faulted state
  • LOCK: Locks the front panel, with password protection available


Front Side Dimensions 12.5 kW Models

Rear Side Dimensions 12.5 kW Models

Side Dimensions 12.5 kW Models

Front Side Dimensions 25 kW to 100 kW Models

Rear Side Dimensions 25 kW to 100 kW Models

Bus Bar Dimensions 25 kW to 100 kW Models

How to Buy

For the fastest product and pricing information, please complete the form and the Magna-Power team will address the request immediately.


Magna-Power products are made-to-order with build-times that vary depending on the model's maximum power rating. Current build-time schedules are as follows:

12.5 kW WRx Series Models

8 weeks

25 kW to 100 kW WRx Series Models

14 weeks

Sales Partners

In the USA and Canada, Magna-Power sells it products directly from the factory, with a nationwide network of technical representatives. Magna-Power products are available available worldwide through direct sales offices and authorized distributors. Requests from this form will either be quoted directly or automatically routed to the appropriate sales partner for quote.

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