Datasheet wrx 1 2 1

Série WRx

DC Electronic Load

Key Facts

  • 3 models
  • 12.5 kW power level
  • Up to 1000 Vdc output voltage
  • Up to 130 Adc output current
  • MagnaLINK™ Distributed DSP Architecture
  • 16-bit resolution
  • SCPI programming API
  • CE Mark
  • Designed and manufactured in the USA

Water-Cooled High-Power Electronic Load Using Active Resistance

Models up to 1000 Vdc with Multiple Control Modes for Application Flexibility

The WRx Series MagnaLOAD utilizes Magna-Power's patented Active Resistance Technology (US Patent 9,429,629) in combination with the company’s internally manufactured microchannel water-cooled heatsinks to address high power DC electronic loading 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 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. In addition to the 16-bit precision 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.

Digital Control
Operating Modes
External User I/O
MagnaWEB Software
Active Resistance

MagnaLINK™ Distributed Digital Control

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, digital master-slaving, and many new advanced control technologies.

All ARx Series MagnaLOADs come with the following interfaces:

  • Front panel knob, keypad, and menu system
  • 25-pin configurable external user I/O, including a high-speed analog input
  • Front and rear USB and rear RS-485 or optional Ethernet and IEEE-4888 GPIB

When in standby or diagnostic fault, the DC input bus is disconnected via a switching device.

Finally, with a dedicated +5V interlock input pin and included +5V reference on all models, external emergency stop systems can be easily integrated using an external contact.

WRx Series Digital Control Image

Six Flexible Operating Modes

To accommodate a variety of DC sources, all ARx Series MagnaLOADs come with many configurable control modes, including:

  • Voltage Mode
  • Current Mode
  • Power Mode
  • Resistance Mode
  • Shunt Regulator Mode
  • Rheostat

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 and exceeded by a user-defined percentage, while limiting the shunt current to a programmed set-point.

WRx Series Operating Modes Image

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 integrationand allows control parameters from various interfaces simultaneously.

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

WRx Series External User I/O Image

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 then, using a web browser, access the server connected to the MagnaLOAD from a variety of devices including other desktops, tablets or smart-phones.

WRx Series MagnaWEB Software Image

Active Resistance Technology: A New Era for Electronic Loads

The ARx Series utilizes Active Resistance Technology to deliver performance consistent with conventional electronic loads, but at a fraction of the price and with the ability to directly switch passive resistors on-the-fly.

In Magna-Power's Active Resistive Technology, switched resistors are placed in series with MOSFETs. High-performance DSPs simulatenously control both dissipation elements in harmony. Assuming the power across the shunt resistor is insignificant, the power dissipated in load resistor R1 is IL x VR1 and the power dissipated in MOSFET Q1 is IL x VQ1. The resistors can be operated at higher temperatures than the MOSFETs, simplifying cooling requirements of the passive elements. Keeping VQ1 small and VR1 large lowers system costs in comparison with purely semiconductor electronic loads. Adjusting the value of resistor R1 is accomplished with a binary switching matrix. Finally, keeping the resistor switching increments small and over a wide range maintains the smallest voltages across the linear modules and over the widest operating range.

The advantage of resistive loads are reliability and cost per watt for dissipating power, while the advantage of MOSFET loads is speed of performance and the ability to dissipate power over a wide operating range. Active Resistive Technology blends switched resistance with MOSFETs to significantly lower the product's cost, add new control modes, while still delivering 16-bit precision and high-accuracy performance

WRx Series Active Resistance Image


Choose from 3 WRx Series Models

There are 3 different models in the WRx Series spanning power levels: 12.5 kW.

Use the following ordering guide and models chart to define the best model for your application.

WRx Series Ordering Guide
Model Maximum Power Maximum Voltage Maximum Current Package Type Minimum Voltage
WRx12.5-200-130/UI 12.5 kW 200 Vdc 130 Adc Rack-mount 2.5 Vdc
WRx12.5-500-52/UI 12.5 kW 500 Vdc 52 Adc Rack-mount 3.0 Vdc
WRx12.5-1000-26/UI 12.5 kW 1000 Vdc 26 Adc Rack-mount 5.0 Vdc

Operating Profiles

WRx Series Voltage-Current-Power Operating Range

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.

WRx Series Operating Profile WRx Series Operating Profile


Technical Product Data

AC Input Specifications
AC Input Voltage
1Φ, 2-wire + ground
85 to 265 Vac (UI: Universal Input)
AC Input Frequency
50-60 Hz
AC Input Isolation
±1500 Vac, maximum input voltage to ground
Programming Interface Specifications
Front Panel Programming
Aluminum rotary knob with encoder, keypad, or up-down arrow for single bit control
Computer Interfaces
USB Host (Front): Type B
USB Host (Rear): Type B
RS485 (Rear): RJ-45
MagnaLINK™: RJ-25 x 2
Computer Interfaces
LXI TCP/IP Ethernet (Rear): RJ-45
GPIB (Rear): IEEE-488
External User I/O Port
Analog and Digital Programming
25-pin D-sub DB-25, female
Referenced to Earth ground; isolated from the DC input
See User Manual for pin layout
Programming Specifications
All Modes
16-bit, 0.0015%
Programming and Measurement
Voltage: ±0.1% of full scale voltage rating
Current: ±0.2% of full scale current rating
Power: ±0.3% of full scale power rating
Resistance: ±0.3% of full scale resistance rating
Rise/Fall Time
Voltage Mode: 100 ms, 10% to 90% full scale voltage rating
Current Mode: 2 ms, 10% to 90% full scale current rating
Power Mode: 100 ms, 10% to 90% full scale power rating
Resistance Mode: 40 ms, 10% to 90% full scale resistance rating
Trip Settings Range
Over Voltage: 10% to 110% of full scale voltage rating
Under Voltage: 0% to 110% of full scale voltage rating
Over Current: 10% to 110% of full scale current rating
Over Power: 10% to 110% of full scale power rating
External User I/O Specifications
Digital I/O
Digital Input Voltage: 5V
Digital Input Impedance: 10 kΩ
Digital Monitoring Voltage: 5V, 32 mA capacity
Digital Reference Voltage: 5V, 20 mA capacity
Analog I/O
Analog Sampling Rate: 2 kHz
Analog Programming Voltage: 0-10 V
Analog Programming Resolution: 12-bit, 0.025%
Analog Monitoring Voltage: 0-10 V, 3 mA capacity
Analog Monitoring Impedance: 0.005 Ω
Analog Monitoring Accuracy: 0.05% of full scale
Analog Reference Voltage: 10 V, 20 mA capacity
Physical Specifications
Racking Standard
12.5 kW Models
Rear Support Rails
12.5 kW Models
Size and Weight
12.5 kW Models
7” H x 24” W x 19” D (17.8 x 60.9 x 48.2 cm)
165 lbs (74.8 kg)
Environmental Specifications
Ambient Operating Temperature
0°C to 50°C
Storage Temperature
-25°C to +85°C
Relative humidity up to 95% non-condensing
Air Flow
Front air inlet, rear exhaust
Water Cooling Specifications
Water Connection Provided
12.5 kW Models: 1/2” NPT male inlet and outlet
Maximum Inlet Temperature
Maximum Inlet Pressure
80 PSI
Minimum Flow Rate
12.5 kW Models: 1.5 GPM
Regulatory Compliance
Complies with European EMC Directive for test and measurement products
Complies with EN61010-1
CE Mark
RoHS Compliant


WRx Series Dimensional Drawings

Front Panel
12.5 kW Models
Rear Panel
12.5 kW Models
Side Panel
12.5 kW Models
Front Panel
25 kW to 100 kW Models
Rear Panel
25 kW to 100 kW Models
DC Input Bus
25 kW to 100 kW Models

Options and Accessories

Available for the WRx Series

Hardware Options
Hardware Option Name
Order Code
An integrated IEEE-488 GPIB communications port, allowing the product to be fully controlled and monitored using supported commands, as well as adding some additional interface specific commands.
LXI TCP/IP Ethernet
An integrated TCP/IP Ethernet communications port, certified to the LXI Class C standard, allowing the product to be fully controlled and monitored using supported commands, as well as adding some additional interface specific commands.

Request a Quote

Get WRx Series product pricing

How to Buy

In the USA and Canada, Magna-Power sells it products directly from the factory, with a North American network of technical representatives. Magna-Power products are 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.


Magna-Power products are made-to-order with build-times that vary depending on the model's maximum power rating. The current build-time for the WRx Series is 6 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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