RMX-4124 1500 W 30 V 150 A Programmable DC Power Supply
The RMX-4124 is a single-channel, 1500 W programmable DC power supply designed for high-current validation, power-electronics development, production testing and laboratory automation. Its autoranging output architecture supports flexible voltage and current operating points with rated capabilities up to 30 VDC or 150 A.
The RMX-4124 provides twice the output power and current capability of the RMX-4120 while retaining a compact, full-width 1U rack-mount format. Engineers can operate the supply through its front-panel controls or automate it using LAN, USB, RS232 and external analog interfaces.
Key Features of the RMX-4124
- 1500 W maximum output power
- 30 V rated output voltage
- 150 A rated output current
- Flexible autoranging output architecture
- 0 V to 31.5 V programmable voltage range
- 0 A to 157.5 A programmable current range
- Single programmable DC output channel
- Constant-voltage and constant-current operation
- Four-wire remote sensing
- Up to 1.5 V remote-sense compensation per line
- 1 ms or less voltage transient response
- Programmable overvoltage protection
- Programmable overcurrent protection
- Programmable undervoltage limit
- Three front-panel preset memories
- LAN, USB and RS232 communication
- External analog programming and monitoring
- Parallel operation with up to four identical units
- Series operation with up to two identical units
- Compact 1U full-width rack-mount design
RMX-4124 Technical Specifications
| Product Model | RMX-4124 |
|---|---|
| Part Number | 784765-01 |
| Product Type | High-current programmable rack-mount DC power supply |
| Number of Output Channels | 1 |
| Rated Output Power | 1500 W |
| Rated Output Voltage | 30 VDC |
| Rated Output Current | 150 A |
| Voltage Setting Range | 0 V to 31.5 V |
| Current Setting Range | 0 A to 157.5 A |
| Voltage Setting Accuracy | ±(0.05% of setting + 0.05% of rated voltage) |
| Current Setting Accuracy | ±(0.5% of setting + 0.1% of rated current), from 1% to 100% of rated current |
| Voltage Line Regulation | ±5 mV |
| Voltage Load Regulation | ±5 mV |
| Current Line Regulation | ±17 mA |
| Current Load Regulation | ±35 mA |
| Voltage Transient Response | 1 ms or less under specified load-change conditions |
| Voltage Ripple and Noise | 60 mV peak-to-peak; 8 mV RMS |
| Current Ripple and Noise | 300 mA RMS under specified conditions |
| Voltage Rise Time | 100 ms |
| Voltage Fall Time | 100 ms at rated load; 1000 ms at no load with bleeder enabled |
| Remote-Sense Compensation | Up to 1.5 V per output line |
| Overvoltage Protection Range | 3 V to 33.6 V |
| Fixed Secondary Overvoltage Protection | 36 V |
| Overcurrent Protection Range | 15 A to 168 A |
| Undervoltage Limit Range | 0 V to 31.5 V |
| AC Input Rating | 100 VAC to 240 VAC, 50 Hz to 60 Hz, single phase |
| AC Input Voltage Range | 85 VAC to 265 VAC |
| AC Input Frequency Range | 47 Hz to 63 Hz |
| Maximum AC Input Current | 21 A at 100 VAC; 10.5 A at 200 VAC |
| Maximum AC Input Power | 2200 VA at 100 VAC |
| Minimum Efficiency | 74% at rated load |
| Minimum Power-Interruption Hold-Up | 20 ms |
| LAN Interface | 10Base-T or 100Base-TX Ethernet, IPv4 |
| Additional Interfaces | USB, RS232 and analog control |
| Parallel Operation | Up to four identical units including the master |
| Series Operation | Up to two identical units |
| Preset Memory | Three groups of output and protection settings |
| Output-to-Ground Isolation | ±250 V maximum |
| Rack Size | 1U, full rack width |
| Weight | Approximately 9.5 kg |
| Cooling Method | Forced-air fan cooling |
| Operating Temperature | 0°C to 50°C |
| Operating Humidity | 20% to 85% RH, noncondensing |
| Maximum Altitude | 2,000 m |
RMX-4124 Part Number and Included Items
| Item | Part Number | Description |
|---|---|---|
| RMX-4124 | 784765-01 | 1500 W, 30 V, 150 A single-channel programmable DC power supply |
| Power Supply | Included | One full-width 1U RMX-4124 power supply |
| Output Terminal Hardware | Included with instrument | M8 output connection hardware and protective terminal cover |
| Safety Documentation | Included | Safety, environmental and regulatory documentation |
| AC Input Cable | User supplied | Facility-specific cable for connection to a dedicated switchboard circuit |
The RMX-4124 does not use an ordinary removable IEC power cord. Its high-power AC input must be connected to an appropriate facility circuit by qualified personnel using the required cable, grounding and dedicated protective breaker.
1500 W Autoranging Output
The RMX-4124 can operate across a broad combination of voltage and current values while limiting total output power to 1500 W. Its autoranging architecture provides more usable operating points than a conventional fixed-range supply.
The rated 30 V and 150 A limits cannot be delivered simultaneously because that operating point would require 4500 W. At 30 V, the available output current is approximately 50 A. At 150 A, the available output voltage is approximately 10 V.
Calculate each required DUT operating point and confirm that the product of voltage and current does not exceed 1500 W.
30 V Rated Output Voltage
The RMX-4124 has a rated output voltage of 30 V and a programmable setting range extending to 31.5 V. This range supports 5 V, 12 V, 24 V and 28 V electronic systems.
Its high-current capability makes it suitable for computing hardware, telecommunications equipment, vehicle electronics, power converters and industrial devices that require substantially more power than standard benchtop supplies can provide.
150 A Rated Output Current
The RMX-4124 delivers rated output current up to 150 A, with a programmable setting range extending to 157.5 A. It is the highest-current model in the corresponding RMX-412x programmable power-supply family.
At 150 A, even very small cable and connector resistance can produce significant heat and voltage drop. Output wiring must be designed as part of the complete power-delivery system rather than treated as an ordinary test lead.
High-Current Cable Selection
Use load cables with sufficient current capacity and insulation rated for the application. Cable temperature depends on conductor resistance, ambient temperature, insulation rating, bundling and available airflow.
NI’s reference table indicates that 1/0 AWG cable has an approximate cross-sectional area of 53.49 mm² and an allowable current of 190 A under the stated reference conditions. Actual cable selection must account for the installation environment and applicable electrical standards.
Keep the positive and negative conductors close together to reduce output noise, but consider the thermal effect of bundling. Use insulation with heat resistance of at least 85°C around the output connection area.
M8 Output Connections
The RMX-4124 uses high-current M8 bolted output terminals. Appropriate ring terminals should be crimped using tooling intended for the selected conductor size.
Incorrectly crimped, loose or contaminated terminals can develop high resistance and dangerous heat. Tighten the connections according to the applicable installation instructions and install the output terminal cover before energizing the supply.
Dedicated AC Input Installation
The 1500 W RMX-4124 requires a direct connection to an appropriate AC circuit. NI specifies a nominal single-phase input of 100 VAC to 240 VAC and an accepted range of 85 VAC to 265 VAC.
The maximum input current is 21 A at 100 VAC and 10.5 A at 200 VAC. Installation requires a dedicated breaker with a rating not exceeding 30 A and wiring that complies with local electrical regulations.
The AC connection must be completed by a person with the necessary electrical knowledge. The circuit breaker must remain accessible and clearly identified as the RMX-4124 disconnecting device.
AC Input Cable Requirements
The official installation guidance specifies a three-core input cable with a nominal conductor area of 5.5 mm², a finished outside diameter between 10.5 mm and 14.4 mm, a rating of at least 250 V and a maximum length of 3 m.
The line, neutral and protective-ground conductors must be connected to their corresponding terminals. Protective earth must never be omitted.
Constant-Voltage Operation
In constant-voltage mode, the RMX-4124 regulates the programmed voltage while allowing current to flow up to the configured current setting. The front-panel CV indicator identifies voltage-regulation operation.
If the load attempts to draw more than the programmed current, the supply transitions into constant-current mode instead of maintaining the requested voltage.
Constant-Current Operation
In constant-current mode, the RMX-4124 regulates the programmed output current while allowing voltage to change according to the connected load. The programmed voltage setting limits the maximum output voltage.
This mode supports high-current component testing, conductor testing, controlled device conditioning and other applications that require a regulated current stimulus.
Four-Wire Remote Sensing
The RMX-4124 supports remote sensing to compensate for voltage drop in high-current output cables. Separate low-current sense conductors measure voltage directly at the DUT terminals.
The supply can compensate for up to 1.5 V of drop on each output line. This capability is valuable at high current because even milliohms of cable resistance can produce a measurable voltage error.
The supply remains subject to its 31.5 V setting range and 1500 W power limit. Remote sensing does not permit operation beyond the maximum output-terminal rating.
Remote-Sense Wiring
Use twisted-pair or shielded conductors for the sense connections and connect them directly to the DUT terminals. Keep sense wiring away from switching nodes and high-current magnetic fields where possible.
Incorrect polarity or disconnected sense wiring can cause unstable output. Inspect the sensing circuit before enabling a high-current test.
Fast Transient Response
The RMX-4124 provides voltage transient response of 1 ms or less under the specified load-change conditions. This allows the output to recover rapidly when a DUT transitions between operating states.
Actual dynamic performance depends on output-cable inductance, load behavior, remote-sense connections and external capacitance. Verify performance using the intended DUT and production fixture.
Low Voltage Line and Load Regulation
The RMX-4124 specifies voltage line regulation and load regulation of ±5 mV. These characteristics help maintain stable output as the AC supply or connected load changes.
For the best regulation at the DUT, combine remote sensing with low-resistance power conductors and correctly routed sense wiring.
Programmable Overvoltage Protection
The primary overvoltage protection threshold can be configured between 3 V and 33.6 V. When the threshold is exceeded, the RMX-4124 disables the output, displays OVP and activates the alarm indicator.
A secondary fixed overvoltage protection threshold is set at 36 V. Set the primary OVP threshold below the maximum safe input voltage of the DUT.
Programmable Overcurrent Protection
The overcurrent protection threshold can be configured between 15 A and 168 A. When OCP activates, the output is disabled and the instrument reports an alarm.
OCP is a shutdown function and is separate from normal constant-current regulation. It does not protect against every short-duration discharge-current peak from internal or external capacitors.
Undervoltage Limit
The programmable undervoltage limit prevents the output from being set below a defined value. The RMX-4124 UVL range extends from 0 V to 31.5 V.
This feature can prevent devices from being operated in an unsuitable low-voltage condition that could cause instability or excessive current.
Three Preset Memories
The RMX-4124 can store three groups of commonly used voltage, current, OVP, OCP and UVL values. Presets help operators switch between known DUT configurations with fewer manual adjustments.
The front-panel PRESET indicators show which stored configuration is active.
LAN Remote Control
The LAN interface supports 10Base-T and 100Base-TX Ethernet communication over IPv4 through an RJ45 connector. It is suitable for rack-mounted production systems and remotely controlled laboratories.
Configure the IP address, subnet and communication parameters before connecting the application. Network security settings must allow communication between the controller and power supply.
USB Connectivity
The USB interface provides a direct connection to a nearby computer for instrument setup, benchtop development and automated control.
Install the required communication software and driver before connecting the instrument. Verify that the RMX-4124 appears as a valid VISA resource.
RS232 Communication
The RS232 interface supports industrial computers, embedded controllers and established test systems that rely on serial communication.
Verify that the controller and power supply use matching baud rate, data format and command-termination settings.
External Analog Control
The analog-control interface allows external voltage or resistance signals to program the RMX-4124. Analog monitor signals can represent output voltage, current and operating status.
This interface is useful for real-time control, hardware-in-the-loop testing and systems in which output control must follow another hardware signal.
Parallel Operation
Up to four identical RMX-4124 units, including the master, can be configured for supported master-slave parallel operation. A four-unit system can provide substantially more current and power than one supply.
A theoretically combined system may reach as much as 6000 W and 600 A within its permitted operating area. Such a system requires specialized bus bars, protection, facility power and thermal design.
Series Operation
Up to two identical RMX-4124 units can be operated in series to increase the available output voltage. The system must remain within the ±250 V output-to-ground isolation rating.
Review grounding, remote-sense wiring and protection before connecting supplies in series. Never connect series outputs in a way that exceeds the insulation rating of the DUT or fixture.
Typical RMX-4124 Applications
- Automotive electronics testing
- Electric-vehicle component validation
- High-current DC-DC converter testing
- Computing and server hardware testing
- Telecommunications equipment validation
- Power-distribution unit testing
- Industrial controller validation
- Bus-bar and conductor testing
- Battery-powered device simulation
- Fuel-cell support-system testing
- Electronic component conditioning
- Production functional testing
- Burn-in and reliability testing
- Rack-mounted automated test equipment
Automotive and Electric-Vehicle Testing
The 30 V range supports many 12 V, 24 V and 28 V automotive and commercial-vehicle components. High current is useful for controllers, lighting systems, power-distribution modules and low-voltage electric-vehicle subsystems.
Fast automotive surge and dropout waveforms may require additional transient-generation equipment. Confirm the waveform, rise-time and energy requirements before system design.
High-Current Converter Testing
The RMX-4124 can supply input power to high-current DC-DC converters and voltage-regulator assemblies. Automated software can sweep the input voltage and evaluate efficiency, regulation, thermal behavior and protection thresholds.
A programmable electronic load connected to the converter output can complete the automated source-and-load test system.
Computer and Server Hardware Testing
The 150 A capability supports low-voltage computing, server and telecommunications assemblies with substantial power demand. Programmable current limits help protect prototypes during initial power-up.
Large input capacitors can cause significant inrush current. Configure appropriate limits and evaluate whether the startup profile fits within the RMX-4124 power envelope.
Bus-Bar and Conductor Testing
The supply can provide controlled high current for evaluating voltage drop, connection resistance and thermal behavior of bus bars, fuses, connectors and conductors.
The RMX-4124 is not a precision micro-ohmmeter. Use appropriate measurement instruments and Kelvin connections when calculating low resistance from applied current and measured voltage.
Burn-In and Reliability Testing
The RMX-4124 can continuously power electronic devices during burn-in, environmental and reliability testing. LAN and other remote interfaces allow the output and alarm state to be monitored by automated software.
For continuous high-power operation, maintain unobstructed airflow and verify that the AC circuit, output wiring and fixture terminals are rated for the load.
Calibration and Warm-Up
The RMX-4124 ships with a calibration utility. Official performance specifications assume a 30-minute warm-up with current flowing and calibration in a 23°C ±5°C environment.
Calibration intervals should follow NI recommendations and the organization’s quality, usage and uncertainty requirements.
RMX-4124 Troubleshooting
The RMX-4124 cannot output 30 V at 150 A
The voltage and current ratings cannot be delivered simultaneously because the output is limited to 1500 W. At 30 V, the maximum current is approximately 50 A. At 150 A, the maximum voltage is approximately 10 V.
The RMX-4124 does not power on
Confirm that the dedicated AC circuit, breaker, line, neutral and protective-ground connections are correct. Input installation should only be inspected or modified by qualified personnel.
The output voltage is lower than programmed
Check whether the supply has entered constant-current mode or reached its 1500 W power limit. Inspect the high-current cables and remote-sense wiring for excessive voltage drop.
The output terminals or cables become hot
Stop the test immediately. Inspect conductor size, crimp quality, contact cleanliness, terminal torque and cable bundling. Replace any component not rated for the continuous current.
The remote-sense output is unstable
Check sense polarity, shielding and routing. Keep the sense circuit away from high-current magnetic fields and electrically noisy switching conductors.
The RMX-4124 reports OVP
Verify that the OVP threshold is above the intended voltage but below the DUT’s safe maximum. Inspect the sense wiring and check for voltage applied by another source.
The RMX-4124 reports OCP
Check for a short circuit, excessive inrush current or an incorrectly configured threshold. OCP shuts down the output and is separate from normal current regulation.
The power-limit indicator is active
The requested voltage and load current exceed 1500 W. Reduce the voltage, reduce the required current or use additional supplies in an approved configuration.
The LAN connection does not work
Confirm the IP address, subnet, Ethernet cable and link status. Verify that firewall or network-security settings allow communication with the instrument.
The unit shuts down during continuous operation
Review the alarm message, AC input, rack airflow, fan operation and ambient temperature. Ensure that neither the front nor rear ventilation openings are obstructed.
RMX-4124 Comparison with Similar Programmable Power Supplies
| Model | Rated Output | Power | Best Suited For |
|---|---|---|---|
| RMX-4120 | 30 V, 75 A | 750 W | Lower-power, high-current testing |
| RMX-4124 | 30 V, 150 A | 1500 W | Low-voltage, very-high-current testing |
| RMX-4125 | 80 V, 56 A | 1500 W | Medium-voltage power electronics |
| RMX-4126 | 230 V, 20 A | 1500 W | High-voltage converters and industrial devices |
| RMX-4127 | 650 V, 7 A | 1500 W | Very-high-voltage device testing |
| RMX-4104 | Up to 100 V or 40 A, depending on version | Up to 864 W | Fixed-range high-power rack systems |
RMX-4124 vs RMX-4120
The RMX-4120 and RMX-4124 both provide rated voltage up to 30 V. The RMX-4124 doubles the maximum output power from 750 W to 1500 W and doubles rated current from 75 A to 150 A.
Select the RMX-4120 when 750 W is sufficient and a conventional IEC input connection is preferred. Select the RMX-4124 when the DUT requires more current or power and the facility can support its dedicated AC installation.
RMX-4124 vs RMX-4125
The RMX-4124 is optimized for low-voltage, very-high-current operation up to 30 V and 150 A. The RMX-4125 extends the rated voltage to 80 V while reducing rated current to 56 A.
Choose the RMX-4124 for 12 V, 24 V and other high-current low-voltage devices. Choose the RMX-4125 when the application requires voltage above 30 V.
RMX-4124 vs RMX-4104
The RMX-4104 provides up to 864 W and is available in several fixed voltage and current configurations. The RMX-4124 provides 1500 W autoranging output and reaches 150 A.
Select the RMX-4104 for lower-power systems that match one of its fixed configurations. Select the RMX-4124 for flexible, very-high-current test requirements.
Recommended Related Products
- RMX-4120 750 W 30 V 75 A Programmable Power Supply
- RMX-4125 1500 W 80 V Programmable Power Supply
- RMX-4126 1500 W 230 V Programmable Power Supply
- RMX-4127 1500 W 650 V Programmable Power Supply
- RMX-4104 High-Power Programmable DC Power Supply
- PXI-4130 40 W Source Measure Unit
- View More NI PXI and PXI Express Modules
Selecting the Right RMX Power Supply
Choose the RMX-4124 when the application requires up to 150 A, operates at 30 V or below and needs as much as 1500 W. It is particularly suitable for high-current converters, vehicle electronics, computing equipment and power-distribution components.
Select the RMX-4120 when 750 W is sufficient. Choose the RMX-4125, RMX-4126 or RMX-4127 when the application requires higher voltage.
Why Choose the RMX-4124?
- Provides 1500 W from one programmable output
- Supports current up to 150 A
- Supports voltage up to 30 VDC
- Offers flexible autoranging operation
- Provides 1 ms or less transient response
- Compensates cable voltage drop through remote sensing
- Includes programmable OVP, OCP and UVL protection
- Supports LAN, USB, RS232 and analog control
- Supports series and parallel multidevice operation
- Occupies only 1U of rack height
Frequently Asked Questions
What is the RMX-4124?
The RMX-4124 is a single-channel, 1500 W autoranging programmable DC power supply with rated output capability up to 30 V or 150 A.
Can the RMX-4124 output 30 V and 150 A simultaneously?
No. That operating point would require 4500 W. Voltage and current combinations are limited to a maximum output power of 1500 W.
What is the voltage setting range?
The programmable voltage range is 0 V to 31.5 V. The rated output voltage is 30 V.
What is the current setting range?
The programmable current range is 0 A to 157.5 A. The rated output current is 150 A.
Does the RMX–4124 use a standard IEC power cord?
No. The 1500 W RMX-4124 requires a suitable facility power cable connected to a dedicated circuit and protective breaker by qualified personnel.
Does the RMX-4124 support remote sensing?
Yes. Its remote-sense terminals can compensate for up to 1.5 V of voltage drop on each output line.
Can multiple RMX-4124 units be connected in parallel?
Yes. Up to four identical RMX-4124 units, including the master, can be used in a supported parallel configuration.
Can RMX-4124 units be connected in series?
Yes. Up to two identical units can be used in a supported series configuration, subject to grounding and isolation limits.
Which communication interfaces are available?
The RMX-4124 supports LAN, USB, RS232 and external analog control.
What is the RMX-4124 part number?
The standard NI part number for the RMX-4124 is 784765-01.
Request a Quote for the RMX-4124
Contact us for current availability, lead time and project pricing for the RMX-4124 1500 W 30 V 150 A Programmable DC Power Supply. We can also help identify the required high-current output cables, crimp terminals, rack accessories and related RMX power supplies for your automated test system.
