Static and dynamic loading
CC, CP and CR, together with CCD, CPD and CRD, provide constant and time-varying loads for DC power supplies.
N65500 – Regenerative High-Speed DC Load Rated at 20 or 25 kW
For fast EDPP load profiles and dynamic server power supply testing with energy regeneration.
The N65500 combines fast load transitions and regenerative power testing in one instrument. Designed for testing high-power DC supplies, this regenerative electronic load combines programmable current slew rates with the return of absorbed energy to the AC supply grid.
Short-term power headroom
Depending on the model, up to 32 kW or 40 kW is available for 30 seconds; rated power is 20 or 25 kW.
Programmable load profiles
Sequence, EDPP and sweep functions support repeatable tests with defined load levels, slew rates and timing.
Test system integration
LAN, USB, CAN, RS232 and RS485, together with SCPI, MODBUS-RTU and CAN-Open, support integration into automated test processes.
Personal project consultation
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Select the appropriate technical configuration or access product documentation directly.
ART. NO.
Description
Current [A]
Power [P]
Voltage [V]
N65520-80-600
|
Description
N65520-80-600 High-Speed Regenerative DC Electronic Load, 20 kW / 32 kW peak (30 s), 80 V, 600 A, current slew rate up to 60 A/µs, regenerative efficiency up to 91%, 6U
|
Current [A]
600
|
Power [P]
20000
|
Voltage [V]
80
|
High-Speed Regenerative DC Electronic Load
N65525-1000-80
|
Description
N65525-1000-80 High-Speed Regenerative DC Electronic Load, 25 kW / 40 kW peak (30 s), 1000 V, 80 A, current slew rate up to 8 A/µs, regenerative efficiency up to 94%, 6U
|
Current [A]
80
|
Power [P]
25000
|
Voltage [V]
1000
|
High-Speed Regenerative DC Electronic Load
N65500 regenerative DC electronic load overview
The N65500 series is a regenerative DC electronic load for development and production testing of high-power supplies. It absorbs energy from the DC output of the device under test and returns part of that energy to the AC supply grid. This reduces the heat that must be removed from the test environment compared with a purely dissipative load. Two versions address different operating points: the N65520-80-600 rated at 80 V, 600 A and 20 kW, and the N65525-1000-80 rated at 1,000 V, 80 A and 25 kW. Both individual units occupy 6U. Constant current, constant power and constant resistance operation are complemented by dynamic load functions. Applications include server power supplies, AIDC power modules and DC charging station modules. Voltage, current, continuous power and the time profile of the load must be considered together when selecting a unit.
Key benefits
Reduced heat dissipation
Regeneration returns absorbed energy to the supply grid. A regenerated energy display supports assessment of energy use during testing.
Power within limited space
Rated power of 20 kW or 25 kW in 6U supports high-power test stations where installation space is limited.
Identify critical frequencies
Dynamic sweep captures maximum and minimum voltage and their corresponding frequency points, helping identify areas that require closer analysis of power supply dynamics.
Reproduce load peaks
EDPP tests reproduce rapid transitions between load levels, supporting verification of power delivery by AIDC power supplies.
Fine current adjustment
CC setting resolution is 10 mA for the 600 A model and 1 mA for the 80 A model, allowing fine setpoint increments within each range.
Evaluate DUT protection
OCP and OPP test functions support evaluation of the overcurrent and overpower behaviour of power supplies.
Operating principle and load control
CC operation controls the absorbed current. In CP operation, current adapts to the input voltage to absorb the selected power; CR operation applies a selected resistance characteristic. CR+CC and CP+CC are also available as combined modes. The regenerative architecture combines these load functions with energy return to the AC grid.
Models and power range
| Model | Max. DC voltage | Max. DC current | Rated power | Height |
|---|---|---|---|---|
| N65520-80-600 | 80 V | 600 A | 20 kW | 6U |
| N65525-1000-80 | 1,000 V | 80 A | 25 kW | 6U |
Size the operating point: P = U × I applies. At rated power and for U > 0, current is limited by I ≤ min(I-rated, P-rated/U); the permitted operating limits also apply. At 80 V, 20 kW corresponds to 250 A; at 1,000 V, 25 kW corresponds to 25 A. Rated voltage and maximum current therefore cannot be used simultaneously at rated power.
Short-term overload
| Time-limited load power | N65520-80-600 | N65525-1000-80 |
|---|---|---|
| 120% for 300 s | 24 kW | 30 kW |
| 140% for 60 s | 28 kW | 35 kW |
| 160% for 30 s | 32 kW | 40 kW |
Overload ratings are time-limited and do not represent higher continuous power. Voltage and current limits must also be considered when specifying load peaks.
Dynamics and sweep
Rise and fall slew rates, high and low load levels, dwell times and cycle count can be configured for dynamic loading. Maximum current slew rate is 60 A/µs for the N65520-80-600 and 8 A/µs for the N65525-1000-80. Each CCD interval, T1 and T2, can be set from 25 µs to 3,600 s.
In dynamic sweep mode, voltage and current are sampled at 500 kHz. Load current frequency can be varied up to 30 kHz, with Vpk+, Vpk− and their corresponding frequency points recorded. Sampling rate, sweep frequency and current slew rate describe different properties and must be evaluated separately for the test profile.
Operating modes and programmable functions
| Function | Operation and benefit |
|---|---|
| CC / CP / CR | Constant current, power or resistance settings for steady-state loading of a DC source. |
| CR+CC / CP+CC | Combined modes for load conditions with resistance or power and current components. |
| CCD / CRD / CPD | Dynamic current, resistance and power loading to investigate time-dependent responses. |
| Dynamic load / sequence | Programmable load levels and timing for recurring test profiles. |
| EDPP | Fast load transitions for testing short-term power delivery by AIDC power supplies. |
| OCP / OPP | Testing the overcurrent and overpower behaviour of the DUT. |
Typical applications
Server power supplies and power shelves
Dynamic load profiles, EDPP and sweep support characterisation of load transient response and stability in high-power server supplies.
DC charging station modules
The DC output of a charging module is tested with defined current, power or resistance loading. Model selection depends on output voltage, current and required load power.
Production testing and burn-in
AIDC power modules can undergo high-power loading and dynamic testing. Regeneration and sequence functions support recurring production processes.
Interfaces and automation
| Feature | Role |
|---|---|
| LAN, USB, CAN, RS232, RS485 | Communication interfaces for integration into higher-level test systems. |
| SCPI, MODBUS-RTU, CAN-Open | Supported communication protocols; the specific assignment to interfaces should be agreed during integration. |
| Display, numeric keys, function keys, rotary knob | Local operation and adjustment on the instrument. |
| Regenerated energy measurement | Display of regenerated energy and regeneration efficiency for observing test operation. |
Parallel operation
The series supports expansion through parallel operation. Unit count, combination, achievable dynamics and system power must be agreed for the specific configuration.
Installation and infrastructure
| Parameter | Configuration / range |
|---|---|
| AC supply | Three-phase four-wire supply, 340–480 V AC |
| Grid frequency | 47–63 Hz |
| Power factor | ≥ 0.99 |
| Height / net weight | 6U; approximately 75 kg per unit |
| Operating temperature | 0–40 °C |
| Storage temperature | −20 to +70 °C |
| Environment | Altitude < 2,000 m; relative humidity ≤ 80%, non-condensing |
Protection functions
Protection and monitoring functions cover overvoltage and undervoltage, overcurrent and undercurrent, overpower and overtemperature, together with a reverse polarity alarm. OCP/OPP functions for testing the DUT are distinct from these instrument protection functions.
Frequently asked questions
Which version suits my DUT?
The N65520-80-600 addresses low-voltage, high-current operation, while the N65525-1000-80 covers higher DC voltages. Simultaneous voltage, current and power requirements, together with the load profile, determine the choice.
Is continuous operation at 600 A and 80 V possible?
This combination equals 48 kW and exceeds the 20 kW rating. At 80 V, the current limit calculated from rated power is 250 A; other operating limits also apply.
Can the load absorb 160% continuously?
No. The 160% rating corresponds to 32 kW or 40 kW for 30 s. Continuous power is 20 kW or 25 kW, depending on the model.
What current slew rate is available?
Up to 60 A/µs for the N65520-80-600 and up to 8 A/µs for the N65525-1000-80. These values describe current change per unit time, not sweep frequency.
What does dynamic sweep show?
It captures maximum and minimum voltage and the frequency points at which they occur, enabling investigation of critical regions in dynamic power supply behaviour.
Can server power supplies be tested with EDPP profiles?
Yes. EDPP and dynamic load functions support rapid transitions between load levels. Profiles must remain within the load’s voltage, current and time-dependent power limits.
Is the N65500 suitable for DC charging station modules?
Yes. It loads the module’s DC output using CC, CP or CR. The model is selected according to the required operating point and load dynamics.
Can it be used for burn-in and production testing?
Yes. The series supports high-power burn-in and dynamic testing of AIDC power modules. Sequences and communication interfaces enable recurring test processes.
Technical consultation and project enquiry
To select an N65500, provide your DUT voltage range, maximum current, continuous and peak power, peak duration and required current slew rate. Include details of the test sequence, interfaces and available AC supply infrastructure.
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