Steep Front Impulse Wave Device
Impulse Charging Resistors: Purpose, Selection & Applications in High-Voltage Testing
In high-voltage impulse testing systems, charging resistors play a critical role in safely energizing pulse capacitors. This article explains their function, design considerations, and practical applications.
What Are Impulse Charging Resistors?
Impulse charging resistors are high-power resistive components used to:
Limit inrush current during capacitor charging
Prevent damage to DC power supplies
Control charging time constants
Improve system safety during high-voltage tests
Key Design Parameters
When selecting charging resistors for impulse generators, consider:
| Parameter | Consideration |
|---|---|
| Resistance Value | Typically 10kΩ to 100kΩ (determines charging time) |
| Power Rating | Must withstand continuous charging current (often 100W-1kW) |
| Voltage Rating | Should exceed maximum charging voltage (e.g., 50kV-200kV) |
| Inductance | Low-inductance designs prevent waveform distortion |
Circuit Configuration
In a typical Marx generator or impulse test system:
Resistors are connected in series with the charging supply
Multiple resistors may be stacked for high-voltage applications
Parallel resistor-capacitor networks ensure uniform voltage distribution
Application Examples
Lightning Impulse Generators: Charging resistors control the 1.2/50µs waveform formation
Partial Discharge Test Systems: Enable controlled capacitor charging for sensitive measurements
High-Power Pulse Systems: Protect components from excessive inrush currents
Maintenance & Safety
Best practices include:
Regular inspection for thermal damage or arcing
Verification of resistance values (tolerance typically ±5%)
Use of properly rated HV connectors and insulation
Conclusion
Properly specified impulse charging resistors are essential for reliable, repeatable high-voltage testing. Their selection impacts both system safety and test accuracy in applications ranging from insulator testing to power equipment validation.
