HPP series High Pulse Power resistors – up to 54 joules
Riedon developed the HPP series resistors to offer higher pulse performance when compared to generic off-the-shelf versions. The joule ratings listed for this series are not the highest energy rating we can produce for each version, but do give an indication of the overall capabilities available for different physical sizes and resistance value options. The HPP is currently offered in three, five, or ten-watt variants with resistance values from 10 ohms to 20K ohms and energy dissipation up to 54 joules.
How Riedon optimizes for pulse performance
In general, we prefer to work with our customers to meet the necessary energy dissipating requirements. We then use optimized materials and manufacturing techniques to meet the desired rating. When determining the pulse rating, we assume the resistance wire will absorb all of the pulse (true for short duration pulses) and then size the resistance wire accordingly to provide for a very comfortable safety margin. Part of the calibration process for wire wound resistors removes some material from the winding to bring the part within tolerance. This material removal has the potential to create hot-spots in pulse applications, and is consequently not ideal. Therefore, we recommend sticking with a 5% tolerance for pulse applications as we can easily wind a part to that tolerance and thus avoid material removal. If necessary, we can supply parts with a tolerance as tight as 2% without mechanical calibration.
Application examples for High Pulse Power resistors
The HPP series capitalizes on this know-how to provide options with improved pulse performance, high power density, and low TCR in a rugged vibration and flame-resistant package. Common applications include: defibrillators, capacitor charge/discharge circuits, surge current protection, snubbers, power factor control, and lightning strike suppression.