How do Riedon resistors handle an extreme pulse?
Riedon was recently contacted by an industrial controls company seeking a solution for a pulse requirement in one of their new products. During normal operation the resistors need to absorb around 100 joules of energy each. To meet this requirement, we developed a pulse rated part based on our UTN-7A 100 OHM 5% (SPxxxx). Note that this resistor is rated for 7 watts
The customer performs a specific test that simulates a short circuit condition. The criteria for the short circuit test are that two of the resistors connected in series withstand a 24-amp pulse for five seconds. This calculates to 115,200 watts!
The video shows the results of this test. The two resistors are located center screen. Note that around the sixteen second mark the UL 94V-0 rated coating does catch fire, but immediately extinguishes as expected. Customer advises that after the test, the resistors still met electrical specifications (i.e. 100 ohms +/- 5%).
Clearly, this is an extreme example. It does, however, illustrate the pulse withstanding capabilities of our product line as well as the overall robustness of the assembled component. It is also an excellent example of how ideally suited to pulse applications wire wound resistors are. More information on the advantages of wire wound resistors may be found here:
Do you have any tough to solve resistor requirements we can assist with?