I need a big resistor to dump reactive energy to. But I need it 'fast' since otherwise the input TVS will overload. The situation: parasitic inductance of wiring makes the whole circuit substantially a huge boost converter and for cost reasons I can't put there a leveling capacitor. For reference, nominal 12V in and I see peaks of 90V. So at the moment the plan is to use the equivalent of a braking resistor and dump the excess (there is a whole water tank to sink, so power dissipation is not an issue).
A good and cheap part would be something like this http://www.arcolresistors.com/resistors/hs25-aluminium-housed-resistor/ they make both inductive and non-inductive parts but, of course, the non-inductive ones are made on paper only these days.
Do you have any experience on the typical inductance of such a wound inductor? even just as a magnitude order, like, about 100nH or 1µH or whatever.
Best Answer
I was asking myself the same question, so I measured some 100 watt power resistors similar to the ones linked in the question with an LCR meter. Here are the results:
There are significant inductance differences between the power resistors. Based on this very limited set of measurements you can guess that lower resistance also means lower inductance for a specific power resistor series. But if a couple of µH series inductance matter in your application, you will have to measure the inductance of the power resistor to be sure.