I am on a learning curve to gain updated knowledge of 1.5 kV MOSFETs and IGBTs and their drivers, flyback transformers and the many ways of generating and switching high voltages.

My question is what kind of general purpose loads should I be building for my experimentation?

Do I buy a bag of 1 and 10 ohm wire wound high wattage resistors, to lash up into a suitable frame to test my 1.5 kV 60 A IGBT. Do I have to build a snubber for these loads?

And how does one load a flyback transformer as they normally plug into a CRT which is a capacitor from the circuit's point of view.

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    \$\begingroup\$ Do you realize you can easily kill yourself, with these experiments? \$\endgroup\$ May 26 '18 at 15:23
  • \$\begingroup\$ Yes. I do. I working in carriers in my youth. Which is where hundreds of telephone calls had their frequency altered to be mixed into a microwave feed. We had to work with one hand in our pocket. I have also build my own earth rail by embedding four three meter steel tubes in the ground. I don't want a neon transformer arcing into the house earth that may have baths and basins earthed to it. \$\endgroup\$
    – kingchris
    May 27 '18 at 5:39
  • \$\begingroup\$ @analogsystemsrf And anyone in the room. With these powers the parts can become fragmentation grenades. \$\endgroup\$
    – Jeroen3
    May 29 '18 at 8:42
  • \$\begingroup\$ Reactive loads with WW and stray capacitance is likely to cause unwanted resonance. \$\endgroup\$ Jun 5 '18 at 0:07
  • \$\begingroup\$ Ok. Then I shall have to learn about snubbers or filters to limit any ringing etc. \$\endgroup\$
    – kingchris
    Jun 5 '18 at 6:08

For a start, I suggest you acquire an adjustable electronic load for this project (example). It will have various protection features you'll not figure out when building a dummy load yourself.

In later stages of your project (when you're confident that your device works in principle), you'll do exactly what you said: bundle a bunch of resistors, caps and a few fans into a case, and use that as a test load.

Remember that working with kV voltages requires precautions. Put a discharge circuit on every cap that may get charged to high voltage, and acquire a safety voltage detector which you would use every time before you touch your device after a test.

  • \$\begingroup\$ Thanks. Looks expensive. But if it saves my heart. Worth it. \$\endgroup\$
    – kingchris
    May 29 '18 at 15:14
  • \$\begingroup\$ @kingchris Yes, those are pricey for a hobbyist. I see those in a professional setting, where such a must-have device for ~10-20% of what a good scope costs doesn't look expensive at all. Unfortunately, I doubt you can find a cheaper hobby-grade device rated at 1kV. \$\endgroup\$ May 30 '18 at 7:23
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    \$\begingroup\$ No, I will use some of this learning for professional usage. It is like an audio amp. If you are going to run it at 60 watts most of the time. Buy a 100 watts app. Most of the distortion and clipping occurs when you run something near to 100% of its capabilities. So if I have to switch 1kv, build a circuit rated at 1.5kv. More expensive but less trouble long term. I do design work where a solution gets build and sold into deepest darkest Africa where you want your creation to work under difficult conditions and not fail for three years. So time to get a deposit and buy a load tester. \$\endgroup\$
    – kingchris
    Jun 1 '18 at 13:20

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