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What, if any, problems would arise when using motor run capacitors in circuits operating in higher frequency ranges? Such as 2000 to 10,000 Hz or 10 to 100KHz

As they are only intended to run in 60Hz applications, I'm wondering if internal resistance would become noticeable and cause excessive heating or if some other potential issue will arise. What is the range of internal inductance on a motor run capacitor? That would surely be more noticeable at higher frequencies.

I'm considering such capacitors for my application because of their large capacitance and modest voltages at a low price point.

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    \$\begingroup\$ Most capacitors are limited by dV/dt and a motor start capacitor does not have to handle large dV/dt so as you go up in frequency, this will be the limit at some point. tan fi heating comes to mind too. How much voltage swing at high frequency do you need? \$\endgroup\$ – winny Dec 28 '16 at 18:22
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    \$\begingroup\$ Start capacitors and run capacitors are quite different beasts. I'd expect run capacitors to be fine across the audio range, and their inductance to become important as you approach RF frequencies. Best way to be sure would be testing. Start capacitors, with much higher capacitance ... I'd be doubtful about them. \$\endgroup\$ – Brian Drummond Dec 28 '16 at 19:06
  • \$\begingroup\$ @winny I'm expecting voltage swing of 100volts peak to peak but I may be able to accomplish the task with as little as 40volts \$\endgroup\$ – JamesHoux Dec 28 '16 at 19:28
  • \$\begingroup\$ @winny what is tan fi heating? \$\endgroup\$ – JamesHoux Dec 28 '16 at 19:30
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    \$\begingroup\$ @Jim tan fi heating is when the high frequency causes heating within the dielectric of the capacitor (ever wondered how nonmetallic objects are heated by microwaves... same process) \$\endgroup\$ – Sam Dec 28 '16 at 20:15

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