Hello,
I have an RF generator that outputs power at 6.78Mhz with an output impedance of 50 ohms. I want to use this for induction heating and have seen it work great for my application.
I have wound my coil around the piece I want to heat and measured :
inductance (1.9940micro Henries)
impedance (85.145 ohms)
and resistance (5 ohms) at the 6.78Mhz using a Keyence E4990A impedance analyzer.
I then select and measure my capacitors
280 pF,
84.6 ohms impedance and
2.34 ohm resistance.
My issue is, I then put the capacitors and inductor in the analyzer connected in parallel and I see a high resistance of 431.68 ohms? where is this coming from?
My impedance is 431.68 ohms, the resistance is 431.68 ohms and my phase angle is 0.045 degree implying I have successfully found resonance at 6.78Mhz but for some reason my purely resistive circuit is unexpectedly high and i need it to be at the 50 impedance to match my power supply . This is even before I put it into my circuit that connects to the power supply.
I have two circuits from the vendor that are 50ohms impedance and 0 phase angle and have variations in coil size & turns and they heat the part very fast. When I go to make my own this high resistance still allows the part to heat but it is noticeably slower despite being very similar to the two physically different circuits i received.
I am a mechanical engineer learning all this on the fly, any help would be appreciated. Attached are the data sheets of the caps i used which should be rated for this.
I have an RF generator that outputs power at 6.78Mhz with an output impedance of 50 ohms. I want to use this for induction heating and have seen it work great for my application.
I have wound my coil around the piece I want to heat and measured :
inductance (1.9940micro Henries)
impedance (85.145 ohms)
and resistance (5 ohms) at the 6.78Mhz using a Keyence E4990A impedance analyzer.
I then select and measure my capacitors
280 pF,
84.6 ohms impedance and
2.34 ohm resistance.
My issue is, I then put the capacitors and inductor in the analyzer connected in parallel and I see a high resistance of 431.68 ohms? where is this coming from?
My impedance is 431.68 ohms, the resistance is 431.68 ohms and my phase angle is 0.045 degree implying I have successfully found resonance at 6.78Mhz but for some reason my purely resistive circuit is unexpectedly high and i need it to be at the 50 impedance to match my power supply . This is even before I put it into my circuit that connects to the power supply.
I have two circuits from the vendor that are 50ohms impedance and 0 phase angle and have variations in coil size & turns and they heat the part very fast. When I go to make my own this high resistance still allows the part to heat but it is noticeably slower despite being very similar to the two physically different circuits i received.
I am a mechanical engineer learning all this on the fly, any help would be appreciated. Attached are the data sheets of the caps i used which should be rated for this.
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