inductory-to-delta
Does a Y to delta transform for resistors work the same way when inductors a connected in a similar fashion?
simulate this circuit – Schematic created using CircuitLab
I have a load bank that is wired in a Y configuration. I'm given the specks for loading in a delta configuration. I'm trying to figure out if these loads will work.
It's unclear from your circuit if any of the inductors are also carrying a dc current - this can make a significant difference to your choice of inductor size due to saturation properties and the inductance value "retuning" with variable current levels.
Regards the AC side of things, you have hit a couple of important points namely Q and Self-Resonant-Frequency (SRF).
Q is simply a calculation of the inductive reactance at a particular frequency divided by its series equivalent resistive losses. For resistive losses you cannot assume these are measurable at DC - they embrace: -
The bigger Q is at a particular frequency the higher the resonant peak will be in a tuned circuit (not always an advantage of course).
Self resonant frequency is due to the parasitic capacitance of the windings turning an inductive reactance (below SRF) to a capacitve reactance above SRF - if you are using inductors as tuning components then make sure SRF is a lot higher than your maximum operating frequency.
Skin and proximity effects: -
How are you measuring the current ? A sense resistor, or a current clamp ?
Small amounts of capacitive coupling to your current sense R, or poor common-mode rejection in your scope will cause this type of waveform.
Also, if the inductor is relatively large (physically), it is possible there is some capacitance between the ends of the windings -- you don't have a pure inductance -- and so the total current can have discontinuities.
(I see your schematic now).
Check how your scopes' probe is grounded -- it should be just at the R also. In addition, sometimes scopes can pickup common-mode signals -- try to connect both the probe and the ground clip together to the bottom of the R -- you should see no signal, but anything you do see is in indication of this.
What diode are you using -- if it is not a fast one, reverse recovery current will actually cause large transient currents and noise spikes in the circuit.
Best Answer
Y to Δ conversion formula remains the same for all impedances (\$Z\$). In case the impedance is just a resistor, replace \$Z\$ with \$R\$. In the case of an inductor, replace with \$Z=j L \omega\$. In the case of a capacitor, it must be \$Z=1/(j C \omega)\$. In case of combinations of these elements, add them and replace \$Z\$.