16-08-2014, 08:38 PM
Yes, the resultant circuit is resonant. Would that cause any problems, you ask. Answer: no.
It's back to basic a.c. theory to establish the validity of those remarks.
A parallel resonant circuit presents a high impedance, so the current flowing in that resultant circuit will be a minimum. For the inductive part of the load, the current in it will lag the applied voltage, but the current in the added capacitor will lead the applied voltage. By choosing the right value (µF) of capacitor, the reactance of the capacitor (Xc) just equals the reactance of the inductive part of the load (XL). Since inductive reactance and capacitive reactance are 180° apart and the magnitude of the reactances are now equal, the net reactance must be zero. In other words, resonance.
Therefore, to calculate the capacitance of the added capacitor, its just a simple matter of using the standard formula for a L/C tuned ct. Obviously, the inductance of the load needs to be known and there is the embedded assumption that that inductance will not change over the a.c. cycle or as the load on the motor (say) varies. If either do change, then a mid-value of inductance should be chosen.
Al.
It's back to basic a.c. theory to establish the validity of those remarks.
A parallel resonant circuit presents a high impedance, so the current flowing in that resultant circuit will be a minimum. For the inductive part of the load, the current in it will lag the applied voltage, but the current in the added capacitor will lead the applied voltage. By choosing the right value (µF) of capacitor, the reactance of the capacitor (Xc) just equals the reactance of the inductive part of the load (XL). Since inductive reactance and capacitive reactance are 180° apart and the magnitude of the reactances are now equal, the net reactance must be zero. In other words, resonance.
Therefore, to calculate the capacitance of the added capacitor, its just a simple matter of using the standard formula for a L/C tuned ct. Obviously, the inductance of the load needs to be known and there is the embedded assumption that that inductance will not change over the a.c. cycle or as the load on the motor (say) varies. If either do change, then a mid-value of inductance should be chosen.
Al.
