(1, 2) RMS, Cap./Ind. Reactance, Lead/Lag

How do rotating electrical machines produce a sinusoidal waveform? What is standard AC supply frequency in aus?

Naturally, via providing relative motion between coil + magnetic field in an alternator to produce a certain frequency. Standard AC supply frequency is 50Hz

How to find instantaneous voltage/current in a phasor diagram?

(V = V_maxsinΘ)
V = instantaneous voltage V, V_max = peak voltage V, Θ = rotational angle. Change V to I for current

How many cycles of a sin waveform will a two-pole alternator produce? How about a four-pole?

One sin waveform for each pole pair, so one for a two-pole and two for a four-pole

How is frequency, time, or amount of poles in an alternator calculated?

(f=nP/120, T=1/f)
f = frequency Hz, n = alternator RPM, P = poles number, T = time seconds

How is instantaneous value of induced emf found using angle conductor has moved?

(e=BlvsinΘ)
e = instantaneous value of induced emf V, B = flux tensity T, effective conductor length m, Θ = angular displacement from reference point

What is RMS value of a sine wave and what is its relationship with max value?

Root-mean-squared value = effective value = equivalent DC value. (Vrms=Vmax*.707) or (Vmax=Vrms*1.414), Vrms = rms value of voltage V, Vmax = max value of voltage V, V can be I for current

How is average AC voltage or current over half a cycle calculated?

(V_AV=V_M*.637), V_AV = sine wave’s average voltage. V_M = maximum votlage, V can be I for current

How is phase difference angle calculated and what is it used for?

Angle = d/T *360, where d = time displacement between waveforms and T = period of waveforms.

How to find values in resistive load connected to AC supply?

(V_RMS=I*R_RMS), basically Ohm’s law

What is a power curve?

Power curve is a representation of current + voltage flow, on the positive side of a phasor diagram only. Proportional to combined current and voltage curve.

How to find inductive reactance? What is inductance?

(X_L=2πfL) where X_L = inductive reactance Ω, f = frequency Hz, L = inductance H (henrys)
Inductance is ability of conductor/component to induce voltages that oppose change in current by storing energy as magnetic field

How to find capacitive reactance? What is capacitance?

(Xc=1/(2πfC)) where Xc = capacitive reactance Ω, f = frequency HZ, C = capacitance F (farads)
Capacitance is ability of circuit/component to store electrical energy as electrical charge, which can be released to help balance power factor’s inductive load

What decreases power factor in a circuit and what can increase it again?

Power factor is closest to 1 in a purely resistive circuit, but inductive reactance loads which momentarily store energy will produce a phase difference between voltage and current waveshapes, lowering the power factor. The factor can be raised with capacitive reactance loads which neutralise the inductive.