The resistance R3 & R4 are connected in series = (30 + 70) = 100Ω Now three resistor i.e 100Ω, 100Ω & 50Ω is connected in parallel 1/Rp = 1/100 + 1/100 + 1/50 Rp = 100/4 = 25 Ω Resistance 50Ω and 25Ω are connected in series. Rtotal = (50 + 25)Ω Rtotal = 75Ω
Flux in coil A = 0.05 mWb = 5 × 10−5 wb = φA No. of turns NA = NB = 1000 Flux linkage in a coil with B = Flux linkage in coil A × 80/100 = 0.8 × 5 × 10−5 = 4 × 10−5 wb =0.04 mwb
Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.
Sudden changes of load on synchronous motors may sometimes set up oscillations that are superimposed upon the normal rotation, resulting in periodic variations of a very low frequency in speed. This effect is known as hunting or phase-swinging.