SSC JE Electrical 2019 with solution SET-2
The combined inductance of two coils connected in a series is 0.6H and 0.1H, depending on the relative directions of the currents to the coils. If one of the coils when isolated has a self-inductance of 0.2 H, then calculate the natural inductance?
The combined inductance of two coils connected in series L = L1 + L2 + 2M In series adding case L1 + L2 + 2M = 0.6 H ——–(1) In series opposing case L1 + L2 − 2M = 0.1 H ——–(2) Subtracting eqn (2) from eqn (1) we get 4M = 0.5 H M = 0.125 H Let L1 = 0.2 H (since the coil when isolated, its self-inductance is 0.2 H) Putting the value of M & L1 in equation (2) 0.2 + L2 + 2 ×0.125 = 0.06 0.2 + L2 = 0.35 L2 = 0.15 H
The wattage rating for a ceiling fan motor is in the range of 50 to 150 W. if the ceiling Fans size ranges from 36 inches to 56 inches then the total wattage use is 55 to 100 watts.. A 48-inch ceiling fan will use 75 watts.
In the exclusive OR gate (XOR gate) has two inputs The ouput will be 1 when either input is 1 i.e X = 1 and Y = 1, but not when both the inputs are 1. If both the input is zero i.e X = 0 and Y = 0, then the output is 0.
The melting point of Eureka is 1221 to 1300 °C The melting point of Kanthal is 1,425 °C The melting point of Nichrome is 1400 °C The melting point of Graphite is 3,600°C Hence Eureka has the least range of temperature.
We use universal motors in mixer grinders. Universal motors can run both on a.c. and d.c. The universal motor works on the same principle that DC series motor works. DC series motor has the characteristics of operating at high-speed when there is no load and operating at low-speed when the load is applied. It has high starting torque characteristics. So it is used in mixers, where initially we put some load at starting.
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