Description : A suspension insulator string has three units with ground capacitance of 0.2 C and self capacitance of C. Its string efficiency is (a) 75% (b) 78% (c) 80% (d) 85%

Description : A suspension type insulator has three units with self-capacitance C and ground capacitance of 0.2 C having a string efficiency of (a) 80% (b) 82% (c)78% (d) 76%

**Answer :** A suspension type insulator has three units with self-capacitance C and ground capacitance of 0.2 C having a string efficiency of 78%

Description : A suspension type insulator has 2 units with self capacitance C and ground capacitance of 0.2 C. Each unit can withstand for a maximum voltage of 11 kV. Its string efficiency is (A) 78% (B) 82% (C) 80% (D) 84%

**Answer :** Inductance and capacitance in the electrostatic system of units has the dimensions of length.

Description : Three capacitors 15µf, 18µf and 12µf are connected in a circuit. Find equivalent capacitance when they are connected in – 1) Series 2) Parallel

**Answer :** Ans: Value of equivalent capacitance: Given: C1= 15μF, C2=18 µF, C3= 12µF i)For Series combination of capacitors: 1/Cs = (1/C1)+( 1/C2) +(1/C3) = (1/15)+( 1/18)+( 1/12) 1/Cs = 0.0666+0.0555+0. ... Cs = 4.868 µF ii) For parallel combination of capacitors: Cp = C1 + C2 + C3 = 15 +18+ 12 = 45 µF