DieselShip's Online Content Library

Q4.a) Explain the construction and principle of operation of permanent magnet moving coil instrument. (8)

b) A permanent magnet moving coil instrument has a coil of dimension 15 mm × 12mm. The flux density in the air gap is 1.8 × 10-3 wb/m2 and the spring constant is 0.4 × 10-6 Nm / rad. Determine the number of turns required to produce an angular deflection of 900 when a current of 5 mA is flowing through the coil. (8)