Example 25.6. A coil of an electromagnetic relay is associated with a magnetic circuit whose reluctance is given by = a + bx where a and b are positive constants decided by the details of the magnetic circuit, in which x is the length of the air-gap between fixed and movable members. If the coil is connected to an A.C. source where voltage is described by v = V sin cox, www find the expression for the average force on armature, with air-gap held constant at x Solutio ablished in Wah

GENERAL RLC CIRCUITS: Solve and show your solution completely. Make sure your answers are in 4 decimals places. The ohmic resistance of a large magnetic contactor is measured to be 20 ohms. A 230 V 60 Hzis impressed upon the contactor and the current is taken as 3.2 amperes. Neglecting core loss,determine the inductance of the contactor in mH.

A ring of ferromagnetic material has a rectangular section. The inner diameter is 15 cm.The outer diameter is 24 cm. And the thickness is 5 cm. There is a coil of 500 turns wound onthe ring. When the coil has a current of 10 A, the flux in the core is 0.0007 Wb. Theaverage length of the ring is Ln=0.66m Determine:a) The magnetomotive force.b) The intensity of the magnetic field and the flux density.c) Reluctance, permeability and relative permeability.

A three-legged ferromagnetic magnetic core with the coil dimensions shown below has a of 500 turns wrapped around the right leg. The core relative permeability is 4000 times, The magnetic flux in the left leg of the core has a value of 40 mWb. The center leg has an air gap of 0.8 mm, its fringing effect is neglected. Draw the corresponding magnetic circuit and find the values of the coil current i, and the flux in each leg of the core. cm 10 cm, 25cm 25 cm 10 cm 10 cm 25 cm 0.8 mm 500 turns 10 cm Core depth = 10 cm