1. The problem statement, all variables and given/known data A coil of 450 turns is wound uniformly round a cast steel ring. The ring has a crosssectional area of 750mm2 and a mean circumference of 600mm. A flux of 0.825mWb is produced in the ring. (Given that H = 800At/m at that flux). a. Calculate the reluctance of the ring b. Calculate the current required to produce the given flux. 2. Relevant equations Φ=BA μ=B/H S=l/μoμrA Φ=F/S 3. The attempt at a solution a. Φ=BA B=Φ/A Flux density in ring: 0.825x10-3/750x10-6 = 1.1T μ=B/H =1.1/800 =1.375x10-3 S=l/μoμrA =600x10-3/1.375x10-3x4πx10-7x750x10-6 =4.63x1011A/Wb b. Φ=F/S =0.825x10-3=mmf/4.63x1011 mmf=0.825x10-3x4.63x1011 =381975000A These answers look very wrong to me but I am unsure where I have gone wrong?