Ans: Moving primary fixed secondary, double side LIM
Advantages: i) No Need of backing of iron along the track as laminated core is used in each primary. ii) Uniform air gap maintained. iii) Higher thrust/force. iv) Better magnetic circuit performance. v) Better power factor.
Disadvantages: i) Problem of maintaining uniform clearance between secondary Al plate and two primaries all along the track, particularly at points and crossing. ii) Costly due to Al plate all along the track. iii) Overall dimensions and weight higher iv) Increases the risk of accidents result from change in gap due to sudden production of lateral forces on the moving vehicle.