A. What is back emf? Derive the relation for the back emf and the supplied voltage in terms of armature resistance. b) An 8kw, 230V, 1200 rpm d.c shunt motor has Ra = 0.7Ω. The field current is adjusted until, on no- load with a supply of 250V, the motor runs at 1250 rpm and draws armature current of 1.6 amps. A load torque is then applied to the motor shaft which causes la to raise to 40 A and the speed falls to 1150 rpm. Determine the reduction in the flux per pole due to the armature reaction.

Comments

Post a Comment

Popular posts from this blog

EM MEO Class 1 Written Question (JAN 2023)

EXAMINATION OF MARINE ENGINEER OFFICER ENGINEERING MANAGEMENT M.E.O CLASS – I TIME - 3 HOURS  Total Marks – 100 Q1. Improvements in Rudder efficiency can considerably contribute to improving propulsion   effectiveness. Discuss common rudder-efficiency improvements devices/ techniques currently in use,   referring to the following: (a) Rudder Thrust Fins (b) Asymmetric Rudders (c) Rudder Bulbs (d) Grim Vane Wheels Q2 . a) Briefly discuss Anti fouling convention and state all Documents and records to be maintained on a ship to demonstrate Anti fouling convention compliance. c) Discuss various alternatives to tin-based antifouling paints, with specific reference to the following   types: - (i) Controlled Depletion Polymer (CDP) paint; (ii) Self-Polishing Copolymer (SPC) paint; (Ill) Hybrid TBT free paint ; (iv) Fouling Release paint. Q3 . State the different types of marine insurance policies that could be taken by owners, shippers or   other related parties....
Read more