Elementary electric machine

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EXERCISES FOR ELECTRIC POWER SYSTEMS COURSE ENERGY DEPARTMENT, Electrical section Class 2 Elementary electric machine An electric circuit configured as in Figure 2.1 is considered. The circuit characteristics are: B 1.2 T d 80 cm V 100 V R 0.5 Ω Figure 2.1. Elementary electric machine The magnetic field B is perpendicular to the figure’s plane and is entering the figure’s plane. Assuming that the mobile iron bar can move along the fixed iron part with a constant frictional force of 5 N, determine: 1. the startup electrodynamic force ( /g1832 /g3032/g3031 /g2868); 2. the no-load velocity of the mobile iron bar when the frictional force is neglected and when it is considered; 3. in no-load conditions and considering the frictional force, the efficiency of the machine, the electrodynamic force acting on the mobile part, the emf induced by the magnetic field in the electric circuit and the absorbed current ( I); 4. the mechanical characteristic of the machine; 5. the velocity of the mobile iron bar when a mechanical load of 100 N is applied and the frictional force is considered; 6. for the operating conditions described by question 5 the efficiency of the machine, the electrodynamic force acting on the mobile part, the emf induced by the magnetic field in the electric circuit and the absorbed current ( I); 7. the elementary electric machine operates in the conditions described by question 5. At one moment of time breaker S is closed and, in the same time, the mechanical load applied to the mobile part becomes null. Describe the new operating conditions. V I S d x BI R