Electrical Machines which of the following type of brush and their application is/are correct electro graphite → large ratings carbon brush → normal ratings copper graphite → low voltage high current density All of these electro graphite → large ratings carbon brush → normal ratings copper graphite → low voltage high current density All of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines φA DC shunt machine generates 250 V on open circuit at 1000 RPM. Armature resistance is 0.5 Ω, field resistance 250 Ω. When running as a motor takes 4 A at 250 V. Calculate the speed when running as a motor taking 40 A at 250 V. Armature reaction weakens the field by 4%. 970 RPM 940 RPM 920 RPM 960 RPM 970 RPM 940 RPM 920 RPM 960 RPM ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in DC generators will result in open circuit. reduction in generated emf. short circuit. increase in slip. open circuit. reduction in generated emf. short circuit. increase in slip. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements about commutating poles which are fitted on most large dc Shunt motors: 1. The commutating poles are placed in the geometric neutral plane and their number is usually Equal to the number of main poles 2. The winding on the commutating poles is connected in series with the shunt-field winding on the main poles 3. The polarity of the commutating pole must be that of the next pole further ahead 4. The commutating poles neutralize the reactance voltage produced in the coil undergoing Commutation. Of these statements, 1, 2 and 4 are correct 1 and 4 are correct 1, 2 and 3 are correct 2, 3 and 4 are correct 1, 2 and 4 are correct 1 and 4 are correct 1, 2 and 3 are correct 2, 3 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Torque developed in the rotor is directly proportional to slip inversely proportional to slip not dependent on the slip either of these directly proportional to slip inversely proportional to slip not dependent on the slip either of these ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a seperately excited DC Motor if field current is increased, it will Reduce armature heating. Increase acceleration duration. Increase speed Reduce starting torque. Reduce armature heating. Increase acceleration duration. Increase speed Reduce starting torque. ANSWER DOWNLOAD EXAMIANS APP
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