Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 1, 2, 3 2, 3, 4, 5 2, 3 ,5 2, 3, 4 1, 2, 3 2, 3, 4, 5 2, 3 ,5 2, 3, 4 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The emf induced in the dc generator armature winding is AC DC None of these AC and DC AC DC None of these AC and DC ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Minimum allowable resistivity of power transformer insulating oil is generally taken as 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 3 X 1012 Ω - cm at 27°C and 0.3 X 1012 2 X 1012 Ω - cm at 27°C and 0.2 X 1012 1 X 1012 Ω - cm at 27°C and 0.1 X 1012 4 X 1012 Ω - cm at 27°C and 0.4 X 1012 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following motor is suitable for frequent starting and stoppings? All of these Capacitor start capacitor run motor Resistance split phase motor Capacitor start motor All of these Capacitor start capacitor run motor Resistance split phase motor Capacitor start motor ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines No load saturation characteristics are plotted between short circuit current and armature current no load voltage and armature current short circuit current and field current no load voltage and field current short circuit current and armature current no load voltage and armature current short circuit current and field current no load voltage and field current ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines which of the following type of brush and their application is/are correct copper graphite → low voltage high current density electro graphite → large ratings carbon brush → normal ratings All of these copper graphite → low voltage high current density electro graphite → large ratings carbon brush → normal ratings All of these ANSWER DOWNLOAD EXAMIANS APP
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