Electrical Machines Oil is provided in an oil filled transformer for insulating. both cooling and insulation. lubrication. cooling. insulating. both cooling and insulation. lubrication. cooling. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed the field winding must be replaced the armature connection must be reversed field winding must be excited by low voltage dc supply the field winding connection must be reversed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature reaction mmf in a DC machines has a form of trapezoidal. sinusoidal. rectangular. triangular. trapezoidal. sinusoidal. rectangular. triangular. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the handle of a three point starter goes to back to OFF position, it may be due to zero or very low voltage supply. all of these. over load. high filed circuit resistance. zero or very low voltage supply. all of these. over load. high filed circuit resistance. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Direction of rotation of DC motor is reversed by Adding resistance to field circuit. Reversing supply connection. Interchanging armature and field connection. Reversing armature connection or field connection. Adding resistance to field circuit. Reversing supply connection. Interchanging armature and field connection. Reversing armature connection or field connection. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 2, 3 , 5 1, 3, 5 2, 4 ,5 1, 4 ANSWER DOWNLOAD EXAMIANS APP
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