Electrical Machines The armature MMF waveform of a DC machine is triangular. sinusoidal. rectangular. pulsating. triangular. sinusoidal. rectangular. pulsating. 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 3 are correct 1, 2 and 4 are correct 1 and 4 are correct 2, 3 and 4 are correct 1, 2 and 3 are correct 1, 2 and 4 are correct 1 and 4 are correct 2, 3 and 4 are correct ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a 3 - Φ induction motor none of them. power factor at starting is high as compared to that while running. power factor at starting is low as compared to that while running. power factor at starting in the same as that while running. none of them. power factor at starting is high as compared to that while running. power factor at starting is low as compared to that while running. power factor at starting in the same as that while running. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the armature electric current is increased to double its previous value, and the time of commutation is halved, how will the reactance voltage vary? It will be doubled. It will becomes four times. It will be halved. It will remain the same. It will be doubled. It will becomes four times. It will be halved. It will remain the same. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The direction of rotation of a 3 - Φ induction motor can be reversed by transposing any two leads from supply. transposing all the three leads from the supply. transposing any two leads from slip rings. disconnecting any one phase. transposing any two leads from supply. transposing all the three leads from the supply. transposing any two leads from slip rings. disconnecting any one phase. 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 all of these. over load. high filed circuit resistance. zero or very low voltage supply. all of these. over load. high filed circuit resistance. zero or very low voltage supply. ANSWER DOWNLOAD EXAMIANS APP
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