Electrical Machines In speed control of DC Series motor, speed lower than the rated speed can be obtained by Connecting an additional resistance in the armature circuit. Connecting an additional resistance in stator circuit. Connecting an additional resistance in the field circuit. Any of the above. Connecting an additional resistance in the armature circuit. Connecting an additional resistance in stator circuit. Connecting an additional resistance in the field circuit. Any of the above. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If residual magnetism of a shunt generator is destroyed accidentally it may be restored by connecting its shunt field in reverse. to earth. to an AC source. to a DC source. in reverse. to earth. to an AC source. to a DC source. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When R2 is rotor resistance, X2 the rotor reactance at supply frequency and s the slip, then the condition for maximum torque under running condition will be R2 = s2X2. R2 = s2X2. sR2 = X2. R2 = sX2. R2 = s2X2. R2 = s2X2. sR2 = X2. R2 = sX2. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Which of the following is/are the advantages of carbon brush over the copper brush? In case of any sparking they will be less damaged than copper brushes They are not hard as copper brush All of these They are self lubricating in nature In case of any sparking they will be less damaged than copper brushes They are not hard as copper brush All of these They are self lubricating in nature ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The field system of an alternator is usually excited 230 V AC. 110 / 220 V AC. 3 - Φ, 50 Hz and 400 V. 250 / 250 V DC. 230 V AC. 110 / 220 V AC. 3 - Φ, 50 Hz and 400 V. 250 / 250 V DC. 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, 4 ,5 1, 3, 5 1, 4 2, 3 , 5 2, 4 ,5 1, 3, 5 1, 4 2, 3 , 5 ANSWER DOWNLOAD EXAMIANS APP
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