11. In an ac servometer, the control winding is supplied with input voltage of
    

1. 1. same frequency as the reference winding voltage but with 90° phase difference.

   
   
   

   2. same frequency as the reference windings voltage and also having same phase.

   
   
   

   3. any frequency compared to t he reference winding but with 90° phase difference.

   
   
   

   4. any frequency compared to the reference winding but of the same phase.

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

12. If 1.8° step, 4-phase stepper motor has a total of 40 teeth on 8 poles of startor, then number of rotor teeth for this motor will be
    

1. 1. 40

   
   
   

   2. 50

   
   
   

   3. 100

   
   
   

   4. 80

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

---

---

13. A single-phase transformer when supplied from 220V, 50 Hz has eddy current loss of 50 W. If the transformer is connected to a voltage of 330 V, 50 Hz, the eddy current loss will be_______ W.

1. 1. 112.5 W

   
   
   

   2. 12 W

   
   
   

   3. 515 W

   
   
   

   4. None of the above

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

---

14. A 200/100 V, 50 Hz transformer is to be excited at 40 Hz from the 100 V side. For the exciting current to remain the same, the applied voltage should be _______ V.

1. 1. 10 V

   
   
   

   2. 30 V

   
   
   

   3. 40 V

   
   
   

   4. 80 V

   
   
   

---

1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

---

---

15. A single-phase transformer when supplied from 220V, 50 Hz has eddy current loss of 50 W. If transformer is connected to a voltage of 330 V, 50 Hz, then eddy current loss will be _______ W .

1. 1. 11.25 W

   
   
   

   2. 112.5 W

   
   
   

   3. 21.05 W

   
   
   

   4. 1125 W

   
   
   

---

1. View Hint View Answer Discuss in Forum

   P_e = k_e f² B_m² , and V = 4.44 f B_m AN
   

   ∴	Pe1	=		f1 Bm1		2	=		V1		2
   	Pe2			f2 Bm2					V2

   
   

   ⇒ Pe2 = Pe1.		V1		2	= 50.		330		2	= 112.5 watts
   		V2					220

   Correct Option: B

   P_e = k_e f² B_m² , and V = 4.44 f B_m AN
   

   ∴	Pe1	=		f1 Bm1		2	=		V1		2
   	Pe2			f2 Bm2					V2

   
   

   ⇒ Pe2 = Pe1.		V1		2	= 50.		330		2	= 112.5 watts
   		V2					220

---