Electrician Theory ||DC Machine Important Points - 02||

1. Copper is used to make split rings.

2. A compound generator is called a level compound generator if the output voltage of the generator remains constant under any load condition.

3. The main field function in the DC generator is opposed by the wind current generated by the armature current.

4. DC. Motor back EMF The field depends on the flux.

5. The dc series motor produces 10 Newton meter torque at a normal current of 2 amperes. If the load current is reduced to 4 amperes, then a torque of 40 newton meters will be generated.

6. The electric carrying force generated by increasing the field current cannot be increased beyond a certain limit. 

7. The voltage drop of the brushes increases with increasing load current.

8. If slip rigs are added to the armature conductor of the generator, then alternating current (AC) will be found in the output.

9. The positions of the brushes in the DC generator are changed to neutralize the cross magnetizing effect.

10. When the supply terminals of the DC shunt motor are interchanged, the motor will rotate in the same direction as before.

11. If the DC compound generator is not used for a long time, it can lose its residual magnetism. To regain residual magnetization the shunt field must be replaced by a d.c. Should be added from source.

12. The air gap between the pole face and armature must be kept to a minimum to obtain a powerful magnetic field in the electric motor.

13. The potential generated in armature coils is transported to the output terminals with the help of commutators and bruises.

14. The polarity of the generated voltage depends on the polarity of the wiring supply and the direction of rotation of the armature.

15. The supplies supplied to the coils of the motor are supplied from the bores at the input terminals.

16. It is necessary to install Compensating Winding in a DC generator whose load is variable.

17. The field circuit resistance should be reduced to improve the decrease in terminal voltage with increasing load in the DC generator.

18. The starting resistance is added to the range order of the armature.

19. If the wind of the DC series motor comes to zero, then its speed will reach infinity.

20. The split rings at the ends of the coil help the output current to flow in one direction.

21. The resistance of the shunt field circuit must be less than the field critical value to create a voltage.

22. The shunt field should always be added parallel to the armature.

23. Over compound generators are suitable for providing stable voltage to the load with long transmission lines.

24. The purpose of placing the starter in the DC motor is to limit the starting current.

25. The external characteristic of a DC shunt generator indicates the correlation between the terminal voltage and the load current.

26. DC Series motors are used for loads with higher starting torque and lower starting speed.

27. The voltage produced in only one turn coil is very low. The potential is also increased many times by increasing these terns several times.

28. If the resistance of 500 Ohms is connected to a 50 volt supply, the current flowing will be 100 milli amperes.

29. If the self excited DC shunt generator is not able to create voltage, one reason can also be that there is not a correct relationship between its direction of rotation and the direction of field current.

30. The DC shunt generator is delivering 30 amperes at 230 volts. The shunt field winding and armature resistance are 115 and 0.5 ohms respectively when the armature voltage drop will be 16 volts.