Electrical Question and Answers:

*What is different between grounding and earthings?

Grounding means connecting the neutral point of the load to the ground to carry the residual current in case of unbalanced conditions through the neutral to the ground whereas earthing is done in an electric equipment in order to protect he equipment in occurence of fault in the system. 

*How many types of colling system it transformers?

1. ONAN (oil natural,air natural)

2. ONAF (oil natural,air forced)

3. OFAF (oil forced,air forced)

4. ODWF (oil direct,water forced)

5. OFAN (oil forced,air forced). 

*Define IDMT relay?

It is an inverse definite minimum time relay.In IDMT relay its operating is inversely proportional and also a characteristic of minimum time after which this relay operates.It is inverse in the sense ,the tripping time will decrease as the magnitude of fault current increase.

*what is the principle of motor?

Whenever a current carrying conductor is placed in an magnetic field it produce turning or twisting movement is called as torque.

*What is SF6 Circuit Breaker?

SF6 is Sulpher hexa Flouride gas.. If this gas is used as arc quenching medium in a Circuitbreaker means SF6 CB. 

*what is ACSR cable and where we use it?

ACSR means Aluminium conductor steel reinforced, this conductor is used in transmission & distribution. 

*What will happen if DC supply is given on the primary of a transformer?
   Mainly transformer has high inductance and low resistance.In case of DC supply there is no inductance ,only resistance will act in the electrical circuit. So high  electrical current will flow through primary side of the transformer.So for this reason coil and insulation will burn out.