what is the function of NAT & NAC contacts in breaker
control switch (TNC)??

Answer Posted / rajesh t k

The NAT and NAC contacts are provided on TNC switch to facilitate additional functionalities from the TNC switch than mere Tripping or Closing.


These contacts are also known as Lost Motion Contacts. They help identify the last operation (Trip/Close) performed by the operator through the TNC switch.

The NAC contact will be closed whenever the operator turns the TNC lever to Close position and the contacts stays closed even after the lever is returned to the Neutral position by the operator, until the lever is turned to Trip side.

Hence, the 'Auto Trip' indication can be given via the NAC contact(instead of giving through an NO contact of the master trip relay), in series with the CB's 52b contact. That is, this is just an alternate way to wire up the 'Auto Trip' indication.

The NAT contact, likewise will be through whenever the CB has tripped via the TNC lever switch by the operator, until the lever is turned to Close position again.

Is This Answer Correct ?    12 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

what is the transformer rush current?

1563


I want to design a heating coil of 80/20 nicrome for 3.5KW please give me the calculations choosing for physical dimensions assume coil voltage will be 110V AC assume necessary conditions

1191


What is Primary And Secondary Injection Test of Relay and Other Electrical Devices. How IT is carried out.

3004


what is PWM in IGBT and how it works for drive.?

1217


difine electrical ballast in HPSVL

1553






Write down the brushes of a de machine.

1416


What is a fuse? How does it work? What are materials used?

1515


i want design of D.C.MOTOR 1HP 960RPM AND 2HP 960RPM ITS URRGENT

1541


What is the principle of HIGH SPEED DIRECT DRIVE MOTOR ?

1504


model question paper for supervisor trainee

1590


high voltage transformer input voltage,current and amps rating..distributed transformer input voltage,current and amps rating...

1528


how to prepare the technical test

1602


what is the minimum voltage require to injure our body?

5632


What happened when capacitor connect series in ac circuit?

954


Is neutral transformer can be called as control transformer?

1508