Overheating of relay contacts or contact born out is due to

slow making and breaking of load circuit contacts
foreign matter on the contact surface
too low contact pressure
all of the above

The correct answer is: D. all of the above.

Overheating of relay contacts or contact born out is due to slow making and breaking of load circuit contacts, foreign matter on the contact surface, and too low contact pressure.

  • Slow making and breaking of load circuit contacts can cause overheating because the contacts are not making or breaking contact quickly enough. This can cause arcing, which generates heat.
  • Foreign matter on the contact surface can also cause overheating because the foreign matter can insulate the contacts and prevent them from making good contact. This can also cause arcing.
  • Too low contact pressure can also cause overheating because the contacts are not making good contact. This can also cause arcing.

All of these factors can contribute to overheating of relay contacts or contact born out. It is important to keep these factors in mind when troubleshooting relay problems.