Search results
Results from the WOW.Com Content Network
Form C contacts ("change over" or "transfer" contacts) are composed of a normally closed contact pair and a normally open contact pair that are operated by the same device; there is a common electrical connection between a contact of each pair that results in only three connection terminals.
Time-delay relay contacts must be specified not only as either normally open or normally closed, but whether the delay operates in the direction of closing or in the direction of opening. The following is a description of the four basic types of time-delay relay contacts. First, we have the normally open, timed-closed (NOTC) contact.
SPST normally-open Form-X (double make) hermetically sealed DC contactor cut-away animation showing main movable contacts and AUX feedback plunger Powerful DC contactor with electro-pneumatic drive. A contactor has three components: The contacts are the current-carrying part of the contactor. This includes power contacts, auxiliary contacts ...
This can also occur during the open-to-close (MAKE) transition due to contact bounce. The electric arc occurs between the contact points (electrodes) both during the transition from closed to open (BREAK) and from open to closed (make) when the contact gap is small and the voltage is high enough. Heating due to arcing and high current density ...
The contacts are usually normally open, closing when a magnetic field is present, or they may be normally closed and open when a magnetic field is applied. The switch may be actuated by an electromagnetic coil , making a reed relay , [ 2 ] or by bringing a permanent magnet near it.
In a switch where the contacts remain in one state unless actuated, such as a push-button switch, the contacts can either be normally open (abbreviated "n.o." or "no") until closed by operation of the switch, or normally closed ("n.c." or "nc") [nb 1] and opened by the switch action.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Normally closed mercury relay, with coil around top of tube and adjustable angle. A mercury relay (mercury displacement relay, mercury contactor) is a relay that uses mercury as the switching element. They are used as high-current switches or contactors, where contact erosion from constant cycling would be a problem for conventional relay contacts.