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A closed transition transfer switch (CTTS) is also called a make-before-break transfer switch. A typical emergency system uses open transition, so there is an inherent momentary interruption of power to the load when it is transferred from one available source to another (keeping in mind that the transfer may be occurring for reasons other than ...
Where a switch contains both normally open (NO) and normally closed (NC) contacts, the order in which they make and break may be significant. In most cases, the rule is break-before-make or B-B-M ; that is, the NO and NC contacts are never simultaneously closed during the transition between states.
Each key of a computer keyboard, for example, is a normally-open "push-to-make" switch. A "push-to-break" (or normally-closed or NC) switch, on the other hand, breaks contact when the button is pressed and makes contact when it is released. An example of a push-to-break switch is a button used to release a door held closed by an electromagnet.
Contact sequence — "make before break" or "break before make". For example, the old style telephone exchanges required make-before-break so that the connection did not get dropped while dialing the number. Contact current rating — small relays switch a few amperes, large contactors are rated for up to 3000 amperes, alternating or direct current
Every time an electrical power device (for example: heaters, lamps, motors, transformers or similar power loads) turns on or off, its switch, relay or contactor transitions either from a CLOSED to an OPEN state ("BREAK") or from an OPEN to a CLOSED state ("MAKE"), under load, an electrical arc occurs between the two contact points (electrodes) of the switch.
The position of the contact breaker is set so that it opens (and hence generates a spark) at exactly the optimum moment to ignite the fuel/air mixture. This point is generally just before the piston reaches the top of its compression stroke. The contact breaker is often mounted on a plate that is able to rotate relative to the camshaft ...
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The majority of the wire spring relays manufactured in the 1960s had twelve fixed contacts. A normally open (make) contact, a normally closed (break) contact, or both can be provided for each fixed contact. A moving contact consists of two wires projecting out of the base of the relay, bent slightly inwards in order to exert pressure against ...