Safety Relays. Also called All–or–Nothing Relays with Positively Driven Contacts. Relays of this type have contacts that are mechanically connected together, such that if a normally open (NO) or make contact remains closed, a normally closed (NC) or break contact can not re–close. A safety relay detects wire breaks and faulty contactors/actuators by sending out electrical pulses through the wiring. By measuring the flow of current, the safety relay checks for welded contact sets and wire breaks.
Relays are the switches that aim at closing and opening the circuits electronically as well as electromechanically. It controls the opening and closing of the circuit contacts of an electronic circuit. A relay contains a coil, an armature, and at least one pair of contacts. Current flows through the coil, which functions as an electromagnet and generates a magnetic field. This pulls the armature, which is often shaped as a pivoting bracket that closes (or opens) the contacts. An electromechanical protective relay can typically manage a maximum of two performance parameters or protective functions.
The more complex varieties of the electromechanical relays (that may function based on the changes in electric electromagnetic forces) may be available as well. Relays can reduce the need for high-amperage wiring and switches, which are expensive and take up space. Therefore, switching to relays in your electronic systems can reduce the size or weight of a casing, for instance, or allow manufacturers to fit more functionality into a space of the same size.
