Phoenix Contact Electromechanical Relays
Electromechanical relays transfer signals between its contacts through a mechanical movement. They are made of a coil, an armature mechanism and electrical contacts. When the coil is energized, the induced magnetic field moves the armature that opens and closes the contacts. Electromechanical relays are remote controlled switches capable of switching many circuits, either individually or in sequence. They have high reliability, low power consumption and a long switching operational life. Electromechanical relays are preferred for harsh environments. They are tolerant of high temperatures and perform well in areas prone to electromagnetic interference (EMI) and radio frequency interference (RFI). Surges, transients and noise do not affect an electromechanical protective relay.
Phoenix Contact PLC-INTERFACE relay series for universal use provides a wide range of plug-in electromechanical relays. The following special versions are available: Series for coupling sensors or actuators, filter series for long control cables, switch modules for manual intervention, relay modules for railway applications, relay modules for high inrush currents and reversing load relays for DC motors. The comprehensive product range optimizes installation with versatile accessories and provides easy connection technology (screw, spring-cage or Push-in).
Relays: Electromechanical vs Solid State
Electromechanical Relays
Electromechanical relays (EMR) use physical moving parts to achieve the desired functionality. These moving parts include the contacts that switch between the normally open and normally closed stationary contacts in the relay. This movement is made possible by an electromagnet. When power is applied to this magnet, it will act on the movable contact causing the relay to switch. In an EMR, it is common to hear the switching sound that is represented as a “clicking” noise. This audible noise can be helpful when determining the functionality of the relay.
Solid State Relays
Solid state relays (SSR) use a low power, electrical signal to generate an optical semiconductor signal that will transmit and energize an output signal. When this is activated, the input optical signal will act as the switch, allowing a higher voltage signal to pass through the relays output components. The internal circuitry of a SSR is far more complex than an EMR, but there are no physical moving parts.