Ssrs consist of electronic parts with no mechanical contacts. A simplified block diagram of an optically isolated ssr is shown to the left. Solid state relay or solid state switch electronicstutorials. With no moving parts, solid state relays avoid all the obvious mechanical failure modes associated with traditional relays. Introduction to solid state relays galco industrial electronics. A ssr solid state relay can perform many tasks that an emr. Singlephase3phase and number of elements for 3phase blank. Technical manual solidstate relays oem international ab. Solidstate relay circuit components electrical a2z. Necs ssr is named a ocmos fet optocoupled mos fet as the. Application, installation and maintenance of solidstate control. By alleviating electrical stress on the electronic components of the ssrs output circuit, failure and destruction due to surge voltage are suppressed.
Solid state relay circuit a solid state relay circuit consists of an input circuit, a control circuit, and an output loadswitching circuit. Solid state relays serve the same function as mechanical relays but have no moving parts. Static relay circuit using analog and digital ics for over current. As long as there is a necessity in circuit design to automate switch ing with electrical isolation, relays will continue to remain integral components. The led and photo array, for example, are molded in a translucent.
Sensors switches safety components relays control components automation systems motion drives. Compared to the electromechanical relay, the solid static relay has longer life. Moreover, this function is performed in an entirely static fashion. Introductiion the ssr that nec has started marketing uses a photocoupler system with a mos fet, explained in the following, as an output switch and a combination of an emitter and photo detector to drive the switch. Understanding solid state relays, ssrs electronics notes. The choice between traditional electromechanical relays and the solid state varieties often comes down to reliability and performance.
Dcac solid state relay switch for microcontrollerrobotic. An input circuit is the part of an ssr to which the control component is connected. Energy conservation support environment measure equipment. A solid state relay ssr is a re lay that does not have a moving contact. Load power supply voltage of 120 v load power supply voltage of 200 v load power supply voltage of 220 v load power supply voltage of 240 v load power supply voltage of 400 v load power supply voltage of 440 v load power supply voltage of 480 v. The mos fet in the ocmos fet corresponds to the contact in the mechanical relay, opening and closing the load circuit. A solid state relay circuit consists of an input circuit, a control circuit, and an output loadswitching circuit. The input circuit performs the same function as the coil of an emr.
Ssrs do not have the mechanical moving parts that mechanical relays. Photoctriac coupler zero cross circuit a circuit which starts operation with the ac load voltage at close to zerophase. Subsequently, in the early 1970s the solidstate relay ssr appeared on. Image adapted from solidstate relay handbook with applications by anthony bishop. Solid state relays can have a variety of different devices at the core of their electronic circuits. In terms of operation, ssrs are not very different fr om mechanical relays that have moving contacts. These relays transfer signals with electronic circuits. The pushon, toolfree quickconnect terminals make the z series ideal for highvolume oem applications. Trigger circuit a circuit for controlling the triac trigger signal, which turns the. Here is a simple circuit of one microcontrollercompatible dc signal controlled ac solid state relay switch, designed around an extremely compact g3mb202p 5vdc ssr from omron. Structure and operating principle ssrs use electronic circuits to transfer a signal. Throughout this manual we use notes to make you aware of safety considerations. The technology revolution in solid state switching relays.
Printed circuit series ssrs opto 22s printed circuit series allows oems to easily deploy solid state relays. The solid static relays was first introduced in 1960s. These circuits may be used in any combination to provide many different solidstate switching applications. Technical explanation for solidstate relays omron industrial. Solid state relay handbook galco industrial electronics. A solidstate relay is an electronic component which performs an interface function with electrical isolation between a control circuit, usually at low level, and a power circuit connected to loads which may have high power ratings motors, pumps, solenoid valves, heaters, etc. Ssrs, however, employ semiconductor switching elements, such as thyristors, triacs, diodes, and transistors. Ocmos fet, correspond to the coil in the mechanical relay. The solid state relay or solid state switch is a completely electronic device. They isolate the input from output and generate an output control signal on receipt of an input signal.260 682 352 1014 1533 1536 1363 1319 1129 657 678 86 941 885 649 188 731 489 384 762 687 183 724 903 827 245 1515 142 1174 1091 374 91 1378 1229 202