page_254

< previous page | page_254 | next page >

Page 254

| Figure 13-14 Capacitor as a source of tripping energy. |

| Electronic Relays |

| Electronically activated relays are essentially data processing systems programmed for specific purposes. As such, they perform the same functions in the electric power field as their counterparts of electromagnetic and induction type relays. As indicated earlier, relays are intermediate devices that perform the function of a switch controlling the operation of some other device, but does not itself open or close the main circuit that is to be controlled. |

| Electronic relays have many advantages over the electromagnetic and induction relays. They require no physical break in connections, they have no moving or wearing parts, they have a quicker response in the overall switching function, and they require less energy to operate. Further, greater accuracy in settings is obtainable than with the coil taps and spring adjustments of electromagnetic and induction relays, resulting in greater flexibility and selectivity in line and equipment protection systems. |

< previous page | page_254 | next page >