i've changed jobs and for the first time come across reyrole 11kv gear. theres a couple relays i don't know. interposing and intertripping. Any one any idea, reyrolle drawings are hard to follow.
Interposing Relay is the auxiliary relay which is used to isolate the two different systems (such as high current and low current or 24V control and 120V control or AC voltage and DC voltage etc.) in the control circuits. For example, if the motor's contactor coil voltage is 120V AC but PLC signal is 24V DC and it is required to operate the motor from the PLC signal, an interposing relay of 24V DC is used in the PLC circuit loop and its dry contact is wired in the 120V AC circuit to operate the motor. Its use is more common in between the instrument system (PLC or DCS) and the electrical system. However it is also used within the electrical system as well. It isolates the two different systems and so it is also called isolating relay. Some people think it couples two different systems and call it coupling relay.
Intertriping Relay is the relay which receives trip signal from one protection zone and trips a circuit-breaker at another protection zone.
- MS
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"All my technical advices in this forum must be consulted with and approved by a local registered professional engineer before implementation" - Mohammed Samad (Linkedin Profile: http://www.linkedin.com/in/msamad)
Reyrolle switches can be a bit confusing. Inter-tripping or interposing relays will be either B30 or B33 type (the ones that I know of, there may be more), with a variety of voltages, configurations, etc.
Inter-tripping is for panel mounted trips, I honestly don't know why they use these. They interface the various panel-mounted trips (not external trips) with the shunt trip.
Interposing relays interface external control with the shunt trip or closing circuits.
Reyrolle drawings aren't easy to follow, but they're no worse than any other switchgear manufacturers I've come across. You just have to get used to DC control. Control contacts on the OCB are also weird, early make, late make, early break and late break. They did my head in when I converted a switch to PLC control.
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Just a word of warning B30 & B33 relays are obsolete. They come in various voltages and reset functions so if you can find 2nd hand replacements take care. That being said I've only had one fail in 15 years on over 60 panels.
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Relays
Re: relays
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