Help needed with Interposing relay information

[GAZ4333]

Hi,

Please could someone explain the basic operation of an interposing relay, as this is not something i have come across before? any help or information would be very welcome.

Regards

Gary

 

[Marmite]

A typical application is to achieve isolation between two separately derived dc tripping supplies.
For example to avoid exporting the dc out of the source substation curtilage and risking an incipient fault on the pilot cable discharging the substation battery. Another application may be to separate the utility tripping battery source from a customer's tripping source.
Regards
Marmite

 

[DRWeig]

Gary,

In controls, it's a term for any relay that sits between a control signal and another relay (or contactor) for purposes of isolation or contact rating.

Example: Output from a controller is dry contacts rated only 1A. Motor to be controlled needs a big contactor that will demand 3A of coil current plus inrush. In order to turn the motor on with the control output, you'll need an interposing relay with a coil current that the controller can handele and contacts that can handle the motor starter.

Make sense?

Good on ya,

Goober Dave